ACUS01 KWNS 051948
SWODY1
SPC AC 051946

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0146 PM CST Fri Mar 05 2021

Valid 052000Z - 061200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EAST
CENTRAL INTO SOUTHEAST TEXAS AND FAR SOUTHWEST LOUISIANA...

...SUMMARY...
A few thunderstorms capable of producing hail and gusty winds may
develop this afternoon over portions of east-central through
southeast Texas and far southwest Louisiana.

...Discussion...
No appreciable change was made to the previous convective outlook.

..Smith.. 03/05/2021

.PREV DISCUSSION... /ISSUED 1030 AM CST Fri Mar 05 2021/

...East central through southeast Texas...

As of late morning a cold front stretches from a surface low near
Gainesville, south southwestward through east central and south TX.
A warm front extends from the northwestern Gulf into southeast and
south central TX. Partially modified Gulf air with upper 50s to near
60 F dewpoints reside in the warm sector. Visible imagery still
indicates widespread low and mid-level clouds in pre-frontal zone,
but some of these clouds should mix out from the south and west
resulting in a narrow corridor of modest surface heating which
should boost MLCAPE to near 500 J/kg from east central into
southeast TX and possibly far southwest LA. Deeper forcing attending
a vorticity maximum embedded within a cutoff upper low circulation
will move from northwest TX into east central and southeast TX this
afternoon. This should foster thunderstorm development along and
east of the cold front later today. Though winds increase
substantially above 5 km, the anticipated relatively shallow
convective layer should limit effective bulk shear to between 30 and
40 kt. A few cells might develop weak mid-level updraft rotation and
when combined with 7 C/km mid-level lapse rates and modest
instability, could pose some risk for hail. Some clustering of
storms is possible and a few locally strong wind gusts might occur
before activity moves offshore this evening. Overall threat should
remain limited by the marginal thermodynamic environment.

$$
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ACUS01 KWNS 062000
SWODY1
SPC AC 061959

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0159 PM CST Sat Mar 06 2021

Valid 062000Z - 071200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE EAST
COAST OF SOUTH FLORIDA...

...SUMMARY...
A few strong to locally severe thunderstorms are possible through
the late afternoon near the east coast of south Florida.

...Discussion...
Other than the removal of low-severe probabilities near the Space
Coast in FL, the forecast remains largely unchanged and on track.
See the previous convective outlook for details.

..Smith.. 03/06/2021

.PREV DISCUSSION... /ISSUED 1030 AM CST Sat Mar 06 2021/

...Central/southern Florida Peninsula...
Thunderstorms have developed and increased across the north-central
Florida Peninsula. In spite of weak mid-level lapse rates,
relatively long hodographs accentuated by strong mid-level
westerlies atop east-northeasterly boundary layer winds, coincident
with modest but sufficient buoyancy, could support a few additional
strong to locally severe storms this afternoon across the
east-central Florida Peninsula.

Farther south in a somewhat more moisture-rich air mass, additional thunderstorm development is expected later this afternoon,
particularly across the near-coastal southeast Peninsula. This will
be coincident with relatively long hodographs (35-45 kt effective
shear) and upwards of 500-800 J/kg MLCAPE, which will be potentially
supportive of a few strong to locally severe storms.

$$
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ACUS01 KWNS 141952
SWODY1
SPC AC 141951

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Sun Mar 14 2021

Valid 142000Z - 151200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THROUGH THIS
EVENING FROM NORTHEAST CO INTO NORTHWEST KS AND SOUTHWEST NE...AND
LATER TONIGHT ACROSS PARTS OF THE LOWER MS VALLEY...

...SUMMARY...
Isolated severe thunderstorms are possible across a part of
northeast Colorado, northwest Kansas and southwest Nebraska through
early evening, and across a portion of the Lower Mississippi Valley
tonight.

...20z Update - CO/KS/NE...

The Marginal risk area has been shifted west/southwest this
afternoon. This is based on current surface observations and visible
satellite imagery. A surface low is located north of LAA and
southwest of ITR with an occluded front extending from the low
north/northeast a near the KS/NE border. Strong surface heating in
the vicinity of this boundary has resulted in weak destabilization
this afternoon and isolated thunderstorms have developed along the
boundary and near the surface low. Marginal hail will be possible
with this activity given steep midlevel lapse rates and moderate
shear. Low level shear will remain enhanced near the boundary, and a
funnel cloud has already been reported with a cell in Hitchcock
County NE. Brief funnels or even a weak tornado will remain possible
the next few hours. For more details, reference MCD 177.

Otherwise, the remainder of the outlook remains on track and no
other changes were made except to adjust 10% general thunder in line
with current observations.

..Leitman.. 03/14/2021

.PREV DISCUSSION... /ISSUED 1122 AM CDT Sun Mar 14 2021/

...Lower MS Valley...
A deep, occluded low over eastern CO will slowly fill as it drifts
east into western KS through tonight. An embedded mid-upper jet
streak will rotate around the southeastern periphery of the low,
in conjunction with a Pacific cold front moving from eastern OK/TX
into AR/LA by this evening. Only meager convection has been noted
this morning in the band of ascent along and behind the front. This
may continue through much of the period as a result of paltry
warm-sector buoyancy, as well as a capping inversion around 700 mb
in 12Z soundings from CRP-SHV-LZK. Still, conditional potential for
a tornado or isolated strong wind gust exists tonight as mid 60s
surface dew points spread toward the Ark-La-Miss and mid-level temps
slightly cool. This may result in a small corridor of spatiotemporal
overlap with 250-500 J/kg MLCAPE and a moderately enlarged low-level
hodograph.

...Northwest/north-central KS to southwest NE...
A narrow corridor of low-topped surface-based convection might
develop during the late afternoon to early evening along a
convergent occluded front where a plume of 40s surface dew points
can be maintained. Here, surface heating beneath rather cold
mid-level temperatures should result in steep low to mid-level lapse
rates. Low probabilities are maintained for marginally severe hail
along with a brief tornado from a cell or two.

$$
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ACUS01 KWNS 151950
SWODY1
SPC AC 151949

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0249 PM CDT Mon Mar 15 2021

Valid 152000Z - 161200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MO VALLEY AND MS/AL...

...SUMMARY...
Isolated severe storms are possible across parts of Alabama and
Mississippi through tonight. Isolated severe storms are also
possible from east-central Kansas through central Missouri through
early evening.

...20z Update...

The ongoing outlook remains on track and no changes are needed with
this update. Reference MCD 180 for short-term severe threat across
MS/AL, and MCD 181 for the short-term severe threat across KS/MO.

..Leitman.. 03/15/2021

.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Mar 15 2021/

...MS/AL...
A low-confidence severe threat remains apparent across the region
through tonight. A band of predominantly low-topped showers is
ongoing from northwest AL to southwest MS along a weakening surface
cold front, to the south of an embedded shortwave impulse advancing
north across the Mid-MS Valley. While further frontolysis is
expected, some of this convective activity should persist through
the afternoon and become more west/east-oriented across
northern/central AL and central MS. Broken cloudiness out ahead of
this activity will support further boundary-layer heating amid mid
60s dew points from the western half of AL to the southwest.
Low-level wind profiles should slowly weaken and become more veered
with western extent. The conditional threat for a supercell or two
during the late afternoon to early evening may be focused across the west-central AL vicinity where all hazards would be possible. Still,
given the poor forcing for large-scale ascent, probabilities remain
too low to warrant an upgrade this outlook. Otherwise, additional
convection may form overnight within a weak low-level warm advection
regime to the north of the central Gulf Coast. Rich low-level
moisture and continued strong deep-layer shear may support a
low-probability severe threat.

...East-central KS to central MO...
The deep closed low over central KS will evolve into an open wave
and eject east-northeast across the Midwest through tonight, in
response to upstream height falls with a strong shortwave trough
digging across CA. Though the richer low-level moisture is confined
to the Lower MS Valley, lingering boundary-layer dewpoints in the
mid to upper 40s are prevalent within the northern extent of robust
insolation across southeast KS and southwest MO. Beneath cold
mid-level temperatures, the steep-lapse-rate environment will
support meager MLCAPE approaching 500 J/kg in a corridor east of the
surface cyclone and along a stalled front in central MO.

Within the left-exit region of a strengthening mid-level jet,
isolated to scattered thunderstorms are expected to form by mid
afternoon in the zone of ascent near/east of the surface low towards
the KS/MO border, with successive development of storms eastward
into central MO through early evening. Wind profiles, especially
with eastern extent in central MO, should support a couple
low-topped supercells with effective bulk shear of at least 30 kt
and some hodograph curvature in the low levels. Marginally severe
hail, isolated damaging gusts, and a tornado will be possible with
storms along the boundary this afternoon/evening. The bulk of
convection should generally propagate further across the cool side
of the front, where low-level stratus will likely remain pervasive,
and become elevated before weakening later this evening.

$$
--- SBBSecho 3.12-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)

ACUS01 KWNS 182127
SWODY1
SPC AC 182126

Day 1 Convective Outlook AMEND 1
NWS Storm Prediction Center Norman OK
0426 PM CDT Thu Mar 18 2021

Valid 182000Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN
SOUTH CAROLINA THROUGH CENTRAL AND EASTERN NORTH CAROLINA AND
SOUTHEAST VIRGINIA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE SOUTHERN APPALACHIANS AND A PORTION OF NORTHERN FLORIDA...

AMENDED FOR TO EXPAND ENHANCED RISK FARTHER NORTH INTO SOUTHEAST
VIRGINIA FOR TORNADO AND DAMAGING WIND THREAT

...SUMMARY...
Scattered severe storms remain possible this afternoon and evening
mainly from a portion of South Carolina through central and eastern
North Carolina and southeast Virginia. Other strong to severe storms
are possible this afternoon over the southern Appalachian region as
well as northern Florida.

...South Carolina through central and eastern North Carolina and
southeast Virginia...

Cluster of storms over western SC and southwestern NC is expected to
continue developing northeast through central and eventually eastern
NC this afternoon and evening. Vertical wind profiles with 50+ kt
effective bulk shear and sizeable 0-2 km hodographs will remain
supportive of organized severe storms including supercells. However,
trend has been for a pocket of dry air in the low levels to advect
northward through northern SC into southeastern NC, and this has at
least temporarily reduced boundary layer instability. Nevertheless,
some low-level theta-e advection will resume in wake of the dry
pocket contributing to 1000-1500 J/kg MLCAPE. The best chance for
severe storms are expected as activity develops northeast along
instability gradient through a portion of central and eastern NC and
possibly southeast VA this afternoon and evening with damaging wind,
large hail and a few tornadoes possible.

...Southern Appalachian region...

Storms are developing within corridor of ascent just east of the
progressive shortwave trough. Cold temperatures aloft, steep lapse
rates and diabatic heating will continue to foster widely scattered
storm development this afternoon. Isolated large hail and a few
locally strong wind gusts are the main threats. Activity should
diminish toward late afternoon or early evening.

..Dial.. 03/18/2021

.PREV DISCUSSION... /ISSUED 1133 AM CDT Thu Mar 18 2021/

...Southeast...
Overall severe threat will likely focus in two corridors which are
encompassed by the cat 3/ENH risk for tornado and wind. Initial
broken band of non-severe convection is ongoing from south-central
GA through the eastern FL Panhandle. This activity has struggled to
intensify despite strong low to deep-layer shear as it impinges on a
relative minimum in buoyancy sampled by the 12Z JAX sounding and
evident in mesoanalysis time-series. However, destabilization is
occurring downstream from north FL to the coastal Carolinas and
redevelopment of severe storms is anticipated at some point this
afternoon. The eastward translation of a 50-55 kt LLJ will support
an enlarged hodograph favorable for a few supercells. Modest
mid-level lapse rates will remain a limiting factor, though MLCAPE
will be large enough given to support a few tornadoes and scattered
damaging winds, with a strong tornado or two still possible.

The separate area of potential severe should be coincident with the
track of a mesolow from the northeast GA/northwest SC border across
the Piedmont towards south-central VA. Here, MLCAPE will likely
remain weak but cloud breaks just ahead of the low near the
mid-level dry slot may prove sufficient for an intensifying area of
convection. Where sufficient buoyancy overlaps the more
favorable/curved hodographs east of the mountains, a couple
supercells capable of a strong tornado, damaging winds, and isolated
large hail will all be possible this afternoon/evening.

...OH Valley...
East and southeast of the weakening occluded cyclone, pockets of
stronger boundary-layer heating are underway on the nose of the
mid-level dry slot. In conjunction with cool mid-level temperatures,
500-1000 J/kg of MLCAPE will be sufficient for a few strong-severe
storms later this afternoon. This area will be on the northwest edge
of the stronger flow/shear, where a mix of multicell clusters and a
few low-end supercells are probable. A tornado or two, large hail,
and damaging winds will be possible.

$$
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ACUS01 KWNS 251246
SWODY1
SPC AC 251245

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Thu Mar 25 2021

Valid 251300Z - 261200Z

...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS WITH A TORNADO
OUTBREAK EXPECTED ACROSS PARTS OF NORTHERN MISSISSIPPI...NORTHERN
ALABAMA...AND SOUTHERN TENNESSEE...

...SUMMARY...
A tornado outbreak -- including the threat of a few long-tracked,
violent tornadoes -- is expected today into early this evening over
the Southeast, especially parts of Mississippi, Alabama and
Tennessee. Tornadoes, large to very large hail, and damaging winds
to hurricane force also are possible over a broad area from the
central Gulf Coast to the Ohio Valley and southern Appalachians.

--- Technical Discussion ---

...Synopsis...
In mid/upper levels, a longwave trough will be maintained over the
western CONUS, as a strong shortwave trough and related speed max
dig south-southeastward across the interior Northwest, and a
formerly basal trough ejects northeastward. The latter trough is
evident in moisture-channel imagery over the southern High Plains to
the Big Bend region of TX, and will move to MO/AR by 00Z. By 12Z,
this feature should reach Lake Erie and OH. This trough will pack
the height gradient to its southeast enough to yield 110-130-kt
250-mb flow and 80-100-kt 500-mb winds over much of the Mid-South,
and Tennessee/Ohio Valleys today and this evening.

The associated surface low-pressure area was analyzed at 11Z across
western AR to northwestern LA, still poorly consolidated around
areas of rain-cooled air. A cold front was drawn from northwestern
LA across southeast TX the middle TX Coast and deep south TX. A
"synoptic" warm front arched from the low-pressure

ACUS01 KWNS 270553
SWODY1
SPC AC 270551

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1251 AM CDT Sat Mar 27 2021

Valid 271200Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
ARKANSAS TO MIDDLE TENNESSEE...

...SUMMARY...
Severe storms are expected across the lower Mississippi through
Tennessee Valley regions. All hazards are possible including very
large hail, damaging wind, and tornadoes. Potential for a strong
tornado exists from eastern Arkansas into western Tennessee. Other
severe storms are possible across a portion of the Midwest with
isolated damaging wind and large hail the main threats.

...Lower MS Valley/TN Valley...

Large-scale heights will not change appreciably until late in the
day1 period across the lower MS and TN Valley region. Water-vapor
imagery depicts an upper low digging southeast across AZ early this
morning. This feature is forecast to translate across far West TX
during the evening before deamplifying as it ejects into
north-central TX late. Prior to the influence of this feature, one
LLJ branch will extend across the TX Coast-LA-middle TN. Low-level
warm advection in association with this feature is expected to
encourage a considerable amount of convection that should be ongoing
at the start of the period. Several members of the HREF suggest a
possible MCS may evolve over middle TN, then propagate east during
the day. Areal extent of this activity may greatly influence
convective development later in the day as rain-cooled boundary
layer may establish an outflow boundary that could drape west across
TN.

Strongest low-level heating will be noted south of this rain-cooled
air mass, and buoyancy should be greatest from northeast TX into
northern MS where SBCAPE will exceed 2000-2500 J/kg. With
temperatures warming into the mid-upper 70s, it appears surface
parcels will reach their convective temperatures by 20z and
scattered discrete storms will likely develop from the Arklatex,
northeast toward the early-day outflow boundary over western TN.
This corridor will likely experience significant convective coverage
by the end of the period.

Forecast wind profiles favor supercells and lapse rates should be
sufficiently steep for very large hail with storms across the
western half of the ENH Risk. Tornadoes are also possible, a few
potentially strong, with discrete storms, though QLCS-type spin ups
are also possible as a squall line matures later in the evening. As
the squall line matures, the threat for strong, damaging winds will
become more likely as deep-layer westerly flow increases across the
mid-South Region.

Farther north, strong mid-level height falls will overspread the
upper Midwest region in advance of a northern branch short-wave
trough that will dig into WI/IA/MO by 28/12z. It's not entirely
clear how much moisture/instability will be drawn north ahead of the
surface low into eastern MO/IL prior to convective initiation. 00z
NAM suggests mid 50s surface dew points will advance across this
region which will help destabilization; however, nearest mid 50s
surface dew points are roughly 300 mi south across southeast
AR/northern MS. If early-day convection disrupts this moisture flow,
then somewhat less buoyancy may be available for convection
extending ahead of the low into central IL. At this time wind/hail
appear to be the primary risks with robust storms along the front.

..Darrow/Dean.. 03/27/2021

$$
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ACUS01 KWNS 271957
SWODY1
SPC AC 271955

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Sat Mar 27 2021

Valid 272000Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
INTO TONIGHT FROM PARTS OF THE ARK-LA-TEX ACROSS THE MID SOUTH AND
TN VALLEY...

...SUMMARY...
Severe storms are likely this afternoon into tonight from the
Ark-La-Tex east-northeastward across parts of the Mid South and
Tennessee Valley. All hazards are possible including very large
hail, significant damaging winds, and a couple of strong tornadoes.

Only minor changes have been made to adjust for the ongoing cluster
of storms moving east across North Carolina. Elsewhere, the forecast
remains on track. See the previous discussion for more details.

..Wendt.. 03/27/2021

.PREV DISCUSSION... /ISSUED 1124 AM CDT Sat Mar 27 2021/

...Mid South/TN Valley region through tonight...
Elevated convection with a marginal hail threat that formed
overnight in a zone of warm advection, along and north of the
surface warm front from the Mid South into middle/eastern TN,
persists as of late morning. The convection is also associated with
a subtle mid-upper speed max moving east-northeastward over the Mid
South. Farther west, additional storm development is expected by
early-mid afternoon along the rain-reinforced front close to the
MS/AL/TN border region. This afternoon convection will likely be
rooted at the surface as the low levels continue to warm/moisten
from the south, with a few supercells possible with MLCAPE near 2000
J/kg, effective bulk shear near 50 kt, and effective SRH around 150
m2/s2.

Farther west into northeast TX and southern/eastern AR,
surface-based supercell development is expected by mid afternoon
along the moisture gradient/warm front, as the low levels continue
to destabilize and the cap weakens. The forcing for ascent will be
rather subtle, so the primary storm mode should be a mix of discrete
supercells and clusters moving east-northeastward along the buoyancy gradient/front this afternoon into early tonight. Isolated very
large hail, damaging winds, and a couple of tornadoes will be the
main concerns this afternoon. Some increase in low-level shear is
expected this evening, which will support an increase in the tornado
threat, with an isolated strong tornado or two possible. Otherwise,
storms overnight should consolidate into more of a solid band as the
synoptic cold front overtakes the convection from the northwest, in
response to phasing of the northern and southern streams, with
cyclogenesis from IL to Lower MI.

...Eastern OK/northwestern AR to IL this afternoon/evening...
The primary surface cyclone is expected to begin deepening this
evening across IL, before moving to Lower MI overnight. In the wake
of the low, a cold front will begin to accelerate southeastward
later this evening into tonight. The primary uncertainties along
this corridor are the degree of low-level
moistening/destabilization, and the magnitude of the low-level
shear. The main low-level mass response/low-level jet will likely
be directed into the rather persistent zone of convection farther to
the southeast along the effective warm front from northeast TX to
western TN. These factors suggest substantial limitations to the
wind/hail threat along the cold front farther to the northwest, with
the most questionable area centered on northwestern AR.

...Carolinas this afternoon/evening...
The cluster of storms in eastern TN has been elevated through the
morning, but some northward expansion of the surface warm sector is
expected through this afternoon from SC into NC. Given sufficient
deep-layer vertical shear, an organized cluster with some threat for
damaging winds/large hail may persist into the afternoon along the
warm front from the Piedmont eastward across NC and adjacent
portions of SC.

$$
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ACUS01 KWNS 280556
SWODY1
SPC AC 280555

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Sun Mar 28 2021

Valid 281200Z - 291200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
SOUTHEASTERN VIRGINIA AND ADJACENT FAR NORTHEAST NORTH CAROLINA...

...SUMMARY...
Scattered severe storms are likely along an advancing cold front
from the Mid-Atlantic into the Carolinas. The highest confidence in
damaging winds is in southeastern Virginia and vicinity. Farther
south and west, a few strong to severe storms are possible from
Mississippi into Georgia.

...Synopsis...
Shortwave trough currently extending from the Upper Midwest back
southwestward through the central Plains will continue eastward
throughout the day, moving through the Great Lakes, OH Valley,
Mid-Atlantic and much of the Northeast. As it does, the system is
expected to mature significantly, with both a deep surface low over
southern Quebec and strong mid-level flow from the TN Valley into
the Mid-Atlantic predicated by this afternoon.

A cold front will also accompany this system. Expectation is for
this front to extend from western NY southwestward along the central
and southern Appalachians by around 18Z this afternoon. The front is
forecast to be off the Northeast and Mid-Atlantic coasts by 00Z
Monday. A broad area of at severe potential will exist of this front
from the northern Mid-Atlantic into the Southeast.

...Mid-Atlantic/Carolinas...
Ongoing convective system over the TN and Lower MS Valleys is
expected to continue eastward/northeastward this morning and into
this afternoon. Most of the 00Z guidance is too slow with the
forward progression of the system, particularly the portion entering
middle TN, where more forward propagation has been noted. While some
slowing of convective line is likely has instability wanes with
eastern extent, overall expectation is for this area of convection
to reach central VA/NC this morning.

As such, severe potential across the region will be tied to the
potential for re-development along the front. The bulk of the
guidance suggests destabilization will occur ahead of the front, and
that a strongly forced line will develop along the front. Intense
low to mid-level flow will favorable strong, convectively enhanced
wind gusts within this line. A few embedded tornadoes are possible
as well.

Given this severe potential, 30% wind/5% probabilities will be
maintained with this outlook. However, uncertainty regarding the
stability of the air mass preceding the front merits close
observation of overnight trends and guidance, with potential
downgrades needed in subsequent outlooks.

...Southeast...
Modest buoyancy will continue to promote thunderstorm development
along the front as it moves across the region this morning and into
this afternoon. Low-level winds will likely veer before frontal
passage and stronger flow aloft will be increasingly displaced
north. However, the environment will remain conducive to
occasionally organized storms capable of strong downbursts. A brief
tornado or two could also occur within the line, particularly over
northern GA where low-level flow is expected to remain strong as the
line moves through.

..Mosier/Karstens.. 03/28/2021

$$
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ACUS01 KWNS 301559
SWODY1
SPC AC 301557

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1057 AM CDT Tue Mar 30 2021

Valid 301630Z - 311200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND TONIGHT FROM THE ARKLATEX REGION INTO THE TENNESSEE VALLEY....

...SUMMARY...
Thunderstorms are expected to develop across the ArkLaTex region and
lower Mississippi through Tennessee Valleys, mainly late this
afternoon and tonight, with isolated strong/severe thunderstorms
possible.

...Arklatex into the Tennessee Valley...
Morning water vapor loop shows a broad upper trough across the
northern Plains and Rockies, with moderately strong
west-southwesterly flow aloft extending from TX into the southeast
states. A cold front is pushing southeastward across OK/MO and will
move into the Arklatex and TN Valleys tonight. Southerly low-level
winds ahead of the front will help to moisten/destabilize the
region, with dewpoints in the 60s and MUCAPE values of 500-1000 J/kg
this evening and tonight. This will lead to a rather broad area of
scattered thunderstorm potential. 12z CAM solutions generally agree
in isolated coverage of storms, and suggest that weak large-scale
forcing will limit the overall updraft/downdraft intensities.
However, forecast soundings show profiles generally favorable for
the risk of hail and gusty winds in the stronger cells that can
develop. Therefore, will maintain the broad MRGL risk category at
this time.

..Hart/Lyons.. 03/30/2021

$$
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ACUS01 KWNS 111259
SWODY1
SPC AC 111258

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 AM CDT Sun Apr 11 2021

Valid 111300Z - 121200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TODAY OVER
CENTRAL FLORIDA...

...SUMMARY...
The main severe-thunderstorm threat today will be over portions of
the Florida Peninsula, with damaging wind and occasional hail
possible. A tornado cannot be ruled out as well.

...Synopsis...
The mid/upper level pattern will continue to feature split flow
across central North America, but with some shift in the location
and amplitude of the splitting. That mainly will be related to two
features:
1. A cyclone now centered near the IL/IN state line, and forecast
to gradually shrink/fill as its circulation center crosses IN and
northern OH through the period.
2. An initially open-wave, neutral-tilt trough over SK, eastern MT
and northern WY, which will evolve into a closed cyclone as it
crosses the northern Great Plains today. By 12Z tomorrow, the
500-mb low should be near the SD/ND/MN border confluence, along a
trough oriented west-northwest to east-southeast.

In the southern peripheral cyclonic flow of the leading upper low,
two small but important shortwave troughs are apparent: the first a convectively enhanced vorticity lobe over the northeastern Gulf
south of the FL Panhandle, and the second upstream across southeast
TX and LA. These perturbations will proceed eastward across
central/northern FL and the central northeast Gulf Coast regions
through 00Z, with the trailing one crossing northern/central FL
tonight.

At the surface, 11Z analysis showed a primary occluded low over
northern IL, with another near a triple point over northern Lower
MI. A cold front extended from there across eastern OH, to the TRI
and MOB areas, and across the northwestern Gulf. The surface low
(or lows, in a broad cyclone with more than one center possible)
should meander around the states bordering Lake Michigan through the
period. Another cold front associated with the northern Plains
upper trough should move southeastward over the northern/central
Plains and southern High Plains. The cold front related to the
Great Lakes cyclone will shift southeastward over the Carolinas, GA
and northern FL, where convective processes will be largely
prefrontal.

...FL...
Scattered to numerous thunderstorms are expected to evolve from the
ongoing, initially loosely organized activity over the northeastern
Gulf. The resulting convection should sweep across and down the
peninsula today in an increasingly organized, largely forward-
propagational MCS. The main threat will be damaging gusts, some
severe, and a tornado or two cannot be ruled out. (See SPC severe
thunderstorm watch 91 and related mesoscale discussions for
near-term situational coverage.) The main threat area, with
greatest concentration of severe-wind potential, currently appears
to be portions of central and perhaps south-central FL that
experience longer-duration diurnal heating and sustained moisture advection/transport ahead of the complex.

Veering flow with time is expected in much of the pre-MCS boundary
layer, and should have these influences:
1. Making deep-layer winds more unidirectional, with the mean-wind
and deep-shear vectors assuming substantial component along the
convective axis, thereby supporting denser, quasi-linear
configuration,
2. Reducing low-level shear and hodograph size somewhat (but not
enough to forbid QLCS tornado potential entirely) and
3. Advecting higher-theta-e Gulf air across the central/southern
peninsula, supporting potential MLCAPE of 1500-2000 J/kg.

The complex should reach South FL this evening at the latest, and
may affect portions of the Keys as well. Mesoscale trends as the
MCS and its cold-pool/pressure perturbation evolves likely will
compel further extension or adjustment of the probabilities today.

...Mid-Atlantic region...
Widely scattered thunderstorms may develop this afternoon, mainly
along and east of a surface prefrontal/lee trough, moving eastward
to northeastward over the outlook area. Isolated damaging gusts
and/or marginally severe hail are possible.

For generating buoyancy, diurnal destabilization of the boundary
layer behind the morning clouds/precip will help to offset some
relatively weak midlevel lapse rates, along with surface dew points
commonly in the 50s to low 60s north, low/mid 60s south. Depending
on the duration of heating, some mixing-related reduction in surface
moisture is possible, tempering CAPE somewhat, but at the same time,
yielding more evaporation-favoring subcloud layers for localized
acceleration of downdrafts. Peak MLCAPE in the 500-1000 J/kg range
is possible -- locally higher in the southern parts. The main
factor precluding a better-organized threat will be lack of
substantial vertical shear, with only 25-35-kt effective-shear
magnitudes expected (also locally/briefly greater).

..Edwards/Broyles.. 04/11/2021

$$
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ACUS01 KWNS 171232
SWODY1
SPC AC 171231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Sat Apr 17 2021

Valid 171300Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE
GULF COAST STATES...

...SUMMARY...
Isolated severe hail is possible over Deep South Texas this morning.
Isolated severe hail and damaging winds are possible across portions
of the central Gulf Coast through north Florida, mainly during the
late afternoon and evening.

...Central Gulf Coast to north FL...
A quasi-stationary front remains ensconced across far southern LA to north-central FL. A leading swath of convection driven by low-level
warm advection is ongoing along and north of the FL portion of the
front and this should push east off the South Atlantic Coast by
midday. The next round of elevated convection should develop across
the northern Gulf later this morning and spread east-northeast
across the northeast Gulf Coast region this afternoon into this
evening. Mid-level lapse rates will remain weak, yielding primarily
thin elevated buoyancy, but mid-level flow will remain strong,
contributing to favorable vertical shear for the threat of isolated
severe storms. Primary threat will be marginal hail, although a
damaging wind gust or two may be able to penetrate the relatively
shallow low-level stability. Some northward retreat of the surface
front may support convection containing surface-based effective
inflow parcels across north FL this evening.

...Deep South TX...
A few post-frontal elevated thunderstorms are ongoing across the
Lower Rio Grande Valley and should spread into the northwest Gulf
later this morning. Individual cells have repeatedly weakened over
the past few hours despite 500-1200 J/kg of thin effective-layer
CAPE amid 60-70 kt effective shear per the 12Z Brownsville and
Corpus Christi soundings. Nevertheless, the environment suggests a
discrete supercell producing severe hail is still possible through
midday.

..Grams/Broyles.. 04/17/2021

$$
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ACUS01 KWNS 180516
SWODY1
SPC AC 180514

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1214 AM CDT Sun Apr 18 2021

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR CENTRAL
FLORIDA...

...SUMMARY...
Isolated strong to severe storms may occur today across parts of the northern/central Florida Peninsula, with gusty winds and hail the
main threats.

...Synopsis...
Mostly zonal flow with periodic low-amplitude shortwave troughs will
persist from the Gulf Coast states to Florida through the period. At
the surface, a stalled front will be present from the central Gulf
of Mexico to the central Florida Peninsula. This front will be a
focus for storm activity through the day Sunday with the potential
for a few strong to severe storms.

...Florida...
A mid-level shortwave trough located off the Florida Peninsula early
Sunday morning will shift eastward by morning and may provide enough
ascent for scattered storm activity across north-central Florida.
However, regional radar shows the surface front moving south from
Citrus to Flagler counties with areas north of this boundary more
stable. This may reduce the intensity of any convection which forms
across north-central Florida early in the day.

The aforementioned front is expected to stall somewhere near Orlando
with little movement expected through the day. Temperatures are
forecast to increase into the 80s with dewpoints ranging from the
upper 60s to low 70s by the afternoon. Nebulous forcing may keep
storm coverage isolated from late morning through mid-afternoon.
However, by the late afternoon/evening, weak mid-level height falls
are expected to overspread the region and this subtle ascent
combined with an unstable boundary layer should be sufficient for
scattered storm development. Effective shear in excess of 40 knots
should aid in storm organization and may support some supercell
structures. Mid-level lapse rates around 7 C/km are not overly
steep, but should be sufficient for a threat for isolated large
hail, especially if any sustained rotating updrafts can develop.
Overall, scattered strong storms with isolated severe storms are
expected with a threat for both large hail and damaging winds.

An isolated strong to severe storm threat may persist overnight as
the low-level jet strengthens and low-level moisture advection
sustains surface based instability ahead of the surface front as it
slowly moves south along the Peninsula.

Elsewhere, some gusty winds may accompany storm activity in the
northern Rockies as storms form in an environment with a dry
sub-cloud layer and moderately strong northwesterly flow 0.5 to 1 km
AGL. Limited instability precludes the addition of a marginal risk
at this time.

..Bentley/Jewell.. 04/18/2021

$$
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ACUS01 KWNS 221240
SWODY1
SPC AC 221238

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0738 AM CDT Sat May 22 2021

Valid 221300Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/SOUTHERN
HIGH PLAINS...

...SUMMARY...
Scattered severe hail and wind along with a few tornadoes are
possible across the central and southern High Plains this afternoon
through about dusk.

...Central and southern High Plains...
Within a meridional mid to upper-level flow regime downstream of an
amplified trough over the West, the western extent of mid 50s to low
60s surface dew points have reached the High Plains of eastern
CO/NM. While some eastward mixing will occur, multiple rounds of
scattered thunderstorms are expected to begin during the early
afternoon. Low-level hodographs initially may remain modest, but
should enlarge with time by late afternoon. A mixed mode of
supercells evolving into broader clusters is anticipated,
particularly in two regimes focused on eastern NM and separately in
northeast CO to western NE. Moderate buoyancy should develop within
confined corridors just ahead of this convection which should
support potential for a few tornadoes, in addition to severe hail
and wind.

...Central TX...
An MCV located just east of San Antonio should gradually advance
northwest across central TX through this afternoon. Low-topped
showers and isolated thunderstorms are expected to peak in coverage
from late morning through afternoon. A belt of enhanced 0-1 km shear
within the eastern quadrant of the MCV coupled with limited
boundary-layer heating may be sufficient for the threat of
brief/weak tornadoes.

...Northern MN...
Isolated thunderstorms may develop during the late afternoon to
early evening along the trailing portion of a modest warm conveyor
belt along/just ahead of a slow-moving cold front. The presence of
an upstream mid-level ridge over the Dakotas within a pronounced
gradient of mid-level westerlies suggest the corridor of severe
potential should remain spatially confined. Isolated severe hail and
locally damaging winds are possible.

..Grams/Mosier.. 05/22/2021

$$
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ACUS01 KWNS 231208
SWODY1
SPC AC 231207

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0707 AM CDT Sun May 23 2021

Valid 231300Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS WESTERN
SD/NE...

...SUMMARY...
Scattered to numerous severe thunderstorms are expected across a
large portion of the western Great Plains. The most likely corridor
for a few tornadoes and significant severe wind/hail is from western
South Dakota to the central High Plains.

...Western/central SD to the CO/KS border...
A surface cyclone in the lee of the Front Range will deepen as it
tracks north-northeast into western SD by this evening. Northward
advancement of the low in tandem with the surface warm front will
result in poleward advection of upper 50s to lower 60s surface dew
points towards the SD/ND border. Moderately steep mid-level lapse
rates of 7-7.5 C/km should support an increasingly expansive plume
of moderate buoyancy with MLCAPE of 1000-2000 J/kg by peak heating.

Pronounced mid-level height falls will overspread the region as a
vort max embedded within the basal portion of the broader trough
over AZ ejects northeast. Accompanied by an intense speed max,
thunderstorms will rapidly develop by early to mid-afternoon within
a strengthening deep-layer shear regime. Supercells will be favored
initially but a quick transition into a northeast-moving QLCS is
expected near the WY/SD/NE/CO border areas given the meridional flow
regime. Large hail will be likely mainly early, with severe wind
gusts becoming the primary hazard as upscale growth occurs across
western portions of SD/NE.

The potential for a few tornadoes is apparent across three primary
corridors within the ENH and SLGT risk regions. First, any storm in
proximity to the surface cyclone and warm front, where locally
enhanced 0-1 km SRH (at or above 200 m2/s2) will exist. Second,
embedded QLCS circulations are also possible as the line matures
during the late afternoon to early evening. Finally to the south of
the QLCS, a couple discrete supercells may persist through about
dusk near the CO/KS border amid plentiful low-level moisture/SRH.

...Southern High Plains...
Isolated to scattered thunderstorms are expected to develop during
the afternoon in the vicinity of the dryline from the Raton Mesa
vicinity to the Trans-Pecos of far west TX. A mix of supercells and
multicell structures will be most favored in the Raton Mesa vicinity
along the glancing periphery of the ejecting trough. Large hail,
severe wind gusts, and a tornado or two are possible.

...Northeast...
Convective coverage will likely remain sparse owing to modest
convergence along a predominately west/east-oriented cold front,
which will be pushing south across the region this afternoon.
Despite weak mid-level lapse rates, surface temperatures warming
into the 80s amid upper 50s to low 60s dew points should support
weak buoyancy with MLCAPE of 250-750 J/kg. Along the periphery of a
mid-level speed max ejecting across northern ME, adequate and nearly unidirectional deep-layer shear will exist for a few cells capable
of producing locally damaging winds.

..Grams/Mosier.. 05/23/2021

$$
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ACUS01 KWNS 191259
SWODY1
SPC AC 191257

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 AM CDT Sat Jun 19 2021

Valid 191300Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
CENTRAL PLAINS...LOWER MISSOURI/OHIO VALLEYS...MID-ATLANTIC...AND
CENTRAL GULF COAST...

...SUMMARY...
Damaging thunderstorm wind and isolated large hail are possible from
portions of the central High Plains to the Mid-Atlantic. A tornado
threat also exists over parts of the central Gulf Coast States to
southwestern Georgia, east of the inland track of Tropical Storm
Claudette.

...Synopsis...
In mid/upper levels, the main belt of northern-stream westerlies
will become more cyclonic through the period from the northern
Rockies to the Northeastern CONUS, as a series of shortwaves lead to
height falls. As this occurs, the strong and persistent anticyclone
to the south, over the Desert Southwest, will shift southward
slightly, with the 500-mb high approaching the southern border of AZ
by the end of the period. In between, a perturbation initially
apparent in moisture-channel imagery over UT will move eastward,
reaching southern WY and the CO Western Slope by 00Z. This trough
should move over parts of the central Plains overnight, potentially
with some convective vorticity reinforcement.

Farther east, a strong shortwave trough will move from its present
location over the western Lake Superior region and WI across the
rest of the upper Great Lakes, with some weakening expected by 00Z
as it reaches the Lake Erie vicinity. The trough should pivot
eastward from there to southern New England by 12Z tomorrow. A weak
mid/upper low will remain over east-central/southeast TX in the CLL
area, as the perturbation accompanying T.S. Claudette ejects
northeastward across MS/AL.

The 11Z surface analysis showed a cold front across portions of
southeastern ON and Lake Ontario, which should move eastward/
southeastward into parts of NY and New England today into tonight.
The wavy frontal zone extended through a low over southern WI,
southwestward across extreme southeastern NE to another low near the
southern part of the CO/KS line. Frontolysis is expected along the
High Plains portion of the boundary today, though easterly flow
components to its north and relatively maximized low-level moisture
will persist.

...Central Plains...
Widely scattered to scattered thunderstorms should develop this
afternoon over western parts of the outlook area, from the NE
Panhandle across parts of eastern CO. As this activity moves
roughly eastward through the late afternoon and early evening, it
will encounter greater moisture and intensify, offering the threat
for damaging gusts and large hail. The wind threat will
increase/maximize when upscale cold-pool aggregation and related
forced ascent can occur, while the foregoing boundary layer remains
deep and well-mixed, favoring downdraft acceleration. As such, the
potential for significant/65+ kt gusts is maintained over parts of
the High Plains.

As aforementioned height falls occur from this area northward, winds
aloft will become more difluent and strengthen slightly,
contributing to favorable deep shear. Meanwhile, large-scale ascent
and low-level mass response will increase with the approach of the
UT perturbation, leading to increased convergence north of the
remnant front, near a lee trough. Destabilization will occur aloft
with the DCVA and in the boundary layer from strong diurnal/diabatic
heating, leading to steep lapse rates, with peak MLCAPE in the
2000-2500 J/kg range. This will support the initial development and
upscale growth. Eastward extent of the nocturnal wind threat into
lower elevations and greater MLCINH (but also a strengthening
southerly LLJ) is uncertain, and largely dependent on depth/strength
of the MCS cold pool.

...Lower Missouri/Ohio Valleys...
Widely scattered to scattered thunderstorms in clusters are possible
this afternoon and evening, offering damaging gusts and severe hail.
Aggregated outflow from the prior day's and night's convection has
left a boundary across parts of northeastern KY and southern IN/IL,
to near STL, and west-northwestward across northern MO. Isolated
severe hail may be noted this morning with elevated convection north
of the boundary, though the supportive west-southwesterly to
westerly LLJ branch should weaken over the next few hours.

Despite weak shortwave ridging behind the upper Great Lakes trough,
strong low-level moisture/heating are likely along and south of the
boundary, which may drift back northward over parts of MO. A
boundary-parallel corridor of MLCAPE in the 3000-4000 J/kg range is
possible, amidst surface dew points from the upper 60s to low 70s F,
weak CINH, and a deep troposphere to aid in the development of
deeply buoyant profiles. Although forecast soundings suggest modest
deep shear, localized low-level shear/vorticity enhancement by the
boundary, and well-mixed subcloud layers on the warm side, may aid
storm organization as well. Low-level warm/moist advection may help
some of the convection to persist at severe levels tonight across
the Ohio Valley region. A relative minimum in severe potential may
exist between this regime and that over the central Plains; however,
confidence in that is not high enough yet to carve out lower
unconditional probabilities.

...Mid-Atlantic/Northeast...
Widely scattered to scattered thunderstorms are expected to form
through this afternoon over western parts of the outlook area,
especially over portions of western/central PA toward northern MD,
and move eastward with the threat for strong-severe gusts and large
hail. Some guidance indicates the potential for upscale clustering
over the lower DE Valley region and/or NJ before activity moves
offshore. Large-scale lift is expected to increase over the region
ahead of the upper Great Lakes shortwave trough, spreading ahead of
the cold front. Meanwhile, low-level destabilization will occur
diurnally, steepening deep-layer lapse rates with favorable moisture
in place. An area of 500-1500 J/kg MLCAPE should result, amidst
favorable deep shear. Although low-level flow will be weak and
veered, a 45-55-kt 500-mb speed max should shift over the region,
contributing to effective-shear magnitudes in the 35-45-kt range.
Organized multicells and isolated supercells are possible.

A separate area of thunderstorms should develop this afternoon
across portions of northeastern New England, along or ahead of the
cold front, offering isolated damaging gusts and marginally severe
hail. A zone of regionally maximized large-scale UVV -- preceding a
compact mid/upper cyclone and related shortwave trough now located
over western QC southeast of James Bay -- should spread over the
region atop a destabilizing boundary layer with diurnally minimized
MLCINH. A well-mixed boundary layer will support potential for
hail/gusts to reach the surface, beneath 500-1200 J/kg MLCAPE.
Effective-shear magnitudes around 30-40 kt will support some
storm-scale organization.

...Gulf Coast...
See tornado watch 284 and related mesoscale discussion for the
near-term tornado potential with what now is T.S. Claudette. This
highly asymmetric and strongly sheared cyclone is forecast by NHC to
turn northeastward, then east-northeastward across MS/AL through the
period. [See NHC advisories for latest specific track/intensity
forecasts and tropical watches/warnings.] The tornado potential
should remain displaced well away from the center, across those
portions of the outer eastern semicircle that can destabilize
sufficiently to support sustained supercells. That condition will
remain most probable relatively close to the coast, both in
persistent convergence/convective bands initially located over
southwestern AL and the FL Panhandle, southward over the Gulf.
Isolated discrete supercells also are possible east of the bands.

Theta-e advection and diurnal heating should destabilize the
boundary layer across the FL Panhandle, southeastern AL and perhaps southwestern GA as favorable low-level shear/hodographs spread
eastward through the outlook area. The tornado threat should
diminish this evening, both with inland/northeastward extent and
with time, as Claudette continues to gain distance from the Gulf,
flow veers to its south, and the most-favorable buoyancy and wind
profiles become more displaced from each other.

..Edwards/Broyles.. 06/19/2021

$$
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ACUS01 KWNS 200533
SWODY1
SPC AC 200532

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1232 AM CDT Sun Jun 20 2021

Valid 201200Z - 211200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN
IOWA TO SOUTHERN LOWER MICHIGAN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
ENHANCED RISK FROM THE MID MISSISSIPPI VALLEY INTO THE LOWER GREAT
LAKES ALONG WITH PARTS OF THE SOUTHEAST...

...SUMMARY...
Scattered severe storms are expected across the Midwest into the
lower Great Lakes/upper Ohio Valley. Large hail, severe/damaging
winds, and a few tornadoes are possible. Damaging winds and a couple
of tornadoes are also possible across the Southeast.

...Midwest to Lower Great Lakes...

Late Saturday central High Plains convection has spread downstream
and matured into a significant MCS as it tracks east along the NE/KS
border. Forward propagation appears to be reasonably similar to the
latest NAM with the leading edge of the MCS likely spreading across southwestern into south-central IA early in the period. One concern
is how poorly the models are handling the strong, sustained
convection across northern MO. This activity continues to propagate
northwest and will likely be absorbed into a larger complex by
daybreak. The disruptive potential of this interaction is unknown.
Even so, it appears a corridor of strong instability should evolve
from northern IL into southern lower MI. Approaching convectively
induced short-wave trough, strong heating, and the potential for a
low-level confluence zone to be draped across this region suggest
the potential for significant severe. Have opted to extend the ENH
Risk downstream across southern lower MI and adjacent portions of
northern IN/northwest OH as forecast soundings are impressively
buoyant and strongly sheared. Profiles favor supercells but the
early-day MCS will likely continue, in some form, through the day as
it spreads downstream. If supercells evolve, tornadoes and large
hail threat will increase with this activity. Otherwise, damaging
winds can be expected.

Later in the afternoon, surface heating should contribute to frontal
convection that will initiate across the upper MS Valley, then
spread/develop along the wind shift into eastern KS. Steep lapse
rates, strong surface-6km shear, and abundant instability suggest
the potential for very large hail with supercells in the wake of the
early-day MCS.

...Southeast...

Remnants of Claudette continue to shift downstream across AL into
GA/northern FL. Low-level shear will remain strong from northern FL
into coastal NC much of the period. While numerous showers/storms
will be ongoing at daybreak, latest NAM suggests a narrow corridor
of steeper surface-3km lapse rates within the zone of stronger shear
from northeast FL through coastal SC. This may increase the
potential for damaging winds and tornadoes. For these reasons have
increased severe probabilities across this region.

..Darrow/Lyons.. 06/20/2021

$$
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ACUS01 KWNS 201938
SWODY1
SPC AC 201937

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0237 PM CDT Sun Jun 20 2021

Valid 202000Z - 211200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
EXTREME EASTERN IOWA ACROSS CHICAGOLAND TO NORTHWEST OHIO AND
SOUTHERN LOWER MICHIGAN...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
ENHANCED RISK...AND ALSO OVER PARTS OF GEORGIA AND THE CAROLINAS...

...SUMMARY...
Scattered severe storms are expected across the Midwest into the
lower Great Lakes/upper Ohio Valley. Large hail, severe/damaging
winds, and a few tornadoes are possible. Damaging winds and a couple
of tornadoes are also possible across the Southeast.

...20Z Update...

...Southeast Coast...
Air mass downstream of Tropical Depression Claudette continues to
destabilize amid modest heating and ample low-level moisture. As
mentioned in MCD #1034, a couple of transient supercells may pose an
isolated risk for a tornado or two through the afternoon. The
highest conditional risk for a tornado appears to be over parts of
eastern NC during the afternoon due to the larger hodographs.
Additionally, based on recent trends and the location of center of
TD Claudette, the severe risk across southeast GA has diminished
enough to remove Slight Risk-equivalent probabilities. Isolated
threat across southern GA/northern FL merits continued inclusion of
5% wind probabilities.

...Elsewhere...
Forecast delineated outlined in the previous outlook (discussion
below) remains valid and no changes are needed.

..Mosier.. 06/20/2021

.PREV DISCUSSION... /ISSUED 1122 AM CDT Sun Jun 20 2021/

...MO to OH...
Current water vapor loop shows a convectively augmented vort max
over northern MO. New thunderstorm development has occurred in the
past couple of hours in this region, with a corridor of rapid heating/destabilization occurring to the east from northeast MO into
northern IL. Storms will likely intensify through the afternoon
along this axis, with the risk of damaging winds, large hail, and
isolated tornadoes. 12z CAM solutions differ on the handling of
this cluster, but the potential appears to exist for a longer-lived
bowing structure that would track all the way into northern OH this
evening. Please refer to MCD #1032 for short-term details.

...MN/WI/IA/IL...
Latest surface analysis shows a low over west-central MN. clearing
skies ahead of the low, along with southerly low-level winds, will
help to warm/moisten and destabilize this area by mid-afternoon. A
consensus of model guidance shows intense thunderstorm development
later today over southeast MN, southwest WI, and parts of
northern/eastern IA. Large hail and damaging winds will be possible
with these storms. A combination of remnant cloud debris and
outflow boundaries complicate the scenario, but also increase the
conditional risk of supercells and perhaps a few tornadoes this
evening. If the storms over MO do not materialize into a
longer-lived bow, then this area of storms may persist for several
hours and track eastward across the ENH risk area.

...GA/SC/NC...
The remnants of Claudette continue to affect parts of GA and the
Carolinas today, with relatively strong low-level winds from
southeast GA into southern SC. Considerable daytime heating and
ample low level moisture will provide favorable thermodynamics for a
few intense afternoon thunderstorms capable of damaging wind gusts
and a few tornadoes.

...Southeast CO into southern KS late tonight...
A surface cold front will extend from eastern CO into southern KS
tonight, providing the focus for a few evening/overnight
thunderstorms. Sufficient CAPE/shear along this zone will pose a
risk of hail in the strongest storms.

$$
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ACUS01 KWNS 171253
SWODY1
SPC AC 171252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Wed Apr 17 2024

Valid 171300Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY...

...SUMMARY...
Scattered thunderstorms capable of producing damaging winds, large
hail, and a few tornadoes should develop across parts of the Ohio
Valley and Lower Great Lakes this afternoon. Thunderstorms with
mainly a large hail threat may occur tonight over parts of the
central Plains.

...Synopsis...
An upper trough/low over the Upper Midwest this morning will
continue to move east-northeastward across the Great Lakes and OH
Valley today while gradually de-amplifying/weakening. An associated
40-60 kt mid-level jet will accompany this trough and overspread
much of the OH/TN Valleys. At the surface, a low over southeastern
MN/western WI should continue to gradually occlude through the day
in tandem with the weakening upper cyclone. An attendant cold front
will sweep eastward over the Lower Great Lakes/OH Valley through
this evening, while a warm front advances as far north as parts of
Lower MI and perhaps far western NY.

...Lower Michigan into the Ohio/Tennessee Valleys and
Mid-Atlantic...
Upper 50s to low 60s surface dewpoints are expected to be in place
ahead of the cold front late this morning/early afternoon. A
pronounced mid-level dry slot evident on water vapor satellite
imagery should aid in diurnal destabilization via a general lack of mid/upper-level cloud cover across parts of the OH Valley. As the
boundary layer gradually warms/moistens, around 1000-1500 J/kg of
MLCAPE should develop across southern Lower MI, eastern IN, and OH. Sufficiently strong low/mid-level winds will support 40-50 kt of
deep-layer shear and updraft organization. Current expectations are
for convection to develop along or just ahead of the cold front by
early afternoon, and subsequently spread quickly east-northeastward
across Lower MI, OH, and western PA through this evening. Tendency
may be for thunderstorms to quickly organize into a line, especially
across Lower MI which will be in closer proximity to the large-scale
ascent attendant to the upper trough/low. If this evolution occurs,
then severe/damaging winds would be the main threat with this
activity. Have expanded the Marginal and Slight Risks northward
across Lower MI to account for this potential.

Farther south across eastern IN and OH, forcing will gradually
become more limited, which may allow for somewhat lower thunderstorm
coverage initially. Even so, deep-layer shear will be strong enough
to support supercells, with large hail, damaging wind, and a few
tornadoes all possible. The best tornado potential may be focused
across parts of southeastern Lower MI and northern OH, in closer
proximity to the warm front and greater low-level shear. Some
upscale growth may also occur with this activity as it moves into
eastern OH and western PA, with a potentially greater threat for
damaging winds through the early evening before convection
eventually weakens.

Overall convective coverage should be lower across the TN Valley
into the Southeast, with weaker large-scale ascent present over
these regions. Still, isolated strong thunderstorms may occur this
afternoon and early evening in a weakly unstable but strong
deep-layer shear environment. Occasional hail and gusty winds appear
possible with the more robust cores. Based on latest guidance
trends, have trimmed the western extent of the Marginal Risk over
western KY/TN and northern MS.

Across the eastern Mid-Atlantic (northern VA/MD/DC/DE/south-central
PA), a well-mixed boundary layer and steep low-level lapse rates
forecast by some guidance may support occasional strong to damaging
winds with convection spreading eastward off the higher terrain of
the Appalachians and Blue Ridge Mountains. With limited instability,
the overall severe wind threat will likely remain isolated.

...Nebraska/Kansas into Iowa/Missouri...
An upper-level trough will move eastward across the north-central
CONUS tonight. A 40-45 kt southerly low-level jet will develop this
evening across parts of the southern/central Plains in response.
Thunderstorms should eventually initiate near the northern edge of
the low-level jet late this evening from central KS into far
southeast NE. Ample MUCAPE, steep mid-level lapse rates, and strong
shear in the cloud-bearing layer should support some threat for
large hail with this mainly elevated convection. The large hail
threat should to be greatest in the 04Z to 08Z time window with
initial development, but it may persist through the end of the
period. If convection can grow upscale into a small bowing cluster,
then isolated damaging winds may also occur.

A conditional threat for a supercell or two will exist farther south
across south-central/southeastern KS into far northeastern OK. Here,
modest low-level convergence along the intersection of a developing
warm front and dryline may be sufficient to initiate isolated
convection early this evening as the low-level jet strengthens. If
this occurs, then all severe hazards appear possible.

...Texas...
Very isolated thunderstorms may develop late this afternoon and
early evening across parts of south-central into central TX along a
surface dryline. If any convection can be sustained, it could
produce severe winds and hail. But, this threat currently appears
too conditional and uncertain to add low severe probabilities.

..Gleason/Bentley.. 04/17/2024

$$
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ACUS01 KWNS 191232
SWODY1
SPC AC 191231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Fri Apr 19 2024

Valid 191300Z - 201200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR PARTS OF THE SOUTHEAST...

...SUMMARY...
Sporadic strong to marginally severe storms are possible over parts
of the Southeast later today.

...Southeast this afternoon/evening...
A closed midlevel low will evolve into an open wave as it moves
eastward over the Great Lakes and OH Valley. An associated surface
cold front will continue to move slowly southeastward from TX to the
southern Appalachians. A weak lead shortwave trough (enhanced some
by overnight convection) will move eastward over the southern
Appalachians and Piedmont this morning and the eastern Carolinas by
early-mid afternoon. Isolated thunderstorms will be possible with
the lead trough farther east in the Carolinas this afternoon, with
little larger-scale forcing for ascent farther west. Still, widely
scattered thunderstorm development will be possible this afternoon
in conjunction with weak ascent along the front and local terrain
circulations across the western parts of the MRGL risk area.
Weak-moderate buoyancy, modest deep-layer shear and steepening
low-level lapse rates will support some potential semi-organized
storms capable of producing isolated wind damage and marginally
severe hail for a few hours this afternoon/evening.

...TX through tonight...
Weak upslope flow along a slow moving cold front will favor
thunderstorm development over the east slopes of the Sierra Madre Oriental/Sierra del Burro this afternoon, with the potential for a
couple of supercells. However, it is not clear that storm motions
will bring the convection across the Rio Grande, and lingering
convective inhibition suggests storms will likely weaken if they
manage to cross the border. Later tonight in northwest TX, elevated
convection will likely develop atop the frontal surface, in a warm
advection regime downstream from a weak shortwave trough over AZ/NM.
Some small hail may occur given lingering steep midlevel lapse rates
and modest cloud-layer shear, but the potential for severe hail
appears too low to warrant an outlook area.

..Thompson/Kerr.. 04/19/2024

$$
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ACUS01 KWNS 201237
SWODY1
SPC AC 201235

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0735 AM CDT Sat Apr 20 2024

Valid 201300Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
THROUGH LATE EVENING ACROSS CENTRAL/SOUTH TX...AND FROM SOUTHERN MS
TO SOUTHERN NC...

...SUMMARY...
Marginally severe storms capable of strong wind gusts and hail will
be possible mainly this afternoon/evening across portions of central
and south Texas, and from southern Mississippi to southern North
Carolina.

...TX into the Southeast this afternoon/evening...
South of a midlevel trough over the Great Lakes, a southern-stream
shortwave trough will progress eastward from southern AZ/NM toward
the lower MS Valley by Sunday morning. An associated surface
baroclinic zone from south TX into the Carolinas will move only
slowly southward through the period, providing a focus for isolated
to scattered thunderstorm development. The more widespread
convection is expected across TX near and to the north of the front,
based on proximity to the richest moisture and the southern-stream
trough.

Boundary-layer dewpoints in the 60s and surface heating in cloud
breaks will drive MLCAPE in the 1000-2000 J/kg range immediately
south of the front across the Southeast this afternoon. Vertical
shear will be relatively weak as a result of westerly wind profiles
with only modest speed increases from the low to midlevels. The
moderate buoyancy, weak vertical shear and steep low-level lapse
rates will favor isolated strong/damaging outflow gusts for a few
hours this afternoon/evening.

Richer low-level moisture (dewpoints in the lower 70s) and steeper
midlevel lapse rates will be present across south TX through this
evening. Initially elevated convection is expected to increase atop
the frontal surface from west central into central TX, and some of
this convection will approach the surface front this afternoon.
Separate surface-based thunderstorm development is also expected
along the front, and the storms will subsequently spread
east-southeastward into early tonight. Despite MLCAPE potentially
exceeding 2000 J/kg, the steeper lapse rates will be relatively high
in the profiles (above the 700 mb level), and vertical shear will
not be particularly strong. Though isolated large hail and wind
damage will be possible, along with some clustering of storms later
this afternoon into early tonight, a MRGL risk (5% hail/wind and 2%
tornado) appears to best characterize the overall severe threat in
TX.

..Thompson/Kerr.. 04/20/2024

$$
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ACUS01 KWNS 211246
SWODY1
SPC AC 211245

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Sun Apr 21 2024

Valid 211300Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING ACROSS NORTH FL/SOUTH GA...

...SUMMARY...
Isolated damaging winds near 60 mph and large hail near 1 inch
diameter will be possible for a few hours this afternoon/evening
across south Georgia and north Florida.

...North FL/south GA this afternoon/evening...
A low amplitude shortwave trough over the north central Gulf coast
will progress eastward over south GA/north FL by late afternoon, in
advance of an upstream trough over the mid MS Valley. An associated
cold front will move slowly southeastward and offshore of the
Carolinas this afternoon, and into central FL by Monday morning.
Regional 12z soundings from JAX/TLH show lingering steep midlevel
lapse rates and an associated cap which is expected to weaken from
the west by afternoon, when thunderstorm development will become
more probable with surface heating, ascent along the front, and with larger-scale ascent related to the approaching midlevel trough. The
warm sector ahead of the front across south GA/north FL will be
characterized by mid 60s dewpoints and surface temperatures ranging
from the mid 70s to lower 80s in cloud breaks by afternoon, where
MLCAPE could approach 1000 J/kg. Coincident with diurnal
destabilization, midlevel flow will increase to 50 kt with largely
straight hodographs and effective bulk shear of 35-40 kt. This
environment of moderate buoyancy and vertical shear will support the
potential for multicell clusters and/or low-end supercells capable
of producing isolated damaging gusts near 60 mph and large hail near
1 inch in diameter for a few hours this afternoon/evening.

..Thompson/Kerr.. 04/21/2024

$$
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ACUS01 KWNS 221222
SWODY1
SPC AC 221220

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0720 AM CDT Mon Apr 22 2024

Valid 221300Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ALONG THE SOUTHEAST FL COAST...

...SUMMARY...
Strong to locally severe thunderstorms, capable of marginally severe
wind gusts and hail, will be possible near the southeast Florida
coast this afternoon.

...Southeast FL coast this afternoon...
In conjunction with a midlevel shortwave trough moving over the
Southeast, a surface cold front will progress southward from central
to south FL through the day. Surface dewpoints near 70 F this
morning will likely decrease with surface heating/mixing, though
there is some uncertainty regarding the influence of morning
clouds/convection. Assuming a few cloud breaks by midday/early
afternoon, the more probable area for thunderstorm development this
afternoon will be near the southeast FL coast. This area will be
along the southern fringe of the stronger mid-upper westerlies,
where deep-layer shear/hodograph length will be sufficient for
semi-organized storms with a low-end wind/hail threat for a few
hours this afternoon.

...Elsewhere...
A midlevel trough will dig southeastward over the northern Plains
and upper Great Lakes by Tuesday morning, as an associated surface
cold front moves southeastward into the upper MS Valley and central
Plains. Isolated high-based thunderstorms may form late this
afternoon in the zone of deepest mixing along the front from
northeast CO into northwest KS, where gusty winds will be possible.
Elevated convection rooted near 700 mb is the more probable scenario
tonight atop the frontal surface from southern NE/northern KS into
southern IA/northern MO. Otherwise, weak/low-topped convection with
isolated lightning flashes will also be possible this
afternoon/evening within the midlevel cold pool over northern ND/MN.
Strong wind gusts will be possible given deep mixing and strong
synoptic flow over ND, but severe thunderstorms are unlikely.

..Thompson/Kerr.. 04/22/2024

$$
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ACUS01 KWNS 231227
SWODY1
SPC AC 231226

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0726 AM CDT Tue Apr 23 2024

Valid 231300Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON/EVENING ACROSS NORTHWEST TX...

...SUMMARY...
Isolated severe thunderstorms capable of producing large hail (2+
inch diameter) and gusts to 65 mph will be possible this afternoon
and evening across northwest Texas. Additional strong storms
producing hail up to 1 inch diameter and gusts up to 60 mph are
possible from southeast Wisconsin and northern Illinois into Lower
Michigan.

...Northwest TX area this afternoon/evening...
No appreciable changes to the prior outlook. In the wake of a
midlevel trough crossing the Great Lakes, a surface cold front will
move southward across KS/OK today, eventually stalling by tonight
across southeast OK and northwest TX. There will be sufficient
cross-Rockies flow aloft for lee cyclogenesis across eastern NM and
adjacent west central TX, which will maintain southerly low-level
flow and northward advection of a modifying western Gulf air mass
into the frontal zone by mid-late afternoon. Strong surface heating
along the west edge of the returning moisture will result in a
sharpening dryline by late afternoon, with a dryline/front triple
point likely just off the Caprock. Isolated thunderstorm
development will be most probable near the triple point after 21z,
and convection will subsequently move southeastward before weakening
by late evening. The storm environment will be characterized by
moderate buoyancy (MLCAPE of 1500-2000 J/kg), steep midlevel lapse
rates near 9 C/km, and sufficient deep-layer shear for supercells.
Isolated very large hail of 2-2.5 inches in diameter will be the
main threat, along with a few 55-65 mph outflow gusts.

...Northern IL/southeast WI/Lower MI late this afternoon/evening...
Only minor changes to the MRGL risk area in lower MI. A midlevel
trough over the upper MS Valley this morning will continue
east-southeastward over the Great Lakes by Wednesday morning. An
associated surface trough will likewise move southeastward, and this
trough will be preceded by a band of rain with minimal buoyancy.
Behind the rain band, surface heating with steepening low-level
lapse rates and cooling midlevel temperatures will support weak
surface-based buoyancy just ahead of a secondary frontal surge.
Some low-topped convection will be possible in this zone late this
afternoon through late evening from northern IL/southeast WI into
lower MI. The storms could pose a marginal hail/wind threat.

..Thompson/Kerr.. 04/23/2024

$$
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ACUS01 KWNS 241246
SWODY1
SPC AC 241245

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Wed Apr 24 2024

Valid 241300Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING
ACROSS WEST CENTRAL TX...

...SUMMARY...
Isolated large hail and damaging winds will be possible this evening
across west central Texas.

...West central TX this evening...
A midlevel shortwave trough off the southern CA coast will move
inland over southern AZ by the end of the period. Downstream,
shortwave ridging will persist over the Plains, though some increase
in westerly flow over the Rockies will contribute to lee troughing
across eastern CO/NM. The lee trough will maintain southerly
low-level flow and a gradual increase in low-level moisture to the
south of a warm front that will move slowly northward across OK and
the TX Panhandle. The moistening (boundary-layer dewpoints of 64-70
F and 100 mb mean mixing ratios of 12-14 g/kg) will occur beneath a
warm elevated mixed layer with midlevel lapse rates of 8-9 C/km,
which will drive large buoyancy (MLCAPE > 2000 J/kg) within a capped
warm sector.

The potential exception to this is along the developing dryline
across west central TX where surface heating/mixing could be deep
enough to remove convective inhibition, and isolated thunderstorm
development will be possible by this afternoon/evening. Confidence
in storm development is modest, but the environment with large
buoyancy, steep lapse rates and effective bulk shear greater than 40
kt will conditionally favor supercells capable of producing isolated
very large hail up to 2.5 inches in diameter and severe outflow
gusts of 60-70 mph. There will be an increase in low-level shear
this evening and low-level moisture will be greater compared to
yesterday, so an isolated tornado will also be possible in a narrow
time window this evening before inhibition increases and storms
weaken.

...OK into KS through tonight...
Elevated thunderstorms are ongoing over western OK in a zone of
low-midlevel warm advection and weak buoyancy likely rooted near 700
mb. Some of this convection could persist today while spreading
eastward, with a low-end hail threat. Additional elevated storms
are expected to form overnight from northeast OK into KS with
strengthening warm advection and increasing low-level moisture. A
couple of storms could produce isolated large hail the last few
hours of the forecast period.

..Thompson/Kerr.. 04/24/2024

$$
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ACUS01 KWNS 241938
SWODY1
SPC AC 241937

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0237 PM CDT Wed Apr 24 2024

Valid 242000Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE TEXAS
SOUTH PLAINS INTO THE PERMIAN BASIN...

...SUMMARY...
Isolated large hail and severe gusts will be possible this evening
from the Texas South Plains into the Permian Basin.

...20Z Update...

...TX South Plains into Permian Basin...
Forecast outlined in the previous discussion (appended below)
remains valid. Isolated thunderstorms still appear possible within
the destabilizing air mass from the TX South Plains into the Permian
Basin. Moderate buoyancy (i.e. MLCAPE from 2000 to 2500 J/kg) and
vertical shear (i.e. 0-6 km bulk shear from 40-50 kt) support the
potential for supercells within any sustained/mature convection.
Primary risk with any supercells would be large to very large hail
up to 2.5" in diameter and strong gusts up 70 mph. Tornado risk
still appears low, although non-zero given the increasing low-level
moisture and shear expected this evening.

...OK into Central/Eastern KS...
Thunderstorms are expected to develop tonight from central OK into
central and eastern KS as warm-air advection increases throughout
the warm sector. A few stronger storms capable of marginally severe
hail around 1" in diameter are possible through Thursday morning.

..Mosier.. 04/24/2024

.PREV DISCUSSION... /ISSUED 1120 AM CDT Wed Apr 24 2024/

...West central TX this evening...
Water-vapor imagery this morning shows a midlevel low/shortwave
trough west of the southern CA/Baja California coasts and it will
move into the lower CO Valley by tomorrow morning. A mid-level
ridge situated over the southern Rockies will gradually move east
over the southern High Plains today. A lee trough will become more
pronounced throughout the day and act to maintain southerly
low-level flow across much of TX south of a warm front. The warm
front initially analyzed this morning near the Red River will slowly
move northward. Late morning surface observations over the Permian Basin/Concho Valley indicate low to mid 60s dewpoints. The 12z MAF
raob showed a 7.9 deg C/km 700-500 mb lapse rate, indicative of an
elevated mixed layer.

Weak forcing for ascent at best is expected beneath the mid-level
shortwave ridge, thereby limiting potential storm coverage. Despite
the associated forcing/capping concerns, convective inhibition will
erode considerably by 21-00z. Uncertainty remains regarding storm
development, but additional heating this afternoon --perhaps delayed
a bit due to considerable low cloud cover-- will result in moderate
buoyancy (2000-2500 J/kg MLCAPE). Relatively weak but veering winds
in the low levels beneath 65-kt westerly 250-mb flow will support a
conditional threat for supercells. Deeper mixing over the Permian
Basin may be enough to overcome and lead to a couple of storms by
late afternoon/early evening along the dryline. Isolated very large
hail up to 2.5 inches in diameter and severe outflow gusts of 60-70
mph are possible. There will be an increase in low-level shear this
evening and low-level moisture will be greater compared to
yesterday, so an isolated tornado will also be possible in a narrow
time window this evening before inhibition increases and storms
weaken.

...OK into KS through tonight...
Elevated thunderstorms near the OK/KS border late this morning are
likely the result of low-midlevel warm advection and weak buoyancy
rooted near 700 mb. Some of this convection could persist this
afternoon but it is uncertain whether intensification will occur
with this activity and whether a marginal hail threat develops. The
more probable risk for elevated storms will occur tonight coincident
with strengthening warm advection and increasing low-level moisture.

$$
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ACUS01 KWNS 291254
SWODY1
SPC AC 291252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Mon Apr 29 2024

Valid 291300Z - 301200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THROUGH LATE
AFTERNOON ACROSS THE LOWER MS VALLEY...SOUTH TX...AND SOUTHEAST
LOWER MI...

...SUMMARY...
Marginally severe wind gusts and hail will be possible today across
south Texas, the lower Mississippi Valley and southeast Lower
Michigan.

...Lower MS Valley/Gulf coast today...
A midlevel shortwave trough over northwest TX/western OK will
progress eastward to the lower MS Valley by early tonight. This
wave is preceded by a large MCS now over southern LA and the
adjacent northwest Gulf of Mexico. Outflow with this convection
will continue moving southeastward through day, with some additional
storm development possible into southeast LA/southern MS on the
eastern flank of the MCS today. Surface heating in cloud breaks,
lingering midlevel lapse rates at or above 7 C/km, and
boundary-layer dewpoints of 68-72 F will contribute to moderate
buoyancy and the potential for strong updrafts along the leading
edge of the MCS. Vertical shear will not be particularly strong,
but the stronger storms will be capable of producing isolated
downburst wind damage through this afternoon.

Farther north, the residual effects of prior and ongoing convection
will be reduced lapse rates and low-level moisture, which along with
lingering clouds will tend to limit buoyancy. Thunderstorm
development will be still be possible this afternoon/evening from AR
into western TN/KY along and in advance of a weak surface front and
the midlevel trough approaching from OK. However, severe storms are
not expected as a result of both weak buoyancy and relatively weak
vertical shear.

...South TX this afternoon...
A weak front will drift southward into south TX by this afternoon,
providing a potential focus for isolated thunderstorm development.
Rich moisture, steep midlevel lapse rates and modest deep-layer
vertical shear (straight hodographs) could support isolated large
hail/wind damage if storms do form.

...Lower MI this afternoon...
A midlevel trough will continue northeastward from the upper MS
Valley to the upper Great Lakes, while an associated/weak surface
cyclone and cold front move across WI/MI this afternoon through
tonight. Southeast Lower MI will be located within the warm sector
and could have an opportunity for some surface heating/
destabilization just east of the weakening rain band from IN into
western Lower MI. MLCAPE up to 500 J/kg, steepening low-level lapse
rates and 50 kt midlevel flow support a low-end threat for wind
damage this afternoon.

..Thompson/Leitman.. 04/29/2024

$$
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ACUS01 KWNS 021247
SWODY1
SPC AC 021246

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Thu May 02 2024

Valid 021300Z - 031200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF NORTHWEST...NORTH-CENTRAL AND CENTRAL TEXAS...

...SUMMARY...
Strong to severe thunderstorms will be possible today from parts of
the Upper Midwest to the southern Plains. The greatest potential
appears to be over parts of northwest, north-central and central
Texas, where large to very large hail, severe gusts and a couple
tornadoes are possible.

...Synopsis...
In mid/upper levels, a complex cyclone -- now over southern SK and
eastern MT -- is forecast to move slowly and erratically eastward
stride the international border, orbited by several shortwaves/
vorticity lobes. The most influential of those perturbations is
apparent in moisture-channel imagery over eastern WY to northwestern
CO. This feature is forecast to strengthen and pivot to the
central/eastern Dakotas by 00Z, then across MN to northern WI and
western Lake Superior around 2Z tomorrow. Meanwhile, broad west-
southwest to southwest flow in mid/upper levels -- with mainly
convectively augmented/modified embedded perturbations -- will cover
the central/southern Plains States. MCVs are evident over western
IA, central OK and southeast TX. These should move across the
Mississippi Valley this afternoon/evening, toward the Upper Great
Lakes, Ohio Valley and Tennessee Valley, respectively.

At the surface, 11Z analysis showed a low near STJ, with cold front
across northeastern to south-central KS, the northern/western TX
Panhandle, and north-central NM. A dryline was drawn over the Llano
Estacado near the TX/NM line, southward into the western Big Bend
region. By 00Z, the low should reach western WI, with cold front
over northern IL, central MO, southeastern KS, central/southwestern
OK, to a weak low over west-central TX. The eastward-mixing dryline
will be overtaken by the cold front from north-south, with a 00Z
position from the southern low southward near DRT. By 12Z, the cold
front should reach the northeastern IN/northwestern OH region,
extending southwestward to near a PAH-LIT-DAL line, then as a
stationary to warm front west-northwestward to central NM.

...Southern Plains to western Gulf Coast...
A large area of precip and embedded areas of thunderstorms is moving
eastward across eastern OK, northeast/east TX, and western LA,
anchored by some strong thunderstorm clusters in the southeast
TX/southwestern LA area. Isolated, marginally severe hail and/or
gusts may occur for a few more hours.

Behind that activity, an outflow boundary extends across south-
central TX, the Hill Country and Concho Valley regions, to the
Permian Basin. Northward-directed warm/moist advection and theta-e
recovery will occur today over west-central/northwest TX east of the
dryline, before being intercepted by the cold front over the
northwest TX/southwestern OK region this afternoon. Farther
northeast over most of OK, severe potential will be more isolated
and conditional near the front, given the presence of partially
modified MCS-outflow air instead of a relatively undisturbed Gulf
boundary layer.

Isolated to scattered thunderstorms are expected to develop near the
dryline and along the front this afternoon, with the most favorable
parameter space, greatest low-level convergence, and densest
convective concentration for severe potential being in and near the
"slight" area. The northern rim of the residual outflow boundary
will diffuse and move into this region as well, providing a
potential low-level vorticity source that may help to offset some
flow weaknesses aloft in terms of supporting supercell organization.
30-40 kt effective-shear magnitudes are possible. Forecast soundings
reasonably indicate modest low-level flow supporting nearly straight
hodographs with both left- and right-moving cells possible. Strong
lapse rates -- generally 7.5 to 8 deg C from surface through 400 mb
-- and mid/upper 60s F dewpoints, will support a plume of 3000-4500
J/kg MLCAPE over much of northwest, west-central and south-central/
southwest TX ahead of the dryline. Large to very large hail is the
greatest concern, though storm-scale processes and boundary
interactions may favor a tornado threat as well. Upscale
aggregation of some of this convection is possible, increasing the
severe-gust potential for at least a few hours into this evening and
tonight.

...Midwest...
A band of initial convection is crossing portions of IA and
northwestern MO, ahead of the surface cold front. As this activity
moves eastward into weakly destabilizing parts of IL/WI/northern MO
through the day, some intensification may occur, resulting in
isolated damaging gusts and marginally severe hail from the
strongest segments. Behind this activity and along/ahead of the
cold front, modest destabilization (from warm advection and limited
insolation) will occur, supporting isolated to widely scattered
afternoon thunderstorm development along the front, and additional
risk of gusts/hail near severe limits. Favorable deep shear
(effective-shear magnitudes around 40-50 kt) will spread over the
area. However, limited instability is expected, with modest deep-
layer lapse rates and trajectories from convectively processed
source regions, keeping MLCAPE generally in the 500-1000 J/kg range
in a narrow prefrontal corridor. Activity should weaken in the
evening as it moves into a more-stable airmass.

..Edwards/Leitman.. 05/02/2024

$$
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ACUS01 KWNS 051251
SWODY1
SPC AC 051250

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 AM CDT Sun May 05 2024

Valid 051300Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
SOUTH TEXAS...

...SUMMARY...
Scattered strong to severe thunderstorms are possible across parts
of South Texas today. Isolated locally severe thunderstorms are
also possible across the Mid-South and upper Ohio Valley.

...Synopsis...
A substantial synoptic-scale trough has moved inland over the
Pacific Coast States and NV, anchored by a cyclone now centered near
the NV/OR border. The 500-mb low should move erratically eastward
through the period, reaching southern WY by 12Z tomorrow, with a
strong shortwave trough southward over western CO and NM.
Associated height falls will shift eastward through the
Intermountain West, Rockies, and eventually High Plains. As that
occurs, a convectively reinforced, southern-stream perturbation --
apparent in moisture-channel imagery from western OK to central/
southeast TX -- will move eastward to the lower Mississippi Valley.
An embedded MCV, initially evident over southern OK, should move
northeastward toward the Ozarks through 00Z. Another MCV may be
located over northeast TX, and should move over AR today.

At the surface, 11Z analysis showed a weak low over northwestern OH,
near a frontal triple point, with warm front arching across eastern
OH, western WV and eastern KY. This front represents the western
rim of a cold-damming airmass over the central Appalachians, and
will be slow to erode from the west as the cold front catches up
today. The cold front extended from the low across portions of northern/western KY to northern AR, to a frontal-wave low over
northeastern OK, related to the northern MCV. The front then
extended across eastern OK, and north-central/southwest TX. The
trailing part of the cold front is expected to lose definition
amidst:
1. A vast field of convective outflow air already in place across
much of central/north/east TX, OK and AR, as well as
2. Intensifying low-level warm advection on both sides late in the
period, contributing to frontolysis.

...South TX to Mid-South/lower Mississippi Valley...
A dissipating convective complex is moving eastward across portions
of LA, followed by a still-robust but mostly non-severe line of
thunderstorms over southeast TX. The trailing line may produce
isolated gusts near severe limits for a few more hours, but should
move into an airmass modified by the leading activity. Meanwhile,
the boundary layer farther north -- ahead of a belt of precip and
embedded thunderstorms now over eastern OK and the Arklatex --
should destabilize diabatically through the afternoon. That, along
with favorable low-level moisture (surface dewpoints generally in
the mid/upper 60s F), should offset modest mid/upper-level lapse
rates enough to support peak MLCAPE in the 1000-1500 J/kg range over
much of the outlook area. Scattered thunderstorms are expected --
perhaps in the form of intensification along the northeastward-
shifted leading edge of the current convection. With modest
low-level and deep shear, severe potential should remain marginal
and isolated, in the form of gusts and hail. Mesobeta-scale
mass-response effects ahead of the MCVs might help organization over
parts of the Mid-South region later today.

Farther southwest, the aggregate outflow boundary from the morning
complexes as analyzed from near HOU-COT and into northern Coahuila.
This boundary should stall, then drift northward over south-central
TX and the adjoining Rio Grande Valley today. The boundary should
focus additional thunderstorm development from midday through the
afternoon, some of which may become severe multicells or supercells
with large hail, damaging gusts and at least marginal tornado
potential. Though flow beneath the 700-mb level should be modest
(generally 5-10 kt), two factors will favor severe potential:
1. Backed flow near the boundary, with maximized low-level
vorticity, augmentation of weak ambient shear, and favorable
storm-relative low-level winds on the mesoscale.
2. Favorable buoyancy, with MLCAPE commonly 2000-3000 J/kg along
and south of the boundary, will be fostered by strong diurnal
heating, rich low-level moisture (70s F surface dewpoints) and weak
CINH.

In the absence of notable mid/upper support behind the shortwave
trough, convection may diminish rapidly through the evening, as the
boundary layer stabilizes from both nocturnal cooling and spreading
outflow air.

...Upper Ohio Valley vicinity...
Episodes of widely scattered to scattered thunderstorms are expected
to move roughly eastward across this outlook area today, with
isolated damaging (but mainly subsevere) gusts possible.
Activity will occur as weak MLCINH is breached by diabatic heating
and frontal lift. In the pocket of favorable boundary-layer air
between the warm and cold fronts, 60s F surface dewpoints should
contribute to MLCAPE in the 1000-1500 J/kg range. Glancing
influences of a northern-stream trough -- passing north of the area
from the Upper Great Lakes across northeastern ON and adjoining QC
-- will include somewhat tightened height gradients and enhanced
mid/upper winds. However, low-level flow will remain weak and
veered to southwesterly, with weak vertical shear in the lowest 500
mb. Mode therefore should be multicellular, with convection
weakening considerably as low-level instability decreases near and
after sunset.

..Edwards/Broyles.. 05/05/2024

$$
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ACUS01 KWNS 101231
SWODY1
SPC AC 101230

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0730 AM CDT Fri May 10 2024

Valid 101300Z - 111200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
FLORIDA AND SOUTHEAST GEORGIA...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHEAST STATES...

...SUMMARY...
Severe thunderstorms capable of primarily damaging winds will
continue early today across northern Florida and far south Georgia.
A few severe storms capable of producing damaging winds and hail are
also expected across the Carolinas.

...Southern Georgia/northern Florida...
A well-organized and fast-moving squall line, which had included
embedded bowing segments and periodic mesovortices, will continue east-southeastward this morning, favoring the
prior-outflow-reinforced instability gradient near the
Georgia/Florida border. Damaging winds, along with some QLCS-related
tornado risk, will remain a distinct concern prior to the MCS moving
offshore.

The most prominent severe risk should be with the early day MCS, but
some redevelopment will be possible, immediately on the MCS
southwestern flank, as well as into the afternoon with some
potential recovery ahead of the cold front. This could occur across
southeast Alabama/southwest Georgia and the Florida Panhandle.
Deep-layer shear will remain conditionally sufficient for organized
convection, and a couple stronger cells/clusters will be possible,
with a threat of isolated hail and damaging gusts.

...Carolinas...
With the early-day MCS to the south expected to move quickly
offshore during the morning, there will be some opportunity for a
corridor of moderate destabilization across part of the Carolinas in
advance of the cold front. The favorably timed shortwave trough
approaching from the northwest will support thunderstorm development
along the front, with rather strong deep-layer flow/shear supportive
of storm organization. A couple of supercells and/or small bowing
segments will be possible, including risks of large hail and
damaging wind gusts.

...South-central Texas/Edwards Plateau...
To the north of a stalled front, at least isolated elevated
convection may develop this afternoon into early evening,
particularly across the Edwards Plateau and in closer proximity to
the Rio Grande. The intensity of any such convection remains
uncertain, but elevated buoyancy may be sufficient to support a few
severe storms with large hail as the most probable risk.

...Upper Midwest/Mississippi Valley...
Low-topped convection is expected to develop across parts of
Minnesota and Wisconsin this afternoon, in association with the
shortwave trough moving southeastward across the region. Instability
will be quite weak due to limited moisture, but relatively deep
mixing and steep low-level lapse rates could support isolated
gusty/damaging winds with the strongest convection this afternoon.

..Guyer/Broyles.. 05/10/2024

$$
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ACUS01 KWNS 121952
SWODY1
SPC AC 121950

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 PM CDT Sun May 12 2024

Valid 122000Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
FROM SOUTHEAST TX TO SOUTHWEST MS...AND THIS EVENING ACROSS THE
EDWARDS PLATEAU OF TX...AS WELL AS NORTHEAST WI/SOUTHERN U.P. OF
MI...

...SUMMARY...
Large hail, locally damaging winds, and a couple tornadoes are
possible from southeast Texas into Louisiana and southwest
Mississippi through tonight. Isolated very large hail will be
possible this evening across the Edwards Plateau of Texas. Damaging
winds and large hail will be possible this evening across northeast
Wisconsin and the southern Upper Peninsula of Michigan.

...20z Update...

No changes were needed at 20z to the existing outlook.

...East TX/LA/MS...
Scattered severe thunderstorm activity is ongoing along and south of
the warm front into eastern Texas and Louisiana, with hail reports
up to 2 inches. Additional thunderstorm activity is expected to
develop through the late afternoon/evening with further severe
potential continuing late into the period. See MCD#759 for more
information.

...Edwards Plateau in TX this afternoon/evening...
Air mass recovery has been slow across the region near the Edwards
Plateau in Texas with persistent mid-level cloud cover limiting
daytime heating. CAM solutions are spread on potential for a
supercell or two to develop through the evening. RAP forecast
soundings indicate a conditional threat for very large hail and a
tornado, given strong deep layer shear and elongated hodographs with
increasing mid-level flow. Given the conditional potential for large
hail, the Slight Risk was maintained with this outlook.

A Slight Risk continues across WI/MI this afternoon through the
evening. High-based storms with damaging wind and hail will be
possible.

..Thornton/Jewell.. 05/12/2024

.PREV DISCUSSION... /ISSUED 1127 AM CDT Sun May 12 2024/

...East TX/LA/MS through early Monday morning...
A midlevel trough will move slowly eastward from CO/NM to
KS/OK/northwest TX through tonight, with only a weak surface
reflection of the midlevel trough across OK/KS. Farther south, a
warm front will make slow progress northward into southeast TX and
southern LA, though the position of the surface front will be
modulated by the effects of ongoing/slightly elevated convection
moving toward east TX. This early convection will pose a continued
threat for occasional large hail and damaging outflow gusts into
early afternoon.

By mid afternoon and through late evening, the potential for
near-surface-based storms will increase along the warm front in
southeast TX/southwest LA where low-level shear/hodograph curvature
will be sufficient for supercells with a few tornadoes. There is
some potential for a larger storm cluster to evolve from the warm
frontal storms by this evening, and storms could persist through the overnight/early morning hours as far east as MS.

...Edwards Plateau in TX this afternoon/evening...
A couple of supercells will be possible later this afternoon/evening
near the front/dryline triple point roughly in the vicinity of San
Angelo. MLCAPE > 2500 J/kg, steep midlevel lapse rates and long
hodographs will favor isolated very large hail (up to 2.5 inches in
diameter) as the main threat for a few hours into this evening.

...WI/MI this afternoon through early tonight...
The southeast fringe of the midlevel height falls and a surface cold
front will help focus thunderstorm development after about 21z, and
storms will spread southeastward through late evening/early
overnight. Afternoon surface temperatures of 75-80 F and dewpoints
of 45-52 F in WI will drive steep low-level lapse rates and SBCAPE
of 500-1000 J/kg, which combined with modest deep-layer shear will
support the potential for high-based storms capable of producing
damaging winds of 60-70 mph and large hail of 1-1.5 inches in
diameter. The convection will likely become elevated over Lower MI
by late evening/early tonight with some continued potential for
isolated large hail.

...Extreme southwest KS/southeast CO/OK Panhandle this afternoon...
Cloud breaks will allow surface heating and steepening low-level
lapse rates in the vicinity of a weak surface cyclone across extreme
southeast CO. Deep-layer shear will be weak close to the midlevel
trough, but sufficient buoyancy/minimal inhibition and a vertical
vorticity source will support the potential for a few landspouts
mid-late afternoon.

$$
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ACUS01 KWNS 141253
SWODY1
SPC AC 141252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Tue May 14 2024

Valid 141300Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHEAST STATES...

...SUMMARY...
Severe thunderstorms are possible today over parts of central and
northern Florida and southeast Georgia, with damaging gusts and a
tornado or two possible. Severe storms may also occur across
portions of the Ohio and Tennessee Valleys into the Carolina
Piedmont, as well as the central Rockies/High Plains and parts of
west Texas.

...Northern/central Florida and southern Georgia...
A well-organized quasi-linear MCS will continue across far southeast
Georgia toward southern South Carolina this morning, with at least a
localized severe risk possible. Additional development may occur
along the southwestward-trailing outflow that should modify during
the day, while other storms ongoing over the Gulf of Mexico may also
reach the central Florida Peninsula. With moderate destabilization
(2000-3000 J/kg MLCAPE) and steep lapse rates (reference 12z
observed soundings) along/south of the effective boundary, modest
low-level hodograph curvature and some elongation suggests that
embedded bowing structures and mesovortices could develop,
accompanied by a damaging gust and tornado risk. For additional
short-term details, see Mesoscale Discussion 780.

...Ohio/Tennessee Valleys to the Carolinas...
Deep-layer moisture will advect northward ahead of a meandering
surface low, beneath a nearly uncapped troposphere. As such, diurnal
heating needs only to boost surface temperatures into the lower 70s
F to initiate convection. These temperatures, along with low to mid
60s F dewpoints, will support around 1000 J/kg SBCAPE by afternoon.
Flow aloft is generally not expected to be overly strong, with
slightly curved and short hodographs likely resulting in mainly
pulse multicellular storms, although some supercells are possible
across the Tennessee Valley toward southern Appalachians. Damaging
gusts and hail will be the main threats, though a brief tornado or
two could occur.

...Central Rockies into the Central High Plains...
The approach of a low-amplitude mid-level trough, and diurnal
heating of an uncapped boundary layer, will support scattered to
numerous thunderstorms during the afternoon and evening hours. A
deep and dry boundary layer should become established by afternoon
peak heating, resulting in high-based pulse/multicell storms
capable of producing isolated severe gusts (given 7-9 C/km low and
mid-level lapse rates). A couple instances of severe hail may also
accompany storms over the central High Plains, where low-level
moisture is slightly more favorable.

...West/northwest Texas...
A narrow corridor of thunderstorm potential exists ahead of a
diffuse dryline over western Texas by afternoon peak heating, where
the dryline circulation may be strong enough to assist in the
initiation of isolated thunderstorms amid minimal CINH. Low-level
moisture will be meager, with mid 80s F surface temperatures and low
50s F dewpoints contributing to over 30 F spreads, so any storms
that develop will be high based. If/where storms develop, somewhat
elongated hodographs suggest that supercells would be the dominant
mode of convection, accompanied by an isolated severe wind/hail
risk.

...Northern New England...
An adequately unstable environment on the southern fringe of
stronger westerlies aloft could support a few strong to locally
severe storms this afternoon, potentially spanning parts of northern
New York and Vermont/New Hampshire into nearby Maine.

..Guyer/Dean.. 05/14/2024

$$
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ACUS01 KWNS 171300
SWODY1
SPC AC 171258

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 AM CDT Fri May 17 2024

Valid 171300Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHEAST...AND PARTS OF THE NORTHERN PLAINS...

...SUMMARY...
Severe thunderstorms may impact parts of the central into eastern
Gulf Coast states and portions of the northern Great Plains this
afternoon through tonight.

...Synopsis...
In mid/upper levels, a progressive, split-flow pattern will shift
eastward across the CONUS. In the northern stream, a complex trough
over western Canada and the U.S Pacific Northwest should evolve
gradually to a closed cyclone over central parts of AB and SK by the
end of the period. A basal perturbation -- evident in moisture-
channel imagery over WA -- will move eastward to western ND by 12Z
tomorrow. This feature will be preceded by 9-12 hours along a
similar path, by a weaker (yet still influential) shortwave trough
now over the northern Rockies. This perturbation should reach
western ND at or shortly before 00Z.

The main pattern split occurs around the northwest side of a
separate shortwave trough -- extending initially from the Mid-South west-southwestward across the Red River region of southern OK/north
TX, then southwestward over the Big Bend region. This trough should
shed its northeastern portion, lose some positive tilt, and reach
near a LIT-TXK-ALI line by 12Z. A strong belt of west-southwesterly
mid/upper winds will extend from the northwestern Gulf and east TX
across much of the Southeast. This flow field will host numerous
small-scale vorticity maxima (some convectively induced/magnified).

At the surface, 11Z analysis showed a wavy, quasistationary frontal
zone extending from just off the SC coast across central FL, to the northeastern Gulf, where it has been overtaken by an MCS and
accompanying outflow extending to just off the MS coastline. The
front was evident again from a weak low near ARA southwestward over
the mid/upper TX coastal waters to between MFE-LRD. The western
segment of this boundary should move southeastward through the
remainder of deep south TX by mid/late afternoon. Meanwhile, the front-reinforcing outflow boundary from the MCS should move
northward to northeastward and inland today, gradually becoming more
diffuse amidst a broad, ambient, low-level theta-e advection regime.

...Southeastern CONUS...
Ongoing convection capable of isolated severe potential includes:
1. A long-lived MCS/bow echo moving east-southeastward from the
northeastern Gulf/Apalachee Bay region across coastal northwestern
FL, mainly moving over relatively stable surface air along and north
of the front. This complex may penetrate strong to isolated severe
gusts to the surface the next 1-2 hours before weakening. See SPC
mesoscale discussion 813 for near-term details.
2. Isolated to scattered thunderstorms, elevated atop the cold pool
from the northeastern Gulf complex, with potential for isolated
severe hail for a few more hours.

Thunderstorms in the expanding warm sector, and along the front,
should pose a risk for a few tornadoes, along with large hail and
severe gusts, this afternoon into tonight. The main uncertainty at
this time is coverage, and by which preferred mechanism the greatest
lift will occur (related concepts). Warm-frontal passage and
diurnal heating will combine to destabilize the airmass inland from southwest-northeast today, with upper 60s to mid 70s F surface
dewpoints. This will yield MLCAPE in the 2000-3500 J/kg range,
beneath 45-60 kt effective-shear magnitudes, once surface-based
parcels are attained. A more-focused area of severe potential may
develop within the lengthy corridor outlooked, particularly near the inland-shifting baroclinic zone where low-level shear should be
maximized. However, mesoscale uncertainties are still too large to
introduce greater unconditional severe probabilities at this time.

...Northern Plains...
Scattered, high-based thunderstorms are expected to develop this
afternoon over the Bighorns and perhaps farther northward/
northeastward over the Plains of southeastern MT. Activity then
should sweep east-northeastward across the northern Great Plains
into the eastern Dakotas and perhaps northwestern MN tonight before
weakening. Along that swath, one or more clusters of cold-pool-
driven convection are possible, offering severe gusts.

A deep, well-mixed subcloud layer will support locally intense
downdrafts, which may also include downward momentum transfer from
strong midlevel winds, and which should be the most common in and
near the 15%/"slight" probabilities. Surface dewpoints initially
analyzed in the 40s to low 50s across the region should lower to the
mid/upper 30s and 40s today, as diurnal heating and mixing reduce boundary-layer moisture content. Nonetheless, steep low/middle-
level lapse rates will be fostered by the approaching shortwave
perturbation and surface heating. Meanwhile, remaining moisture
will support surface-based buoyancy across much of the area, with
MLCAPE 200-700 J/kg being common. At least loosely organized cold
pools should drive this activity across a broad swath of the Dakotas
before weakening tonight over or near the Red River of the North.

...South TX...
Ongoing areas of thunderstorms over south TX in the SAT-CRP-LRD
triangle, and approaching deep south TX from adjoining MX, are
moving generally east-northeastward across this region. Activity
will be capable of isolated, episodic large hail through midday,
amid favorable deep shear and elevated buoyancy, before shifting
east of the area.

..Edwards/Goss.. 05/17/2024

$$
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ACUS01 KWNS 181258
SWODY1
SPC AC 181257

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 AM CDT Sat May 18 2024

Valid 181300Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
NORTHERN FLORIDA AND THE FLORIDA PANHANDLE TO PORTIONS OF THE
SOUTHERN ATLANTIC COAST...

...SUMMARY...
The greatest severe-thunderstorm potential today appears to be from
the Florida Panhandle eastward to the southern Atlantic Coast, with
damaging gusts the main concern.

...Synopsis...
Distinct northern- and southern-stream features over nearly opposite
parts of the CONUS will continue to exert the greatest influence on severe-thunderstorm potential. In the North, a well-developed,
zonal to cyclonic mid/upper-level jet core was evident from the
coastal Northwest to the northern Plains. Some amplification in
that belt is likely overnight, as a shortwave trough digs
southeastward across the Pacific Northwest.

Downstream, a compact but strong shortwave trough -- evident in moisture-channel imagery over western ND and southeastern SK --
should move east-northeastward to southern MB and northern MN by
00Z, forming a closed 500-mb low over the Lake Winnipeg vicinity.
The attached trough should eject northeastward to northwestern ON by
12Z tomorrow. The associated surface cold front -- drawn at 11Z
over eastern MN to near FSD, EAR, GLD and PUB -- should reach Lake
Superior, northern WI, central IA, and south-central KS by 00Z,
stalling across southwestern KS into eastern CO. By 12Z, the front
should reach northern Lower MI, northern to west-central IL, and
northern MO, while moving northward as a warm front near the I-70
corridor in KS.

Meanwhile, a positively tilted mid/upper-level shortwave trough --
with several associated vorticity maxima -- was evident in
moisture-channel imagery from KY across the Mid-South to
south-central TX. The main vorticity lobe -- now over the
northeastern AR/western TN area -- should shift eastward to middle
TN by 00Z, with trough southwestward to TX shelf waters of the Gulf.
By 12Z, the trough should extend from the western Carolinas across
southern AL. The associated surface low -- analyzed at 11Z near MEM
-- should move eastward today and devolve into a weak trough. An outflow-reinforced marine front was analyzed over shelf waters off
the middle Texas Coast to just southeast of the Mississippi River
mouth to near PNS, then across southern parts of GA and SC. This
boundary should drift eastward over the north-central Gulf Coast
region and across GA.

...Southeast...
Scattered thunderstorms in clusters -- including occasional/embedded
supercells -- have been persistent this morning just offshore from
the LA/MS/AL coastline to near the western FL Panhandle, reinforcing
the marine/outflow boundary on the southern margins of that
convection. That, and persistent rainfall north of the boundary
across southeastern LA to the AL Gulf Coast, have led to decreasing unconditional severe potential over those areas.

Instead, the greatest threat today should be with the eastern/inland
extent of the loosely organized Gulf convective plume, which extends
along and north of the boundary over the FL Panhandle and southern
GA. Damaging wind will be the main concern, with a tornado or two
possible, and isolated large hail. This region should continue to
exhibit the greatest low-level moisture/instability through the day
as the convection undergoes a net eastward shift, with surface
dewpoints commonly in the 70s F, areas of cloud-tempered diurnal
heating, weak MLCINH and MLCAPE reaching the 2000-2500 J/kg range.
Deep shear will favor organized convection, with effective-shear
vectors continuing to be commonly in the 40-50-kt range -- albeit
aligned with a substantial component parallel to the main swath of
convective lift. As such, mode should remain somewhat messy,
clustered to linear, with some embedded supercell/bow structures
possible.

Elsewhere, less-organized convection (mainly due to weaker shear)
should occur near the peninsular FL Atlantic Coast, and ahead of the
midlevel vorticity lobe and surface low/trough, from the Mid-South
across the Tennessee Valley. Isolated damaging gusts and marginally
severe hail will be possible.

...Midwest...
Thunderstorms should develop from mid/late afternoon into early
evening along the cold front -- with coverage diminishing from
scattered across the Lake Superior and WI/northeastern IA regions to
widely scattered or isolated from southern IA to portions of KS.
Damaging gusts will be the main concern, though any sustained,
relatively discrete cell may rotate and produce locally large hail
as well.

Development should occur later over the MO/KS segment than farther
north, due to the presence of capping related to an EML. The
strongest flow aloft and deep shear should remain behind the surface
front, with effective-shear magnitudes generally ranging from around
45-50 kt over the MN Arrowhead to less than 30 kt over southeastern
KS. Low/middle-level lapse rates and boundary-layer moisture also
should increase with southward extent, but the opposite will be true
for deep-layer lift/forcing. A narrow corridor of favorable MLCAPE
should develop today ahead of the front, ranging from around 1000
J/kg either side of western Lake Superior to 2000 J/kg over east-
central KS. These offsetting factors and the probable quick
evolution to quasi-linear mode in northern areas -- combined with a
narrow east-west and temporal window for the most vigorous
convection before nocturnal stabilization contribute to weakening --
support keeping unconditional probabilities at marginal levels for
this update.

...Central High Plains...
Widely scattered, high-based, somewhat skeletal thunderstorms are
expected to develop over the mountains and foothills of central/
south-central CO this afternoon near the front, and move
east-northeastward over the adjoining High Plains from late
afternoon into parts of tonight. The main concern will be isolated strong-severe downbursts. Activity will be supported initially by
diurnal heating of higher terrain, with marginal but adequate
moisture to support convection at those altitudes. While strong
gusts are possible in the mountains, the activity should move atop a
deep, well-mixed subcloud layer over the downshear central High
Plains. That deep boundary layer will be characterized by nearly
dry-adiabatic lapse rates, and enough moisture to support 200-500
J/kg MLCAPE. Eastward extent of the threat is uncertain, but in
general, should diminish overnight as nocturnal stabilizing of the
near-surface profile proceeds.

..Edwards/Goss.. 05/18/2024

$$
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ACUS01 KWNS 181631
SWODY1
SPC AC 181629

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sat May 18 2024

Valid 181630Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH FLORIDA AND SOUTHERN GEORGIA...AND PARTS OF THE WESTERN GREAT
LAKES...

...SUMMARY...
The greatest severe-thunderstorm potential today appears to be from
the Florida Panhandle eastward to the southern Atlantic Coast, and
portions of the western Great Lakes region.

...North FL/South GA...
A persistent band of widespread showers and thunderstorms extends
from the FL Panhandle into southern GA. This band will sag
southward through the day, with occasional intensification along the
leading edge as daytime heating destabilizes the upstream
environment. Locally gusty/damaging winds appear to be the main
threat.

...FL East Coast...
Strong heating is occurring along the FL peninsula, where hot/humid
conditions will be present this afternoon. Westerly low-level flow
will focus a rather strong sea-breeze circulation, with most CAM
solutions suggesting scattered thunderstorm development. It is
uncertain whether the activity will be along the immediate
coastline, or offshore. However, sufficient vertical shear and CAPE
profiles indicate a risk of supercells capable of large hail and
perhaps a tornado/waterspout or two.


...Western Great Lakes into Central Plains...
A surface cold front will extend from western WI into parts of
IA/MO/KS by mid-afternoon. Scattered thunderstorms are expected to
form along the front from the MN Arrowhead southward into western
WI, with more isolated convection from there southward into the
Plains states. Forecast soundings in MI/WI/Upper MI show favorable
vertical shear profiles for a few supercell structures capable of
hail and damaging wind gusts. Therefore have added a SLGT risk area
for that scenario. From IA south, relatively weak winds in the
lowest 6km and a deep sub-cloud layer suggest outflow dominant
storms with a more marginal severe threat.

...CO/Western KS...
Model guidance and water vapor imagery show a plume of mid-level
moisture spreading into central CO. This should result in a cluster
of thunderstorms over the mountains by mid-afternoon, spreading
eastward into the Plains this evening. Inverted-v sounding profiles
and favorable westerly flow aloft will promote gusty/damaging wind
potential in some of this activity.

...MS/AL into the Carolinas...
A relatively moist and unstable air mass is in place today across
the TN Valley into the Carolinas. Little cap and pockets of daytime
heating will lead to scattered afternoon thunderstorms throughout
the region - with some potential for locally gusty/damaging wind
gusts. Areas of slightly greater focus for concern of strong storms
are 1) Ahead of the MCV currently over northern MS, and 2) an axis
from northern AL into central NC along the northern edge of slightly
stronger winds aloft.

..Hart/Jewell.. 05/18/2024

$$
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ACUS01 KWNS 191300
SWODY1
SPC AC 191258

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 AM CDT Sun May 19 2024

Valid 191300Z - 201200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN PORTIONS OF
KANSAS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EAST-CENTRAL/SOUTHEASTERN FLORIDA...

...SUMMARY...
An organized swath of severe thunderstorm wind (potential derecho)
is expected mainly across parts of Kansas this afternoon and
evening, possibly extending into northern Oklahoma. Gusts of 75-100
mph are possible, along with large hail and a few tornadoes.

...Synopsis...
A broad fetch of westerly to southwesterly flow will cover most of
the central CONUS. This will persist downstream from a synoptic-
scale trough over the Pacific Northwest that should amplify into the
Great Basin region through the period. The downstream flow field
contains several embedded shortwaves, including a convectively
generated perturbation now over parts of KS/NE. This feature should
eject northeastward over the upper Mississippi Valley this evening,
and away from the main threat area. However, an upstream shortwave
trough -- apparent in moisture-channel imagery over the Four Corners
region -- will move east-northeastward and influence convective
potential over the central Plains this afternoon and evening.

Elsewhere aloft, a persistent trough was evident across portions of
VA, the Carolinas, GA, and AL, with cyclonic flow downstream over
the southern Atlantic Coast and as far south as most of the FL
Peninsula. This trough should reach the NC/SC/GA coastlines and
northwestern FL by 00Z, and south FL by 12Z tomorrow.

The 11Z surface analysis showed a cold front from northeastern ON
across Lower MI, western IL, west-central MO and east-central KS,
where it is being overtaken by an outflow boundary arching
southwestward across south-central KS to the OK Panhandle. The
outflow boundary is expected to stall in the next few hours, then
shift northward over southern and central KS through the day. A
dryline extended from eastern CO across the western TX Panhandle to
near LBB, MAF and northern Coahuila. The dryline should mix
eastward slightly today, reaching near the KS/CO line and eastern TX
Panhandle by mid/late afternoon. Elsewhere, a weak cold front was
drawn from a low offshore from NC southwestward over northern FL,
and should move slowly southward into central FL today.

...Central Plains...
Thunderstorms are expected to develop during mid/late afternoon
behind the dryline over the eastern Raton Mesa region, as well as
along the dryline itself, and move east-northeastward to eastward
into increasing moisture and instability. As they do, some of the
activity should aggregate into clusters as smaller-scale outflows
combine and enlarge. With supportive internal feedback of an
organizing cold pool, associated forced ascent at the front and
rear-inflow jet, and supportive midlevel winds for downward momentum
transfer, as well as the residual and diurnally destabilized outflow
boundary, the overall meso-alpha-scale pattern appears quite
suitable for an organized, potentially significant-severe
convective-wind swath to result. The most probable corridor for
such growth still appears to be across KS in and near the "moderate
risk" corridor, driven by wind probabilities.

Initially separate dryline development over the northeastern TX
Panhandle and northwestern OK may blend into (or even get undercut
by outflow from) the broader event as well, after a few hours'
discrete time to its south, with a threat of large hail, locally
severe gusts and perhaps a tornado or two. Other afternoon
development, along the dryline, in the mountains of northern CO and southeastern WY, and over the Black Hills, may move east-
northeastward across a narrow moist sector and produce severe gusts
and hail into parts of the adjoining High Plains of western NE and
the Dakotas.

Near and behind the KS-to-Panhandles dryline segment, the storm-
initiation environment will be characterized by increasing
large-scale ascent and upper divergence ahead of the ejecting Four
Corners shortwave trough, as well as strong diurnal heating, mixing
and deepening of the boundary layer. Superposition of these effects
will lead to nearly 9 deg C/km lapse rates throughout the lower/
middle troposphere, supporting 2000-3000 J/kg MLCAPE just east of
the dryline. A deep subcloud layer conducive to strong-severe
downdrafts will be available to storms over western KS from the
beginning, and should support growth/merger of resultant outflows
before activity moves into greater moisture. Forced ascent of the
moist boundary layer should help to sustain the forward-propagating
complex into strengthening nocturnal MLCINH at least across eastern
KS, and perhaps into parts of the lower Missouri Valley, before it
weakens tonight.

...FL...
Scattered thunderstorms should develop this afternoon near the I-95
corridor and roughly between MIA and the Space Coast, along and
south of a weak cold front. Organized multicells and a few
supercells are possible, offering large hail and damaging to locally
severe gusts before they move offshore. An active Atlantic
sea-breeze pattern will be augmented by mid/upper support preceding
the trough aloft. Strong diurnal heating, a deep troposphere and
rich low-level moisture (with dewpoints commonly in the 70s F and
16.5-18.5 g/kg mean mixing ratios) will support 2000-3000 J/kg peak
MLCAPE. Though weak near-surface winds will limit hodograph size,
30-45 kt effective-shear magnitudes and potential boundary
interactions will support storm organization, including supercell
potential.

..Edwards/Goss.. 05/19/2024

$$
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ACUS01 KWNS 271300
SWODY1
SPC AC 271259

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 AM CDT Mon May 27 2024

Valid 271300Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
ATLANTIC SEABOARD AND NORTH/CENTRAL TX...

...SUMMARY...
Severe thunderstorms are expected today across parts of the lower
Great Lakes, Mid-Atlantic, and Southeast. More isolated severe
thunderstorms are possible this afternoon and evening across much of
central and east Texas, as well as southwest Oklahoma and the
mid/upper Mississippi Valley.

...Synopsis...
In mid/upper levels, a messy synoptic-scale trough -- accompanied by
several northern- and southern-stream shortwaves and vorticity
maxima -- will proceed eastward across ON, the upper Great Lakes,
and the Ohio/Tennessee Valleys through the period. A northern-
stream perturbation -- initially extending from Lower MI across N --
should pivot over Lake Huron and the upper Ohio Valley/lower Great
Lakes today. The southern part should reach central/eastern PA and
central NY by 00Z. Meanwhile, a strong upstream perturbation -- now
evident in moisture-channel imagery over the Dakotas -- should move southeastward to southern MN and IA by 00Z, then portions of IN/OH
around the end of the period. In the southern stream, a positively
tiled shortwave trough -- containing a string of vorticity maxima
(some convectively induced) -- will move eastward over the
southeastern CONUS.

At the surface, a well-occluded low was apparent at 11Z over
northern Lake Michigan, with occluded/cold front arching across
Lower MI, OH, the Ozarks, and north-central to west-central TX. The
front was preceded over much of the Appalachians, Southeast and
Mid-South by extensive convective outflow. By 00Z, the front should
reach western/central NY, the central/southern Appalachians, and
central LA, becoming a stationary to slow-moving warm front over north-central/northwest TX into northern NM. A dryline -- now
located near a DYS-SJT-SOA line and into northern Coahuila -- should
move only slightly eastward today while becoming more sharply
defined as moisture returns northward, to the south of the frontal
zone.

...Atlantic Seaboard to Southeast...
Ongoing complexes of strong-severe thunderstorms over portions of AL
and GA may produce continued damaging wind -- along with isolated
large hail and/or a tornado -- while moving into a favorably moist
and slowly diurnally destabilizing airmass in their path over GA.
Meanwhile, initially subsevere northeastern parts of the original
MCS that crossed the southern Appalachians also may re-intensify
over the remainder of the morning into midday. See SPC Severe
Thunderstorm Watches 331-332 and related mesoscale discussions for
near-term details.

Northern parts of this activity -- or additional thunderstorms
developing along the front of the residual pressure and theta-e
perturbations from activity that crossed the Appalachians overnight
-- may result in widely scattered to scattered thunderstorms in
clusters through at least midday over parts of the Carolinas, and
perhaps into southern VA. Meanwhile, isolated to scattered
strong-severe thunderstorms are expected to develop along/ahead of
the front during midday and through the afternoon from the
Mid-Atlantic into parts of upstate NY. Overall convective coverage
may increase northward into stronger large-scale lift and
frontal/prefrontal convergence, though low-level moisture will
generally decrease, along with diurnal heating and midlevel lapse
rates.

Surface dewpoints should range from the low/mid 70s across GA and
the Carolinas Piedmont/coastal plain (recovering behind last
evening's MCS) to the 60s over most of the rest of the outlook
corridor. Enough veering with height in the boundary layer and
related hodograph curvature exist in forecast soundings --
especially from eastern NC northward -- to support effective SRH in
the 150-300 J/kg range, with supercell potential and some tornado
threat apparent. Effective-shear magnitudes of 35-45 kt should be
common, contributing to potential for both supercells and organized
multicells in lines or clusters.

...Southern Plains...
Isolated to scattered thunderstorms are possible from north west TX southeastward across parts of LA and southern MS. Damaging gusts
and large hail are the greatest concerns. Within that corridor,
however, a conditional potential exists for isolated supercells
offering large to very large/destructive hail, especially over
north-central and parts of central TX. Given the large buoyancy
forecast, and favorable deep shear, along with weak MLCINH and
regionally maximized convergence expected with a surface low near
the front/dryline intersection, confidence has increased enough to
introduce unconditional significant-hail probabilities, upon which
the "slight" area is based.

Strong diurnal heating and decreasing EML-related capping with
eastward extent will result in progressively greater convective
potential and denser coverage along/ahead of the front this
afternoon from northwest TX to the central Gulf Coast States.
Surface dewpoints commonly in the 70s F and steep midlevel lapse
rates will support a field of 4000-5000 J/kg MLCAPE over central/
north TX south of the front, decreasing to a still favorable 2500-
3500 J/kg over southern MS. Veering of winds with height, and a
lengthy hodograph structure well-suited for hail production in any
sustained supercells -- are expected in north-central TX. Coverage
concerns linger, considering that height rises are forecast across
this region through the period, behind the synoptic trough.

..Edwards/Goss.. 05/27/2024

$$
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ACUS01 KWNS 271647
SWODY1
SPC AC 271645

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1145 AM CDT Mon May 27 2024

Valid 271630Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN
STATES AND PARTS OF TEXAS...

...SUMMARY...
Severe thunderstorms are expected today across parts of the lower
Great Lakes, Mid-Atlantic, and Southeast States. More isolated
severe thunderstorms are possible this afternoon and evening across
much of central and east Texas, as well as southwest Oklahoma and
the mid/upper Mississippi Valley.

...Eastern States/Southeast...
An initial ongoing focus for severe potential is across Georgia near
an outflow boundary and in the wake of an MCV across the Carolinas
Piedmont as of midday. Regional WSR-88D VWPs are sampling
supercell-favorable wind profiles across this region, with
additional storm development/intensification as the air mass modifies/destabilizes across Georgia/South Carolina/southeast
Alabama. Another favored zone of severe storm development, including supercells, may occur across eastern North Carolina/southeast
Virginia this afternoon near, or in the immediate wake of, the MCV,
in the presence of a very moist and strongly unstable boundary
layer.

Farther north, a broad north-south zone of severe thunderstorm
potential exists near, or more so in the immediate lee of, the
Appalachians. For additional details, see Mesoscale Discussion 1013.
Sufficient deep-layer shear and buoyancy will support potential for
both supercells and organized multicells in lines or clusters.
Damaging winds are expected to be the most common risks, but large
hail is also possible, along the potential for a couple of tornadoes regionally.

...Southern Plains including North/Central Texas...
Isolated to scattered thunderstorm development is possible across a
broad part of North/central Texas by mid/late afternoon. Large hail
and damaging winds gusts are the greatest concerns in the presence
of large buoyancy and supercell-favorable deep-layer shear. The most
probable area for potentially intense deep convection will be near
the stalled/slow-moving front and east of the dryline, including a
corridor across North Texas/Big Country into central Texas including
the Concho Valley and Hill Country vicinity. Surface dewpoints
commonly in the 70s F and steep mid-level lapse rates will support
4000-5000 J/kg MLCAPE. A few small clusters could evolve by evening.
Later tonight, additional elevated/potentially severe storms will
probably form across western/southern Oklahoma and western North
Texas to the north of the surface front.

...Midwest including Iowa/Illinois...
A clipper-type shortwave trough over southern Minnesota and northern
Iowa this morning will continue southeastward today toward the Great
Lakes. Low-level moisture (50s F surface dewpoints) and overall
buoyancy will be limited in the wake of the primary cold front
approaching the Appalachians, but adequate moisture in the presence
of steepening low/mid-level lapse rates could yield some storms
capable of strong/gusty winds and possibly some hail during the
mid/late afternoon through early evening.

..Guyer/Squitieri.. 05/27/2024

$$
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ACUS01 KWNS 290556
SWODY1
SPC AC 290555

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Wed May 29 2024

Valid 291200Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN AND CENTRAL HIGH PLAINS...

...SUMMARY...
Scattered strong storms posing a risk for severe hail and wind
appear likely across the northern and central High Plains late this
afternoon and evening. Isolated strong storms will also be possible
over parts of the southern Plains to lower Mississippi Valley, into
the middle Rio Grande Valley.

...Synopsis...
Early morning satellite imagery shows a pair of shortwave troughs
within the northern stream, one moving southeastward across the
Upper Midwest and another progressing eastward through the Pacific
Northwest. Full-latitude shortwave ridging exists between these two
features, extending from northern Mexico into central Saskatchewan.

Eastern shortwave trough is forecast to pivot more eastward as it
moves into the OH Valley before then continuing eastward throughout
the day through the northern Mid-Atlantic States. Thunderstorm
development is anticipated ahead of this system from the middle OH
Valley through the northern Mid-Atlantic and southern New England. A
damaging gust or two is possible with these storms, but a
predominantly multicellular mode and weak vertical shear is expected
to limit the overall severe coverage.

Farther west, the Pacific Northwest shortwave is expected to
continue eastward across the northern Rockies into the northern
Plains. As it does, lee troughing will sharpen across the northern
High Plains, with eventual cyclogenesis anticipated. The resultant
surface low is then forecast to track northeastward across eastern
MT and western ND late Wednesday night/early Thursday morning.
Thunderstorms are anticipated ahead of this shortwave and attendant
surface low as well as down the lee trough across the central and
southern High Plains.

...Northern Rockies into the Northern High Plains...
Afternoon thunderstorm development is anticipated ahead of the
approaching shortwave trough from southwest MT into
northwest/north-central WY and southeast MT. In this region, strong boundary-layer mixing and increasing mid-level moisture will
contribute to airmass destabilization ahead of the approaching wave.
Buoyancy will be modest, but the high-based character of the storms
could still result in strong outflow capable of producing damaging
gusts.

Afternoon thunderstorm development is anticipated ahead of the
shortwave trough as well, where strong heating, moderate low-level
moisture and low-level convergence will support convective
initiation. A relatively narrow axis of destabilization is
anticipated across the western Dakotas, where a storm could become
strong enough to produce hail and/or damaging gusts. The eastern
extent of the severe threat will be limited by diminishing buoyancy
into the central Dakotas.

...Central/Southern High Plains...
Strong heating and low-level moisture advection will support airmass destabilization across the central and southern High Plains.
Persistent low-level convergence coupled with glancing large-scale
ascent is expected to result in convective initiation by the late afternoon/early evening. Highest coverage is expected across the
central High Plains, with weakening large-scale ascent with southern
extent likely limiting coverage. Large hail is possible with initial development, but outflow-dominant storm structures are likely, with
damaging gusts as the primary risk.

...Central/Southeast TX into Lower MS Valley...
Thunderstorms may still be ongoing across central TX this morning,
supported by persistent warm-air advection across remnant outflow.
Given the weak large-scale ascent and potential presence of a
convectively generated vorticity maximum, the evolution of these
early morning storms is uncertain. Some guidance suggests there is
potential for an MCS to develop as the vorticity maximum moves into
the moist airmass across central TX. Other guidance shows
development along the northeast and southern periphery of the
vorticity maximum, but with little linear organization. Modest
westerly flow aloft atop southeasterly surface winds along with
moderate instability will favor hail and areas of strong gusts with
any mature convection. However, the uncertainty on convective
evolution and resulting coverage precludes upgrading probabilities
across the region with this outlook.

..Mosier/Barnes.. 05/29/2024

$$
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ACUS01 KWNS 311250
SWODY1
SPC AC 311248

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0748 AM CDT Fri May 31 2024

Valid 311300Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH THIS
EVENING ACROSS THE CENTRAL/SOUTHERN HIGH PLAINS...FROM SOUTHWEST TX
TO THE TX COAST...AND ACROSS THE ARK-LA-MISS...

...SUMMARY...
A few severe storms with large hail and damaging winds will be
possible this afternoon/evening across the central/southern High
Plains, from southwest Texas to the Texas coast, and across the
Ark-La-Miss.

...Central/southeast TX to the Ark-La-Miss through this evening...
An MCS that formed overnight in central TX continues to move
southeastward toward the upper and middle TX coastal plain, with
some continuing threat for at least isolated damaging winds and some
hail (mainly west end of the MCS). Other convection has formed
farther northwest atop the trailing cold pool, and these storms may
also pose an isolated large hail threat. Once the convection moves
off the upper and middle TX coast later this morning, a large
portion of TX to the north of the ongoing storms will have been
stabilized by convective overturning. Thus, have opted to remove
some of the SLGT risk area across east TX.

Farther east, lingering low-level moisture, pockets of surface
heating later today, and the approach of remnant MCVs and a midlevel
trough from the Red River Valley may support some uptick in storm coverage/intensity this afternoon from northern LA into southeastern
AR. Potentially moderate buoyancy (assuming sufficient surface
heating) and modest vertical shear could support a few
semi-organized clusters and/or weak supercells capable of producing
isolated damaging winds/large hail, and perhaps a tornado or two.

Farther west, there will be some potential for additional storm
development this afternoon/evening along the outflow boundary
trailing westward into the Edwards Plateau and Trans-Pecos. Any
storms that form in this corridor could become supercells capable of
produce isolated large hail in an environment with steep midlevel
lapse rates, moderate-strong buoyancy, and effective bulk shear in
excess of 40 kt.

...Central/southern High Plains through tonight...
In the wake of overnight convection, clouds and weak northerly
low-level flow are present across northeast CO. A weak upslope
regime will become established during the day, and cloud breaks will
allow pockets of surface heating (stronger farther south toward
southeast CO). Potentially moderate buoyancy (MLCAPE of 1000-1500
J/kg) and sufficiently long/straight hodographs will support
supercells capable of producing large hail, while damaging winds
will also be possible with any upscale growth into small clusters.
A couple of storm clusters could persist into the overnight hours
into western KS and the TX Panhandle in response to a weak low-level
jet and associated warm advection.

..Thompson/Grams.. 05/31/2024

$$
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ACUS01 KWNS 011241
SWODY1
SPC AC 011240

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 AM CDT Sat Jun 01 2024

Valid 011300Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
INTO TONIGHT FROM WESTERN NE TO WEST TX...

...SUMMARY...
Scattered severe storms, including a few supercells, are expected to
develop across the central and southern High Plains region,
including portions of the Big Bend of Texas, this afternoon. This
activity should evolve into organized clusters while spreading into
the adjacent Great Plains later in the evening. Severe wind, hail,
and perhaps a couple of brief tornadoes are the expected risks.

...Central and southern High Plains through tonight...
Several clusters of thunderstorms are ongoing this morning across
western NE, near the KS/OK border, and along the NM/TX border. Weak
low-level warm advection and/or remnant MCVs appear to be driving
this convection, though each of the clusters are likely to weaken
later this morning. In the wake of this morning convection, a
surface front will persist across western NE, with weak lee
troughing farther to the south across eastern CO/NM in response to
modest westerly midlevel flow. Scattered thunderstorms are expected
to form by mid afternoon along the surface boundaries and
immediately east of the higher terrain, and then move
eastward/southeastward onto the Plains through tonight.

The environment across southwest TX will favor splitting supercells
immediately east of the mountains, where long/straight hodographs
(with effective bulk shear 40-50 kt), steep midlevel lapse rates and
MLCAPE near 3000 J/kg will support very large hail of baseball size
(2.75 inches) or larger. Isolated severe outflow gusts will also be
possible. Farther north, a few supercells may also form across
eastern CO into western NE, where large hail up to 2-2.5 inches in
diameter will be possible. Upscale growth into a storm cluster or
two is also expected later this evening into tonight from southwest
NE into western KS and the TX Panhandle, in response to a nocturnal
low-level jet and a related increase in low-level warm advection.
Large hail will be possible with the initial storms, but the threat
should evolve more to severe outflow winds of 60-75 mph with the
upscale growth.

...South central/southeast TX into southwest LA this afternoon...
Scattered thunderstorm development is expected today along a stalled
front extending from south central TX into southwest LA. Regional
12z soundings revealed strong buoyancy along and south of the
boundary, with moderately strong westerly flow above the 500 mb
pressure level. A mix of multicell clusters and, perhaps, some weak
supercell structures will be possible, with the potential to produce
isolated large hail and wind damage. This area may need to be
monitored for a little higher wind/hail probabilities this
afternoon.

...MS/AL/TN area today...
A midlevel trough over the middle and lower MS Valley will move
slowly eastward to the TN/OH Valleys through tonight. A couple of
different storm clusters will be possible today near and just east
of the midlevel trough where the surface warm sector across
MS/AL/TN. Deep-layer vertical shear is relatively weak per regional
VWPs, but there is some low-level hodograph curvature within a warm
advection regime. Given weak-moderate buoyancy where boundary-layer
dewpoints are in the upper 60s or greater, and later pockets of
surface heating in cloud breaks, a few storm clusters may include
embedded, weakly rotating storms capable of producing a brief
tornado or two, along with isolated wind damage.

..Thompson/Grams.. 06/01/2024

$$
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ACUS01 KWNS 031257
SWODY1
SPC AC 031256

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0756 AM CDT Mon Jun 03 2024

Valid 031300Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
FOR OK/NORTH TX EASTWARD TO THE ARK-LA-MISS...

...SUMMARY...
Strong to severe thunderstorms are possible from much of the
Mississippi Valley into the Ozark Plateau and southern Plains today.
A more concentrated area of severe thunderstorm risk may become
focused across southwest and southern Oklahoma this evening into
early tonight.

...Southern Plains to the lower MS Valley through tonight...
As has been the case for the past several nights across the Great
Plains, nocturnal convection has persisted into the morning in a few
different clusters. The most substantial of these has been an MCS
with a history of 60-80 mph measured gusts earlier this morning
across southwest KS. This MCS has weakened more recently, but some
form of the convection should continue east-southeastward through
the morning toward central OK, along the north edge of the MUCAPE up
to 3000 J/kg. Confidence in the details of the MCS evolution is
low, though there is some potential for the storms to potentially
reach the Ark-La-Tex and the western half of AR by this evening, and
perhaps as far east as the Ark-La-Miss region early tonight before
the storms weaken.

Outflow trailing southwestward from these morning storms will likely
provide a mesoscale focus for supercell development this afternoon
along the stalling boundary in the vicinity of southwest OK border.
Here, rich low-level moisture (boundary-layer dewpoints in the
low-mid 70s) and surface heating will drive MLCAPE to near 5000 J/kg
with weakening convective inhibition after peak surface heating. At
least isolated thunderstorm development is expected late this
afternoon/evening near the outflow/dryline intersection (close to
the southwest OK/southeast TX Panhandle border), and storms will
subsequently move southeastward along the stalled boundary. Despite
rather modest flow aloft, an enhanced easterly component to the
low-level flow near the outflow boundary will contribute to
sufficient hodograph length/curvature for right-moving supercells.
The extreme buoyancy, sufficiently low LCL heights and some
enhancement to low-level shear along the boundary will favor the
potential for a couple of tornadoes, in addition to isolated very
large hail (up to 3 inches in diameter) and damaging gusts. These
evening storms, or additional storms associated with warm advection,
will be possible tonight across southern and central OK.

...Southern WI and vicinity this afternoon/evening...
A remnant MCV over IA will move northeastward over WI this
afternoon, atop a subtle surface front/trough and differential
heating zone. As surface temperatures warm to 75-80 F in cloud
breaks and boundary-layer dewpoints increase to 65-70 F, moderate
buoyancy (MLCAPE near 1500 J/kg) will develop in the warm sector
from eastern IA/northwest IL into southern WI. Despite some
localized enhancement to vertical shear with the remnant MCV,
deep-layer vertical shear will generally remain weak (primarily
supporting multicell clusters and low-end supercell structures).
Thus, expect a few clusters of storms capable of producing
occasional wind damage and isolated large hail of 1-1.5 inches in
diameter for a few hours this afternoon/evening.

..Thompson/Grams.. 06/03/2024

$$
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* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)

ACUS01 KWNS 041252
SWODY1
SPC AC 041251

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Tue Jun 04 2024

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
FROM THE LOWER MS VALLEY TO OK...THEN NORTHWARD ACROSS EASTERN
KS...IA AND MN...

...SUMMARY...
Scattered strong-severe storms with wind damage and large hail will
be possible this afternoon/evening from the middle Missouri Valley
to the upper Mississippi Valley. An ongoing storm cluster near the
Arklatex could persist through the day with some damaging-wind
threat, and storms will be capable of producing isolated very large
hail and severe outflow winds of 60-80 mph this evening into tonight
across Oklahoma.

...Southern Plains to lower MS Valley through tonight...
Another in a series of overnight MCSs is moving southeastward near
the Arklatex, though the bowing system appears to have weakened
prior to sunrise. The MCS is moving into an area overturned
yesterday across LA/AR, with the primary moisture/buoyancy feed into
the MCS from the south-southwest from the unstable warm sector in
TX. There will still be some potential for eventual intensification
of the storms as the low levels warm and moisten during the day, and
the stronger embedded storms could produce damaging winds.

Outflow from the morning storms will reinforce a composite outflow
boundary, though the outflow is already somewhat diffuse with west/northwestward extent. It appears that the outflow air mass
will modify through the day across OK during the day. There will be
the potential for isolated thunderstorm development later this
afternoon along the west edge of the richer moisture (near the
western OK/TX border) where MLCAPE could exceed 5000 J/kg with only
small convective inhibition. However, forcing for ascent will be
rather nebulous and storm initiation/coverage are both in question.
If storms form, there will be just enough vertical shear for
supercells capable of producing isolated very large hail, and
perhaps an isolated tornado. Confidence is greater in renewed
thunderstorm development across KS this afternoon and into OK late
this evening into early tonight, as a weak surface cold front and
associated midlevel trough will move southeastward and impinge on
the very moist/unstable warm sector. Very large buoyancy and nearly
dry adiabatic lapse rates across OK will support large/tall storms
capable of producing isolated very large hail initially, and an
increase in the threat for damaging winds (60-80 mph) as storms grow
upscale into another MCS tonight.

...Mid MO to upper MS Valleys this afternoon/evening...
A midlevel shortwave trough and associated cold front will move
eastward from NE/Dakotas to eastern KS/IA and WI by the end of the
period. The richest low-level moisture will remain farther south,
but surface heating in pre-frontal cloud breaks and boundary-layer
dewpoints in the 60s will contribute to MLCAPE of 1000-2000 J/kg.
Vertical shear will be relatively weak in the warm sector which will
primarily support multicell clusters and line segments capable of
producing occasional wind damage and marginally severe hail.

...MO/IL today...
A midlevel low over west central MO this morning will move
northeastward toward central/northern IL by this evening. Lingering
clouds will tend to slow surface heating, though cloud breaks could
allow modest destabilization and support a few strong thunderstorm
clusters capable of producing isolated strong/damaging outflow gusts
and marginally severe hail.

..Thompson/Grams.. 06/04/2024

$$
--- SBBSecho 3.20-Linux
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ACUS01 KWNS 051252
SWODY1
SPC AC 051250

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 AM CDT Wed Jun 05 2024

Valid 051300Z - 061200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FOR MN/WI...LOWER MI/IN/OH...NORTHERN
VA/MD...SOUTHERN AND EASTERN ME...AND FROM SOUTH CENTRAL TX TO
SOUTHERN MS...

...SUMMARY...
Strong storms are possible across portions of the Upper Midwest,
Great Lakes, Northeast, Mid-Atlantic, and Texas Coastal Plain to the
southern Mississippi.

...MN/WI to the Mid-Atlantic this afternoon/evening...
Gradual pattern amplification is underway, with rising heights over
the Rockies and a deepening, downstream trough from MB to the upper
Great Lakes. A primary shortwave trough will dig southeastward from
ND to WI by tonight, accompanied by cool midlevel temperatures and
steep lapse rates below the 500 mb pressure level. Surface heating
and lingering boundary-layer moisture will contribute to
weak-moderate buoyancy in an environment with sufficient westerly
deep-layer shear/hodograph length for scattered, low-topped cells to
produce isolated wind damage and marginally severe hail this
afternoon across MN/WI.

Farther east, a lead shortwave trough will move generally eastward
from IA/WI toward Lower MI and northwest OH by this afternoon. An
associated, weak surface trough/cold front will accompany the
midlevel trough into the OH Valley, which will help focus
thunderstorm development this afternoon. Pockets of surface heating
will boost afternoon temperatures to near 80 F with boundary-layer
dewpoints in the mid-upper 60s, which will support MLCAPE up to 1000
J/kg. However, deep-layer vertical shear will remain rather modest
(effective bulk shear 20-30 kt) along with poor midlevel lapse rates
around 6 C/km, which suggests that isolated wind damage with
multicell clusters will be the main threat.

Remnant, convectively enhanced midlevel troughs will move
east-northeastward from WV and AL, coincident with the diurnal
heating cycle near and east of the Appalachians. Widely scattered
storm clusters will be possible this afternoon from GA into the
western Carolinas, but poor lapse rates and weak vertical shear will
limit any severe threat. Though lapse rates will be similarly poor
into the Mid-Atlantic, there will be a zone of stronger low-level shear/hodograph curvature across northern VA/MD in advance of the
MCV approaching from WV. Here, a few weakly rotating storms could
produce isolated wind damage and a brief/weak tornado.

...TX/LA today...
An overnight MCS continues to move southeastward into east TX and
LA, though weak vertical shear has led to a cold pool dominated
system with the deeper convection trailing well north of gust front.
This MCS will likely continue to the northwest Gulf coast by late
morning and offshore by early afternoon. There will be some
potential for isolated strong/damaging outflow gusts, especially if
there is any temporary/diurnal strengthening of the storms.
However, the overall environment and convective structure suggest
that any wind threat should remain marginal. A few storms may
develop farther west this afternoon/evening along the trailing
outflow boundary in the area around DRT. Large CAPE/steep lapse
rates will support both strong updrafts and downdrafts, though weak
vertical shear will generally limit storm longevity and the
magnitude of any hail/wind threat.

...ME/NH this afternoon...
Downstream of shortwave ridging in the midlevels, a weak northwest
flow regime will persist today over northern New England. Lingering
low-level moisture, surface heating in cloud breaks southeast of the
higher terrain, and very subtle midlevel vorticity maxima will
support a few thunderstorms this afternoon across southern/eastern
ME and part of NH. MLCAPE of 1000-1500 J/kg and effective bulk
shear near 25 kt (with longer hodographs aloft) will be sufficient
for semi-organized storms capable of producing isolated wind damage
and marginally severe hail for a few hours this afternoon.

..Thompson/Grams.. 06/05/2024

$$
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ACUS01 KWNS 061216
SWODY1
SPC AC 061214

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0714 AM CDT Thu Jun 06 2024

Valid 061300Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING ACROSS WESTERN OK AND THE EASTERN TX PANHANDLE...

...SUMMARY...
Damaging gusts of 60-70 mph will be possible this afternoon/evening
across western Oklahoma and the eastern Texas Panhandle. Isolated
wind damage will be possible this afternoon from eastern New York
into the Carolinas, and isolated wind damage/hail may also occur
across the central/east central Florida peninsula.

...TX Panhandle/western OK this afternoon/evening...
In the wake of a midlevel low over the upper Great Lakes, a weak
surface cold front will drift southward from KS into northern OK and
the TX/OK Panhandles by later this afternoon/evening. Weak lee
cyclogenesis across eastern NM will induce southerly low-level flow
and northward moisture advection across TX/OK to the south of the
front. Strong surface heating and the increase in low-level
moisture will contribute to moderate buoyancy by mid-late afternoon
(MLCAPE >1500 J/kg), in an environment of steep low-level lapse
rates/deep mixing. Low-level convergence/ascent along the front
should focus thunderstorm development by mid-late afternoon from
northwest OK into the TX Panhandle, and storms will subsequently
spread southward through the evening. Moderate buoyancy, inverted-V
profiles and northwesterly effective bulk shear of 35-40 kt will
favor a mix of multicell clusters and high-based supercells capable
of producing severe outflow gusts (mainly 60-70 mph) and isolated
large hail (1-1.5 inch diameter).

...East central FL this afternoon...
The Atlantic coast sea breeze will likely be favored this afternoon
for thunderstorm development, within a weak background westerly flow
regime. Strong surface heating across the central peninsula,
boundary-layer dewpoints in the 70s, and midlevel lapse rates near 7
C/km will result in MLCAPE near 3000 J/kg with minimal convective
inhibition. Seasonally cool midlevel temperatures (-8 to -10 C at
500 mb) and the large buoyancy will support some threat for isolated
large hail (1-1.5 inches in diameter) where vertical shear is
slightly enhanced by the sea breeze. The large buoyancy will also
result in substantial water-loaded downdrafts with the potential for
isolated wind damage (55-65 mph gusts) in an environment with steep
low-level lapse rates and DCAPE > 1000 J/kg.

...NY into the Carolinas this afternoon/evening...
A pronounced midlevel trough will progress eastward from the Great
Lakes to NY/PA by this evening, and it will be accompanied by a
surface cold front and pre-frontal trough in the lee of the higher
terrain. Midlevel lapse rates in the warm sector will not be steep,
but surface heating in cloud breaks and boundary-layer dewpoints of
65-70 F will support MLCAPE of 1000-1500 J/kg by early-mid
afternoon, when storm development is expected along the surface
boundaries. There will be some increase in midlevel flow over the
surface warm sector this afternoon (30+ kt flow near 500 mb), which
will favor primarily multicell clusters and line segments capable of
producing occasional wind damage (50-60 mph gusts).

Somewhat greater storm coverage is expected in the vicinity of
eastern NY where forcing for ascent will be more focused, with more
scattered storms farther south into the Carolinas. Despite weaker
deep-layer vertical shear with southward extent toward the
Carolinas, modest enhancement of flow in the 700-500 mb layer (30+
kt) and steep low-level lapse rates will support isolated downbursts
with wind damage. Portions of this area will be re-evaluated in
later outlooks for higher wind probabilities, primarily for
sufficient cloud breaks and resultant destabilization.

..Thompson/Grams.. 06/06/2024

$$
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ACUS01 KWNS 091208
SWODY1
SPC AC 091207

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0707 AM CDT Sun Jun 09 2024

Valid 091300Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM ARKANSAS INTO PORTIONS OF THE MID SOUTH....

...SUMMARY...
Locally severe storms, capable of producing damaging wind gusts and
some hail, are possible from the Ozarks vicinity eastward across the
Tennessee Valley and Southeast. Other isolated severe storms with
severe gusts and hail will also be possible across portions of the
central High Plains and southern Plains. Isolated strong to severe
gusts may also occur over parts of the northern Intermountain region
and northern High Plains.

...AR/Northern MS/West TN/Northwest AL...
A large but weakening MCS is present this morning over
central/southern MO. The associated surface outflow boundary
extends from northwest OK into far southern MO, and should sag only
slowly southward through the day. A very moist air mass is present
from the boundary southward across much of AR and into west
TN/northern MS/northern AL with dewpoints in the upper 60s to lower
70s. Strong heating in this zone should result in afternoon MLCAPE
values of 2000-3000 J/kg. Present indication are that scattered
thunderstorms will develop in vicinity of the remnant boundary over
northern AR and track southeastward across the SLGT risk area. Low
level winds are rather weak, but strong west-northwesterly flow
aloft will promote organized multicell or a few supercell storms
capable of damaging wind gusts and hail. Activity may remain
intense into western AL during the evening before weakening in a
more stable air mass.

...Southern and Central High Plains...
A rather large upper ridge is present today over the southwest
states, with widespread mid-level moisture evident on water vapor
imagery under the ridge. Strong heating will result in scattered
afternoon thunderstorms over the higher terrain of central NM/CO/WY, propagating slowly eastward into the adjacent high Plains during the
late afternoon. Weak winds aloft will limit organization. However,
a deeply mixed boundary layer and sufficient CAPE will pose some
risk of high-based thunderstorms capable of gusty/damaging winds and
some hail.

...Northern Great Basin into MT/WY...
Scattered high-based afternoon thunderstorms are expected today from
portions of eastern OR into ID/MT/WY. This region is along the
southern fringe of stronger anti-cyclonic westerly flow, and is
characterized by inverted-v thermodynamic profiles. A few of the
storms will pose a risk of locally gusty/damaging wind and hail
through the afternoon and evening.

..Hart/Bentley.. 06/09/2024

$$
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ACUS01 KWNS 100545
SWODY1
SPC AC 100544

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1244 AM CDT Mon Jun 10 2024

Valid 101200Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL AND NORTHERN HIGH PLAINS AND ACROSS PARTS OF THE
SOUTHEAST...

...SUMMARY...
Isolated severe storms with large hail and severe wind gusts are
expected across parts of the central and northern High Plains.
Scattered strong/severe thunderstorms are also expected across
portions of the Southeast where hail/wind are possible.

...Northern/Central High Plains...

Well-defined short-wave trough is currently located over eastern
WA/OR, shifting east in line with late-evening model guidance. This
feature is forecast to advance into western MT by 12z then shift
into central MT/northwest WY by 18z before progressing into the
western Dakotas by early evening. Primary LLJ response will be
across western ND into southeast SK, though some increase is
expected into western NE during the evening. Associated surface
front will surge across much of MT by 18z, arcing back across
northwest WY. Current thinking is convection will develop along this
boundary fairly early with NAM sounding for BYG at 18z exhibiting
negligible CINH and MLCAPE on the order of 1500 J/kg. Big Horn
Mountains may be a focus for supercell initiation, though additional development is likely east of the mountains along/near the front
over northeast WY. This activity will spread east toward the Black
Hills region in response to the progressive short wave. Large hail
and damaging winds are the main threats, though a brief tornado can
not be ruled out.

...Southeast...

Seasonally deep upper trough will hold across the eastern US through
the day1 period. This flow regime will ensure modest-strong 500mb
northwesterly flow across the southern Appalachians toward coastal
SC/GA. Latest model guidance suggests strong boundary-layer heating
will be noted across southern AL/GA where surface temperatures are
expected to rise into the lower 90s by 19z. This will effectively
remove inhibition as convective temperatures are breached. Latest
HREF guidance is very aggressive developing thunderstorms within
this veered low-level flow along the frontal zone. Strong
surface-6km bulk shear favors supercells and large hail/damaging
winds are possible. In addition, there is some low risk for a brief
tornado or two where coastal boundaries are involved.

...Southern High Plains...

Scattered-numerous thunderstorms are expected to develop once again
across the southern High Plains along the front side of a weak upper
ridge. Early this morning, a multifaceted complex of storms is
ongoing from northeast NM, arcing across the TX South Plains into
the Edwards Plateau. An MCV may evolve from this complex which will
drift southeast during the day. There is some concern that robust
convection may ultimately evolve where adequate boundary-layer
heating occurs. At this time there is a bit too much uncertainty
regarding the convective debris/remnant MCS activity to introduce a
SLGT risk, but this may ultimately be warranted in later outlooks.

..Darrow/Weinman.. 06/10/2024

$$
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ACUS01 KWNS 111209
SWODY1
SPC AC 111208

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0708 AM CDT Tue Jun 11 2024

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PORTIONS OF WEST CENTRAL TEXAS...

...SUMMARY...
Scattered thunderstorms are possible across portions of Texas
centered on the Edwards Plateau. Hail and gusty winds are the
primary threats.

...West Central TX...
Morning radar/satellite imagery shows a slow-moving MCS over western
north TX, tracking slowly southeastward. This activity is
associated with a weak upper low and related low-level warm
advection over the region. An outflow boundary along the southern
flank of this MCS will likely be the focus for afternoon
thunderstorm development in a moist and moderately unstable air
mass. Storms that form will track southeastward across the SLGT
risk area, posing a risk of damaging wind gusts and some hail.

...CO/NM...
Scattered afternoon high-based thunderstorms are expected to form
over the mountains and foothills of northern NM/southern CO. These
storms will be in a deeply mixed air mass, capable of locally gusty
winds and hail for a few hours before weakening.

...Upper MS Valley...
A surface cold front will sweep eastward across the upper MS Valley
this afternoon as an upper trough currently over the Dakotas
approaches the region. Scattered showers and thunderstorms are
expected to form along/ahead of the front during the peak-heating
period. The strongest cells may pose a risk of hail and gusty
winds. But overall the risk is expected to be rather marginal.

..Hart/Bentley.. 06/11/2024

$$
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ACUS01 KWNS 141234
SWODY1
SPC AC 141232

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0732 AM CDT Fri Jun 14 2024

Valid 141300Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
PLAINS AND NORTHEAST STATES/NEW ENGLAND...

...SUMMARY...
Scattered severe storms with large hail and wind gusts of 60-80 mph
will be possible from mid-afternoon through evening along the Front
Range to the central Great Plains. Scattered strong storms with
sporadic damaging winds and isolated hail will also be possible
across the Northeast States during the afternoon to early evening.

...Central Plains including Colorado/Nebraska/Kansas...
A mid/upper-level low over the Lower Colorado River Valley early
this morning will continue northeastward, reaching the
central/southern High Plains by evening. An outflow-reinforced front
is expected to slowly shift north-northeastward across the central
High Plains through the day, with low-level southeasterly flow
maintaining a relatively moisture-rich airmass across the central
High Plains toward the Front Range.

Thinking continues to be that at least scattered thunderstorm
development is expected by mid/late afternoon across parts of
Colorado/New Mexico including the Front Range and Raton Mesa
vicinity, influenced by differential heating and the approaching
shortwave trough. Moderate buoyancy and marginally favorable
deep-layer shear (30-40 kt) will support large hail potential with
initial discrete storm development, along with some risk for a brief
tornado or two.

A tendency toward more of a clustered mode is expected with time,
as storm coverage increases. As this occurs, isolated to widely
scattered wind gusts of 60-80 mph will be possible, especially in
areas where stronger pre-storm heating/mixing occurs. A loosely
organized MCS could eventually evolve near/north of the surface
boundary, which would result in some severe-wind potential spreading
eastward across Nebraska and western/northern Kansas tonight.

...Northern High Plains/northern Rockies...
Moderate diurnal destabilization will be possible near/east of a
weak surface low across the northern High Plains, with modest
instability extending westward across parts of the northern Rockies.
Isolated to widely scattered thunderstorms will be possible by late
afternoon into the evening, with sufficient deep-layer shear to
support a few stronger storms capable of producing isolated hail and strong-to-severe wind gusts.

...Northeast/Mid-Atlantic States and New England...
A mid/upper-level trough will move across the Mid-Atlantic and New
England later today into tonight. Weak to moderate buoyancy will
develop along/ahead of a cold front, with scattered thunderstorm
development expected from Pennsylvania into New England, and more
isolated development possible farther south into parts of the
central Appalachians and Mid-Atlantic. Moderate deep-layer shear
will support some storm organization, and few stronger clusters
and/or marginal supercells will be possible, with an attendant
threat of locally damaging winds and hail.

..Guyer/Leitman.. 06/14/2024

$$
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ACUS01 KWNS 171241
SWODY1
SPC AC 171240

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 AM CDT Mon Jun 17 2024

Valid 171300Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE
NORTHERN/CENTRAL PLAINS TO THE UPPER MIDWEST/UPPER GREAT LAKES...

...SUMMARY...
Scattered strong to severe storms are expected today mainly across
the Upper Mississippi Valley, and across the central High Plains and
Northern Plains late this afternoon through tonight, with damaging
winds and large hail possible.

...Upper Mississippi Valley/Upper Great Lakes...
A modestly organized quasi-linear band of convection continues to
make a general east-northeastward progression across southeast
Minnesota into west/northwest Wisconsin around sunrise. While the
convection has trended less organized and generally less intense, strong/locally severe wind gusts have continued to occur within an
environment characterized by steep lapse rates and ample elevated
instability in vicinity of the synoptic front. Evolving MCV
influences and diurnal destabilization may allow strong/severe
storms to persist east-northeastward across central/northern
Wisconsin and perhaps Upper Michigan today, with additional
redevelopment a possibility this afternoon/early evening along the outflow-reinforced front near the Iowa/Minnesota border vicinity.
Bouts of damaging winds and severe hail are the primary hazards.

...Northern/Central Plains...
A pronounced mid/upper-level trough over the Pacific Northwest will
shift east-northeastward over the northern Intermountain region
today and reach the northern High Plains tonight. Steady surface
cyclogenesis will occur today across interior Wyoming, and
subsequently into the central High Plains in vicinity of a southwest/northeast-oriented front.

Near/south of the front, strong boundary-layer heating is expected
across the central High Plains of eastern Colorado into northwest
Kansas and southwest Nebraska. As temperatures warm into the lower
90s F, convective temperatures will be breached and isolated
supercells should develop, most probable near/east of the northeast
Colorado surface low and triple point vicinity including the Colorado/Nebraska/Kansas border region. Forecast soundings exhibit
ample MLCAPE (2500-4000 J/kg) with steep lapse rates, along with
favorable shear for sustained rotating updrafts. Very large hail may
accompany this activity and some tornado threat may also exist.
These storms are likely to persist east-northeastward and
potentially cluster/organize to a degree toward central Nebraska
this evening.

Farther north, strong dynamic forcing will encourage convection to
develop across the High Plains of northeast Wyoming and southeast
Montana immediately ahead of the surging cold front. This activity
will spread northeast ahead of the shortwave trough into the Dakotas
during the overnight hours, further aided by a substantial increase
of a south-southwesterly low-level jet. The severe threat will shift
into the upper Red River Valley late tonight.

...Lower Great Lakes/Upper Ohio River Valley...
A convective cluster/MCV moving eastward out of southeast Lower
Michigan early this morning should broadly influence additional
thunderstorm development into the afternoon, within a moderately to
strongly unstable environment regionally. Deep layer shear will be
weak (generally 25 kt or less), but steepening low-level lapse rates
and a moist/unstable air mass could allow for some stronger
pulse-type storms capable of localized wind damage this afternoon.

..Guyer/Leitman.. 06/17/2024

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ACUS01 KWNS 181247
SWODY1
SPC AC 181245

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Tue Jun 18 2024

Valid 181300Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
MISSISSIPPI VALLEY TO THE CENTRAL PLAINS...

...SUMMARY...
Scattered strong to severe storms are expected this afternoon into
evening over parts of the Upper Mississippi Valley southwestward
into the central High Plains.

...Upper Midwest/Middle Missouri Valley/Central Plains...
In the short term, a moderately organized quasi-linear segment over
far northeast Minnesota/Arrowhead could pose a localized severe risk
this morning, although overall severe potential has waned in the
predawn hours and this downward intensity trend should generally
continue as it encounters a more stable air mass downstream.

Otherwise, a prominent mid/upper-level trough over the northern High
Plains early today will continue an east-northeastward progression
over the Dakotas/northern Minnesota through tonight. While weak
mid-level height falls will extend along this corridor early, much
of the CONUS will actually experience neutral-weak height rises as
the eastern CONUS anticyclone dominates and builds west into the
Ohio Valley. This evolution will result in a notable surface low
tracking from eastern South Dakota, across northern Minnesota into
Ontario by mid-afternoon. Building surface pressures over the Plains
will force a cold front southeastward, and this boundary will serve
as the focus for potentially strong/severe convection by late
afternoon.

The strongest mid-level flow and deep-layer shear will be noted
across the upper Mississippi Valley, but adequate shear will extend
the length of the front into the central High Plains where a few
supercells are expected to develop, including west-central/southwest
Kansas, and potentially toward the Colorado/Oklahoma/Kansas border
region. The primary risk for organized and more intense updrafts
will be during the late afternoon through early evening hours when
instability will be maximized. Large hail and damaging winds are the
primary risks.

...Upper Ohio Valley to upstate New York/northern New England... Water-vapor/regional radar imagery reflect multiple widely dispersed thunderstorm clusters and MCVs regionally early today, occurring on
the western/northern periphery of a prominent upper ridge centered
over the Mid-Atlantic States and Carolinas. Surface heating will
contribute to ample destabilization across a broad portion of the
upper Ohio River Valley into upstate New York and northern New
England. Isolated to widely scattered thunderstorms will once again
develop and increase into the afternoon, influenced in some areas by
the aforementioned MCVs, with localized downbursts/strong wind gusts
regionally possible through the diurnal heating cycle.

...Lower/Middle Texas Coast...
Low-level easterly winds should strengthen tonight toward the coast
in relation to Potential Tropical Cyclone One. Current thinking is
that mini-supercell-conducive ingredients will remain focused
offshore through tonight, but this scenario will be reevaluated in
subsequent outlooks.

..Guyer/Leitman.. 06/18/2024

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ACUS01 KWNS 191244
SWODY1
SPC AC 191242

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0742 AM CDT Wed Jun 19 2024

Valid 191300Z - 201200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN HIGH PLAINS...SOUTH/SOUTHEAST TEXAS...AND MIDWEST TO NEW
ENGLAND...

...SUMMARY...
Locally strong wind gusts and hail may occur with storms over the
southern High Plains, with a couple of strong gusts also possible
across parts of the Midwest and from the Lower Great Lakes into New
England. A brief tornado or two may occur across south Texas through
tonight.

...Synopsis...
Dominant East Coast upper ridge is forecast to build west into the
Middle Mississippi Valley later today as the primary belt of
westerlies retreats north of the international border. This westward
expansion will encourage the tropical system over the western Gulf
basin to move into northeast Mexico, considerably south of the Rio
Grande Valley.

...Southern High Plains...
As convection persists while generally diminishing in overall
intensity across the Oklahoma/Texas Panhandles and northwest
Oklahoma this morning, outflows will contribute to additional
moistening with westward extend across far west/northwest Texas into
eastern New Mexico. This is where potentially severe thunderstorm
development is expected around mid/late afternoon across the Raton
Mesa vicinity southward across east-central/southeast New Mexico.
Instances of large hail and severe-caliber wind gusts will be
possible.

...Lower Great Lakes to northern New England...
While upper ridging will dominate this region, scattered convection
will once again develop from portions of the Ohio Valley
northeastward into New England, as surface temperatures warm through
the mid 80s to near 90 F. Convective temperatures will be breached
and thunderstorms should develop within a seasonally moist
environment with PW values in excess of 1.75 inches. Gusty winds are
the primary concern with this convection occurring in a weakly
sheared environment.

...South/southeast Texas...
Low-level shear will increase especially this afternoon into tonight
along the Texas Coast and inland across south Texas, along the
northern fringe of the western Gulf basin tropical system. Reference
NHC for the latest details on Potential Tropical Cyclone One, as
this feature may evolve into a tropical cyclone before it moves
inland south of the lower Rio Grande Valley. While this system will
remain at low latitudes, 850mb flow is expected to increase across
south Texas such that sustained updrafts will likely rotate. High PW
and strong low-level shear favors some risk for a tornado or two.

...Northern Missouri/eastern Iowa to southern Wisconsin...
To the east-northeast of lingering early morning convection across
northeast Kansas/northwest Missouri, cloud cover should generally
diminish today near the outflow augmented
southwest/northeast-oriented synoptic front across the region.
Potentially aided by an MCV, thunderstorms should redevelop and
intensify this afternoon as the boundary layer destabilizes, with as
much as 30 kt of effective shear maximized immediately near the
synoptic front. Isolated instances of localized wind damage could
occur.

..Guyer/Leitman.. 06/19/2024

$$
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ACUS01 KWNS 201250
SWODY1
SPC AC 201249

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Thu Jun 20 2024

Valid 201300Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTH-CENTRAL HIGH PLAINS AND NORTHEAST/NEW ENGLAND...

...SUMMARY...
Storms may produce scattered damaging wind gusts over parts of the
Northeast and New England mainly this afternoon. Scattered severe
storms are also expected over parts of the north-central High
Plains.

...Northeast States/New England...
The prominent upper anticyclone currently centered over the middle
Atlantic will gradually build westward across the CONUS today, while
some flattening of the ridge will occur over the Northeast and
especially New England. The stronger mid-level westerlies will be
located closer to the international border and across eastern
Canada, with weaker winds aloft over the lower Great Lakes into
southern New England. A surface cold front will advance south into
northern Maine, extending westward into southern lower Michigan by
midday, with subsequent southeastward movement expected across the
Northeast through early evening.

This boundary will serve as the focus for intensifying convection
later today as surface temperatures quickly soar through the 80s
into the lower 90 F, with a weak mid-level impulse/MCV near Lake
Ontario this morning being an additional influence. While deep-layer
shear will not be particularly strong in most areas, PW values are
seasonally moist with 1.5-2 inches expected, contributing to upwards
of 2000-3000 MLCAPE this afternoon particularly across upstate New
York and interior New England/southern Maine. Damaging winds will be
possible with the strongest storms this afternoon.

...North-Central Plains...
Weak mid-level height rises will occur over the central Plains
through tonight, with a belt of moderately strong west-southwesterly
flow aloft, and few embedded disturbances, from Utah/Wyoming toward
the Dakotas and Upper Midwest. Surface cyclogenesis, focused across
northeast Colorado later today, will contribute to a
north-northwestward flux of low-level moisture across the central
High Plains/eastern Wyoming and Black Hills vicinity.

Initial thunderstorm development/intensification will occur over the
mountains toward southeast Wyoming/Colorado Front Range by
mid-afternoon, with subsequent development into the nearby High
Plains this evening, in areas near/north of the surface low/triple
point and east/northeastward-extending front. Initial storm mode
should be supercellular and large hail is expected.

Aided by an early evening strengthening of a southerly low-level
jet, storms will likely consolidate and grow upscale into a possible
MCS within the warm-advection zone focused across western/northern
Nebraska and south-central/southern South Dakota. Severe wind gusts
could materialize along the leading edge of the MCS.

...Central Rockies/Four Corners Area...
While not overly moist regionally, a west-northwestward flux of
moisture and a moderately strong belt of southwesterly mid-level
flow will contribute to sustained thunderstorms, particularly from mid-afternoon through early evening. Some of these may produce
severe-caliber downbursts.

...South Texas...
Supercell/brief tornado related to Tropical Storm Alberto is
expected to continue to diminish this morning as it moves inland and
weakens over northeast Mexico.

...Central/eastern Montana...
A weak mid-level disturbance, moderately strong flow aloft, and an
adequately moist boundary layer may contribute to some
strong/locally severe storms late this afternoon and early evening,
with hail/gusty winds possible.

..Guyer/Leitman.. 06/20/2024

$$
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ACUS01 KWNS 211253
SWODY1
SPC AC 211252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Fri Jun 21 2024

Valid 211300Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN
HIGH PLAINS TO THE UPPER MISSISSIPPI VALLEY AND OVER THE FOUR
CORNERS REGION...

...SUMMARY...
Scattered strong to severe storms are expected from parts of the
northern High Plains into the upper Mississippi Valley, mainly this
afternoon and evening. Scattered strong/severe thunderstorms are
also possible across the Four Corners vicinity. A few strong storms
may occur from parts of the lower Great Lakes to southern New
England.

...Northern High Plains...
A shortwave trough will shift eastward from the Canadian Rockies
toward Saskatchewan, with southeasterly low-level flow deep into
Montana ahead of this shortwave trough. Relatively strong (40 kt)
mid-level flow will develop across central Montana as the upper
ridge flattens. Scattered robust convection should easily develop
within a flow regime favorable for supercells. Forecast soundings,
especially for central Montana, exhibit favorable deep-layer shear
with strong buoyancy and relatively low cloud bases. Scattered
supercells should evolve by early afternoon then propagate
southeastward along the instability axis toward
eastern/south-central Montana through early evening. Very large hail
and gusty winds are expected along with some tornado risk.

...Middle Missouri Valley/Siouxland to Upper Mississippi Valley...
Scattered thunderstorms persist this morning regionally in vicinity
of the convectively modified frontal zone. A mid-level impulse over Colorado/southeast Wyoming this morning will reach the Siouxland by
late afternoon and early evening, all while a south-southwesterly
low-level jet markedly intensifies after sunset. Strong diurnal
heating south of the boundary will ease CINH across the warm sector
and scattered storms are expected to develop and intensify. Updrafts
may initially develop along the cool side of the boundary but with
time surface-based storms are expected. Hail, wind, and perhaps a
couple tornadoes can be expected with supercells occurring near the
front.

...Four Corners Region...
A seasonally high PW plume will advance into the Four Corners region
as a low-latitude shortwave trough over southern California/Nevada
ejects over the Great Basin, strengthening mid-level flow across
southern Utah into southwestern Colorado. Sustained multicells and
some supercells should develop along the southern fringe of this
shortwave trough, where strong shear will support organized
longer-lived updrafts. Large hail and strong/gusty winds can be
expected, and some tornado risk may exist as well.

...Lower Great Lakes to southern New England...
Strong boundary-layer heating will once again occur across the lower
Great Lakes region into portions of southern New England, with a southward-shifting front focusing scattered convection into early/mid-afternoon. Within a moderately unstable environment,
localized wind damage will be the primary concern with the strongest
storms his afternoon through around sunset.

..Guyer/Mosier.. 06/21/2024

$$
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ACUS01 KWNS 221208
SWODY1
SPC AC 221206

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0706 AM CDT Sat Jun 22 2024

Valid 221300Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MIDWEST/GREAT LAKES...

...SUMMARY...
Severe thunderstorms are possible this afternoon and evening across
parts of the Midwest and Great Lakes region, including potential for
damaging winds as well as a risk for tornadoes.

...Midwest/Upper Mississippi Valley and Upper Great Lakes...
Ongoing scattered showers/thunderstorms near/south of the synoptic
front complicates the later-day scenario to a degree, but
outflow/air mass modification is expected into the afternoon with
moderate to locally strong destabilization. This will be also
coincident with a modestly amplifying shortwave trough/speed max
over the Upper Mississippi Valley toward the Lake Michigan vicinity.
This belt of 30-50 kt of west-southwesterly flow in the 850-500 mb
layer is expected to overspread a destabilizing environment, with
stronger insolation/destabilization most probable across eastern
Iowa into northern Illinois by mid/late afternoon.

Surface-based severe storm development including supercells will
become probable by mid/late afternoon in vicinity of the modestly
deepening surface low and triple point, including parts of northeast/east-central Iowa into far southern Wisconsin and northern
Illinois. These storms will pose a tornado risk aside from more
probable wind damage, which will increase as storms progress
southeastward and also potentially expand southwestward somewhat
along the southeastward-moving cold front this evening.

...Northern Mid-Atlantic States/Northeast...
Deep-layer wind fields and shear are likely to remain weak, but
moderately large CAPE (in excess of 2000 J/kg) may once again
develop within weak surface troughing, along and southwest of the
remnant surface frontal zone. It appears that this will become
supportive of scattered strong thunderstorms with the potential to
produce damaging wind gusts and possibly a few instances of hail.

...Northern Plains...
Stronger mid/upper forcing for ascent and mid-level cooling are
likely to remain north of the international border through and
beyond peak daytime heating, but isolated severe storms could
develop mainly across North Dakota by this evening, accompanied by a
risk for marginally severe hail and/or wind.

...Southern Arizona...
A few pulse-type strong/locally severe storms may occur this
afternoon through early evening within a relatively moist and
moderately environment across parts of south-central/southeast
Arizona, with downbursts/strong wind gusts as the primary risk.

...Eastern Utah/western Colorado...
While not expected to be nearly as active as Friday, a few strong
storms could occur regionally, with strong wind gusts/some hail
possible on a very isolated basis.

..Guyer/Mosier.. 06/22/2024

$$
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ACUS01 KWNS 241302
SWODY1
SPC AC 241300

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 AM CDT Mon Jun 24 2024

Valid 241300Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MIDWEST...

...SUMMARY...
Scattered severe thunderstorms are expected over parts of the Upper
Midwest this afternoon into tonight. Storms will be capable of large
hail, and a cluster potentially capable of destructive wind gusts
could develop over parts of Minnesota into Wisconsin.

...Upper Midwest...
A mid-level trough will continue to transition eastward and modestly
amplify over the Canadian Prairies, with southern-peripheral height
falls and strengthening westerlies from North Dakota/northern
Minnesota toward the Upper Great Lakes through tonight. In this same
corridor, a weak MCV may be evolving this morning over eastern North Dakota/northwest Minnesota, while these scattered thunderstorms will
probably also influence and somewhat hinder the effective
north-northeastward of a warm front later today across Minnesota and
Wisconsin.

A very moist (low 70s F dewpoints) and unstable air mass will
otherwise develop northeastward regionally in tandem with the warm
front as surface cyclogenesis occurs across the Siouxland and
southern Minnesota through evening. Upwards of 3000-5000 J/kg MLCAPE
is expected within the warm sector, with very warm mid-level
temperatures associated with the elevated mixed-layer plume likely
limiting warm sector development away from (south of) the immediate
triple point and cold front/warm front vicinity.

Multiple convective scenarios are possible late this afternoon
through tonight. For one, as the air mass recovers from the early
day storms, widely scattered surface-based thunderstorms may develop
by late afternoon near the eastward-advancing cold front within the
relatively narrow warm sector from far eastern North Dakota into northern/western Minnesota. Any storms that do develop will likely
organize into supercells given strong wind profiles and the large
buoyancy. Large to very large hail, damaging winds and perhaps a
tornado would be possible with any supercells, especially with
storms in proximity to the warm front.

Additionally, on the southern fringe of the early scattered early
day convection (and related cloud cover) from eastern North Dakota
into northern Minnesota, storms may form near an effective triple point/differential heating reinforced warm front. Such initial
development could occur across south-central/southeast Minnesota,
with robust instability/seasonally strong shear potentially
supportive of an initial mode of intense supercells, with subsequent
upscale growth in an MCS with heightened damaging wind potential.

Additional mostly elevated storms could form tonight from eastern
Minnesota into northern/central Wisconsin, on the immediate cool
side of the surface baroclinic gradient as a nocturnally
increasingly low-level jet heightens isentropic ascent. These storms
may also pose a large hail and damaging wind risk through the
overnight.

An upgrade to Enhanced Risk (Level 3/5) may be warranted pending
morning observational/guidance trends, potentially including a
corridor across south-central/southern Minnesota and west/southwest
Wisconsin, where a semi-focused swath of potentially significant
damaging winds appears plausible.

...Central Plains and Black Hills...
Very warm surface temperatures are expected ahead of the weakening
cold front across central Nebraska and northern Kansas. At least
isolated high-based storms are expected to develop within a
hot/deeply mixed boundary layer environment. With generally weak
mid-level flow across the region, storms may quickly become outflow
dominant, but steep low/mid-tropospheric lapse rates will support
isolated severe wind gusts. The strongest updrafts may also be
capable of producing some hail.

Other potentially severe storms will also be possible over the Black Hills/northeast Wyoming with weak low-level upslope flow in the
post-frontal environment. Modest low-level moisture and only
glancing upper-level support suggest storm coverage will remain
isolated, although severe hail/strong winds will be possible.

...Carolinas and far southeast Virginia...
At the base of departing east coast trough, subtle height falls atop
a warm and unstable air mass will support scattered afternoon
thunderstorms across much of the eastern Carolinas and far southeast
Virginia along a weak surface cold front. Enhanced flow aloft and
surface convergence near the front should be sufficient for
transient storm organization into multicell clusters or a weak
supercell. Steepening low-level lapse rates and the high PWAT air
mass will favor heavily water and hail-loaded downdrafts capable of
isolated damaging gusts. Storms should begin to move offshore by
early evening ending the severe risk.

..Guyer/Mosier.. 06/24/2024

$$
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ACUS01 KWNS 250602
SWODY1
SPC AC 250601

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Tue Jun 25 2024

Valid 251200Z - 261200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE CENTRAL PLAINS...MIDWEST AND MID MISSISSIPPI VALLEY...

...SUMMARY...
Scattered severe thunderstorms are possible across parts of the central/southern Great Plains and Midwest late this afternoon and
evening. Damaging wind gusts, large hail, and a tornado or two may
are possible.

...Central Plains and Midwest...
A complex and highly uncertain forecast scenario is likely to evolve
today, as the remnants of one or more convective clusters interacts
with a broadly moist and unstable air mass over the Midwest and
central Plains. Early in the period, an MCS may be ongoing across
parts of the southern Great Lakes and OH Valley. Near the eastern
extent of the buoyancy plume reintensification of the eastern most convection/remnants thereof appears unlikely through the morning
across the mid to upper OH Valley.

Farther west across IL and IN, any ongoing storms or remnant
outflow, should continue south and may reintensify/reinvigorate over
the mid MS Valley by mid morning. While mid-level flow decreases
with southern extent, moderate buoyancy may sustain a risk for
damaging gusts with a loosely organized cluster/MCS, potentially as
far south as the lower OH/Mid MS Valley this evening.

A greater focus for severe convection appears likely to evolve along
the slow-moving synoptic cold front drifting south across the
central Plains. Strong heating along the front ahead of a subtle
shortwave trough will allow for isolated storm development this
afternoon. Model soundings show enhanced mid and upper-level shear
profiles, along with steep mid-level lapse rates. Supercells may
evolve with an initial risk for large hail, given MLCAPE of
4000-5000 J/kg and the discrete mode. A brief tornado or two may
also be possible with enhanced vertical voritcity and low-level
shear near the front.

With time, mostly front-parallel flow will favor upscale growth into
clusters and potentially an MCS over eastern NE and IA. With
plentiful MLCAPE (2000-3000 J/Kg) in place over the region, damaging
winds will remain possible as storms track east/southeast into the
eastern central Plains and the mid MS Valley. The exact
eastern/southern extent of any severe risk remains quite uncertain,
given the tendency for storms to outrun the stronger upper-level
support. Still, a few CAM members suggest a coherent line of storms
will continue overnight reaching southern MO/IL and eastern KS
before the start of the Day2 period.

...KS OK and the TX Panhandle...
On the northern fringes of the subtropical ridge over the southern
third of the CONUS, robust diurnal heating should support very hot
daytime temperatures along and east of dryline from west-central KS,
into northwest OK and the TX Panhandle. As the western portion of
the ridge intensifies, flow aloft should gradually veer to
northwesterly as a weak mid-level perturbation traverses the
periphery of the ridge and moves out of the central Rockies. Weak
ascent should overlap with near-convective surface temps in the low
100s F during the later afternoon, supporting isolated to widely
scattered thunderstorm development along and east of the dryline.
Moderate buoyancy within the well-mixed but moist surface air mass,
along with enhanced mid and upper-level flow, will favor a mixed
mode of high-based multicell clusters and perhaps transient
supercells capable of damaging gusts and isolated hail. The
longevity of these storms is somewhat questionable, given the
tendency for weakening upper-level support and warming mid-level
temperature to the south, but at least an isolated severe risk may
persist into parts of central OK/KS into the early evening.

...Dakotas and western MN...
Behind the main synoptic front, daytime heating over residual
boundary-layer moisture should support the development of moderate
buoyancy ahead of a second weaker cold front moving out of southern
Canada. A shortwave trough over the northern Rockies is forecast to
intensify as it moves southeast into the Plains. Modest forcing for
ascent coupled with weak low-level warm advection may support
isolated storm development late in the afternoon, eventually moving
into the eastern Dakotas and western MN by early evening. Relatively
long and straight hodographs suggest the potential for a few
elevated supercells with a risk for isolated large hail.

..Lyons/Barnes.. 06/25/2024

$$
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ACUS01 KWNS 261255
SWODY1
SPC AC 261253

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0753 AM CDT Wed Jun 26 2024

Valid 261300Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE OHIO
VALLEY INTO NORTHERN MID ATLANTIC...ACROSS PARTS OF THE OZARK
PLATEAU INTO LOWER MISSISSIPPI VALLEY...AND TO THE LEE OF THE FRONT
RANGE AND SANGRE DE CRISTO MOUNTAINS...

...SUMMARY...
Clusters of thunderstorms accompanied by potentially damaging wind
gusts are possible today into tonight from the Ohio Valley into
northern Mid Atlantic, across parts of the Ozark Plateau into lower
Mississippi Valley, and to the lee of the Front Range and Sangre de
Cristo Mountains.

...Synopsis...
A strong mid/upper-level high over NM is expected to weaken somewhat
and get shunted southward by a series of low-amplitude shortwave troughs/vorticity maxima crossing the Four Corners region and
central Rockies. This will occur as a strong synoptic trough --
apparent in moisture-channel imagery over the northeastern Pacific
between 130W-135W -- approaches the Northwest Coast. The trough
should move ashore WA/BC around 06Z, accompanied by a broad, closed
cyclone centered over or near Vancouver Island. By 12Z, the 500-mb
low should reach south-central BC, with trough southward to northern
CA. In response to these developments, the downstream synoptic ridge
over the northern/central Rockies also will weaken and shift
eastward over the adjacent High Plains.

Farther downstream, northwest flow aloft will prevail over most of
the Plains States and Mississippi Valley. A shortwave trough and
MCV -- related to an ongoing convective complex moving into the
northern Ozarks region -- should pivot southeastward to the southern Appalachians and Tennessee Valley regions by 12Z tomorrow. A
northern-stream shortwave trough -- initially located over MN --
will cross the Upper Great Lakes today, reaching southern/eastern ON
and Lake Erie by 00Z. This feature may be preceded by an MCV now
evident near the Wabash River Valley and moving northeastward. By
12Z, the combined perturbation should reach ME and coastal southern
New England.

The surface chart at 11Z showed a cold front from southern QC across
Lake Huron, central Lower MI, southern WI, southern IA, northwestern
MO, southwestern KS and southeastern CO. This front is (and will
remain) preceded across much of its length west of the Mississippi
River by convective outflows. By 00Z, the front should reach
northern NY, western PA, parts of OH and western KY, northern AR and
central OK, becoming a quasistationary to warm front from there over
the northern TX Panhandle into southern CO. By 12Z, the front
should extend from coastal MA across NJ, VA, TN, AR, OK, to central
CO.

...Ozarks/Mid-South to lower Mississippi Valley...
An extensive area of convection is apparent over the northern/
western Ozarks region into northeastern OK, with ragged reflectivity
and satellite presentation, but strong surface pressure/theta-e
deficits, and lingering areas of enhanced rear inflow above the
surface. Occasional damaging to severe gusts are possible with this
activity as it proceeds southward through eastern OK and AR into the
afternoon. See SPC Severe Thunderstorm Watch 463 and accompanying
mesoscale discussions for latest near-term guidance.

Some re-intensification or new development associated with this
convectively generated perturbation may occur as associated
low-level forcing impinges on a diurnally heating/destabilizing and
very moist air mass it its path. Any such activity will pose a
threat for strong-severe gusts across at least parts of AR and
eastern OK, and the ArkLaMiss region -- perhaps persisting
southeastward toward the Gulf Coast. Additional development is
possible (but still not certain) from late afternoon into tonight,
near or even just behind the outflow boundary from the morning
activity over AR and eastern OK. A few convection-allowing model
solutions that develop a second MCS out of such a regime move it
southwestward around the ridge toward east or even parts of
north-central TX, which is a reasonable (albeit conditional)
potential, given the ambient flow and high-theta-e potential inflow
airmass along such a track. The marginal unconditional outlook, and
to some extent the slight risk, have been expanded in that direction
on such a convective contingency. Should confidence further
increase in later outlooks, so would unconditional probabilities.

...Upper Ohio Valley to northern Mid-Atlantic...
Scattered thunderstorms are expected by mid/late afternoon over a
broad swath of the Ohio Valley region into the central Appalachians, shifting/expanding eastward across the northern Mid-Atlantic region
with time this evening. Scattered damaging gusts are expected, some
of which may be severe in magnitude (50+ kt).

Activity is expected to develop amidst weak MLCINH along/ahead of
the surface cold front, as well as near prefrontal surface trough(s)
and outflow/differential-heating boundaries. Development will be
supported by strengthening large-scale ascent ahead of the shortwave
trough and ejecting MCV, which should increase poor antecedent
midlevel lapse rates somewhat. Low-level lapse rates will be
steepened by daytime heating. That, along with favorable moisture
with 60s F surface dewpoints being common, will contribute to a
field of 500-1200 J/kg peak/preconvective MLCAPE across the outlook
area. Though low-level shear will be limited by near unidirectional
deep-layer flow and lack of stronger boundary-layer winds, deep
shear will increase enough ahead of the trough aloft to support
organized convective bands and clusters offering localized
strong-severe wind swaths, as well as pulse severe from
predominantly multicellular structures.

...Central/southern High Plains...
Isolated to scattered thunderstorms are expected to develop by late
this afternoon, and continuing into early evening, along the eastern
rim of the higher terrain from southeastern WY to northeastern NM.

Difluent northwest flow and weak large-scale lift in mid/upper
levels will prevail by the afternoon convective period, ahead of the
central Rockies/Four Corners perturbations. This should help to
maintain steep lapse rates in the overlying EML, while diurnal
heating/mixing strongly destabilize a deepening boundary layer.
Orographic and thermal lift will initiate the convection, which
should move eastward to southeastward over the High Plains, offering
sporadic severe gusts and large hail. Though modest low/middle-
level flow is expected area-wide, considerable veering of winds with
height will yield favorable deep shear for organized multicells,
and, in about the northern half of the area, isolated supercells.
Forecast soundings suggest effective-shear magnitudes varying from
less than 20 kt across the CAO/DHT region (where hot, very deep
subcloud layers are expected) to about 45-50 kt near BFF (still
well-mixed thermally), along with surface dewpoints remaining
generally in the 50s F even through the mixing cycle. This should
support wind/hail potential with the most vigorous cells, until
activity moves into nocturnally cooling lower elevations and weakens
tonight.

...Southern ID to northern Rockies...
Widely scattered thunderstorm development is anticipated this
afternoon, as increasing large-scale ascent and mid/upper flow
preceding the mid/upper-level trough superimpose a well-heated,
deeply mixed boundary layer over and near the Snake River Plain of
southern ID. Some of this activity may carry over from the isolated dry-thunderstorm areas of southeastern OR forecast in the SPC fire-
weather outlook. Convection will encounter increasing moisture/
buoyancy as it moves northeastward, but should remain over favorably high-DCAPE, strongly mixed subcloud layers with inverted-v
thermodynamic profiles, beneath around 200-800 J/kg MLCAPE. This
will support localized strong-severe wind potential, until moving
past higher mountains and into evening diabatic
cooling/destabilization.

..Edwards/Mosier.. 06/26/2024

$$
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ACUS01 KWNS 281248
SWODY1
SPC AC 281247

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0747 AM CDT Fri Jun 28 2024

Valid 281300Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
CENTRAL PLAINS INTO PARTS OF THE MIDDLE AND UPPER MISSISSIPPI
VALLEY...

...SUMMARY...
Large hail, damaging wind and a few tornadoes will be possible from
parts of the central Plains into parts of the Middle and Upper
Mississippi Valley today and tonight.

...Synopsis...
The main mid/upper-level perturbation influencing convective
potential this period is a strong shortwave trough accompanying a
small cyclone now centered over southwestern SK. The cyclone is
expected to open up today, with a 00Z trough position from
southwestern MB southwestward across northern/western ND to
northeastern WY. The trough should accelerate eastward across the
remainder of the Dakotas and MN overnight, reaching WI and Lake
Superior by 12Z tomorrow. This will occur as a closely following
shortwave digs southeastward across southern MB toward northwestern
MN. The subtropical ridge will build across the Southeast, southern
Plains and into parts of the Desert Southwest. Despite rising
absolute height values, this will yield a tightening height gradient
across the central Great Plains between the ridge and the
northern-stream trough.

The 11Z surface analysis showed a low over eastern ND, with cold
front extending across eastern SD, central NE, northwestern KS, and east-central CO. A surface trough was drawn from a cold-frontal
intersection over central NE south-southwestward to the southern
High Plains. The low should cross the Boundary Waters region of the
MN/ON border this afternoon through 00Z, when the cold front should
extend to southern MN, southeastern NE, through a weak frontal-wave
low over central/north-central KS, to southwestern KS, becoming a
diffuse warm front over eastern CO. By 12Z, the low should reach
that portion of ON northeast of Lake Superior, with cold front to
eastern Upper MI, Lake Michigan, southeastern WI, then near a line
from DVN-MKC-ICT-DHT.

...Central Plains to Mississippi Valley...
This severe-risk area is a composite of two separate potential
convective episodes, with the western (second) potentially lasting
long enough and far enough east to overlap into the hours-earlier
starting region of the first.

1. Lower Missouri Valley, eastern NE/northern KS eastward:
An extensive area of clouds and precip, with isolated to widely
scattered, embedded, non-severe thunderstorms, was apparent in radar
composites and satellite imagery from astern MN and WI across parts
of IA, northern/western MO and eastern KS. Although this will delay substantial diurnal heating across much of the mid/upper Mississippi
and lower Missouri Valley regions, sufficient destabilization (from
diabatic heating and warm advection) is expected by midafternoon to
support surface-based development near the cold front. Favorable
low-level moisture (dewpoints in the upper 60s to low 70s F) will
support a prefrontal plume of MLCAPE in the 2000-3500 J/kg range.

Modest low-level flow will limit ambient hodograph size, but
sufficient deep shear will exist (effective-shear magnitudes 35-45
kt) to support both supercells and organized multicells. Backing of
winds along and just north of the front also will enlarge hodographs
in a narrow corridor, with vorticity from the boundary potentially
ingested into favorably positioned updrafts for locally boosted
tornado potential. Development should be most likely and dense near
and northeast of the frontal-wave low, south of which low-level lift
will weaken amid rising heights aloft, and buoyancy will decrease
toward the OK border. As such, probabilities for this lobe of the
outlook area have been tightened northward somewhat. Still, upscale coalescence into one or more clusters/lines should occur, with
severe wind the greatest threat this evening into tonight, and a
tornado or two possible.

2. Central High Plains and eastward:
Widely scattered to scattered thunderstorms are expected this
afternoon over higher terrain of western/central CO, with additional
initiation possible on the foothills, Cheyenne Ridge and Palmer
Divide. This convection will be supported by sustained diurnal
heating and related weakening of MLCINH, along with moist advection
and upslope lift by the easterly component of post-frontal flow.
That moist advection also should offset moisture loss from vertical
mixing enough to maintain buoyancy, with MLCAPE in the 250-800 J/kg
range. A deep subcloud mixed layer with steep lapse rates will
encourage strong-severe downdrafts.

Though weak, low-level flow will veer with height, leading to long
hodographs and contributing to effective-shear magnitudes ranging
from around 30 kt in the southwestern part of the outlook (where
coverage also is more uncertain but conditional severe potential
still apparent) to 45-50 kt over and downshear from the Cheyenne
Ridge. As such, a high-based mix of multicells and supercells is
possible, offering mainly damaging gusts and large hail (each with
some significant severe possible). One or more clusters may evolve
and move eastward to southeastward over KS this evening and
overnight, with severe gusts the main concern.

..Edwards/Kerr.. 06/28/2024

$$
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ACUS01 KWNS 291251
SWODY1
SPC AC 291249

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0749 AM CDT Sat Jun 29 2024

Valid 291300Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEAST...AND OVER THE RATON MESA AND NEARBY SOUTH-CENTRAL HIGH
PLAINS...

...SUMMARY...
Damaging thunderstorm gusts and a few tornadoes are possible today
over parts of the Lower Great Lakes to upper Ohio Valley, while
severe gusts also may be focused this afternoon and evening over the
Raton Mesa and nearby south-central High Plains.

...Synopsis...
Broadly, the upper-air pattern will be characterized by a synoptic
trough moving ashore from the Pacific and over the West Coast
States, the downstream ridge moving slowly out of the northern/
central Rockies onto the adjoining High Plains, and troughing over
the Great Lakes and vicinity. Meanwhile, strong subtropical ridging
will prevail across the Southeast, southern Plains, and NM.

A northern-stream shortwave trough -- evident in moisture-channel
imagery over northeastern MN -- will eject east-northeastward today
and weaken, while effectively replaced by an upstream perturbation
now over portions of ND/MB. The resulting shortwave trough should
proceed eastward across the Upper Great Lakes to Lake Huron and
adjoining parts of ON by 12Z tomorrow. To its south and southeast,
a belt of strong, cyclonically curved flow will cover the mid/upper
Ohio Valley and Northeast, with minor embedded perturbations (some
convectively generated upstream from prior/overnight activity).

At the surface, the 11Z analysis showed a low over central Lake
Superior, with cold front across central Upper MI, southern WI,
southern IA, central KS, and north-central NM. By 00Z, the cold
front should move to northern IN, central IL, southern MO, northern
OK, the northern TX Panhandle, and northeastern/central NM. By 12Z,
the front should extend from western parts of NY/PA across KY, the
MO Bootheel area, and northern AR, becoming quasistationary over central/western OK, the central TX Panhandle, and east-central NM.
A prefrontal surface trough should shift eastward from the St.
Lawrence Valley/Lower Great Lakes across the northern Appalachians
and northern Mid-Atlantic States through the period.

...Northeast/Ohio Valley/Great Lakes...
Scattered thunderstorms are expected to form episodically from
midday through afternoon -- predominantly ahead of the surface cold
front. Frontal convection over parts of Lower MI also is possible
this afternoon, with isolated severe hail/gusts. The main severe
threat, however should be over parts of the Lower Great Lakes/upper
Ohio Valley into nearly Appalachians.

With weak capping, activity may form on a variety of foci, near the
main surface trough, outflow boundaries from morning clouds/precip,
and over areas of differential heating and orographic lift.
Activity should organize into one or more lines with embedded
supercells and bowing/LEWP segments possible. The main threat will
be damaging to severe gusts in and near the 15%/"slight" area,
though any supercells or embedded QLCS vortices also will pose a
tornado threat.

Despite weak mid/upper-level lapse rates over most of this region,
warm-sector moisture will be characterized by mid 60s to lower 70s F
surface dewpoints. This will combine with pockets of sustained
surface heating to yield MLCAPE in the 1000-2000 J/kg range.
Veering and strengthening of winds with height in low levels should
yield enlarged hodographs below 3 km, with effective SRH in the
150-250 J/kg range overlapping areas of favorable heating in some
parts of the upper Ohio Valley area into central PA. Little speed
shear is apparent from the top of the boundary layer into the
mid/upper levels, however, limiting deep shear, and storm structure
may become messy rather quickly. Overall, convection should weaken
as it approaches the Atlantic Coast this evening, and the foregoing
inflow layer becomes more stable.

...South-central Rockies/High Plains...
Isolated to scattered thunderstorms are forecast to develop this
afternoon over higher terrain from the southern Front Range area
across the Sangre de Cristos and Raton Mesa. This will occur as
strong heating of higher terrain preferentially erodes MLCINH, in
the presence of post-frontal upslope flow in low levels, and related
moisture advection to at least partially offset moisture loss due to
mixing. The easterly component also should aid storm-relative
boundary-layer flow and deep shear for activity propagating eastward
off the elevated terrain, with a mix of multicells and transient
supercells possible.

Despite modest low/middle-level wind speeds, forecast soundings
reasonably depict enough veering with height to yield 35-45-kt
effective-shear magnitudes, amidst 500-1500 J/kg MLCAPE and steep boundary-layer lapse rates. Some of the resulting convection may
coalesce into a complex of thunderstorms with a cold pool, in turn
driving eastward-directed forward propagation near the post-frontal
moist axis and across parts of southeastern CO, northeastern NM, the
adjacent Panhandles, and or southwestern KS, with a relatively
focused threat of severe gusts.

...Ozarks/south-central Plains...
Ongoing, isolated to widely scattered convection over parts of KS/MO
should weaken/dissipate through the remainder of the morning, but
may leave behind enough cloud material and (especially in MO)
outflow to augment frontal baroclinicity for afternoon convective
initiation. Widely scattered to scattered thunderstorms should
develop on and near the front this afternoon from northern OK and
extreme southern KS to the Ozarks, in a regime of MLCINH
substantially removed by modest low-level convergence and strong diurnal/prefrontal heating. Deep mixing south of the front should
reduce surface dewpoints and buoyancy in the warm sector, but
adequate moisture (with 60s to low 70s F surface dewpoints) should
linger in a narrow post-frontal corridor supporting 2000-3000 J/kg
MLCAPE.

The net result should be high-based, multicell thunderstorms in
mostly weak deep shear, with pulse severe in the form of gusts and
hail. A conditional risk exists for locally significant (65+ kt)
gusts, given the favorably deep subcloud mixed layer with large
DCAPE. However, mesoscale foci for denser coverage of such a threat
still appear too nebulous for a 15% unconditional gust outlook
within the broader marginal area.

..Edwards/Kerr.. 06/29/2024

$$
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ACUS01 KWNS 011252
SWODY1
SPC AC 011250

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 AM CDT Mon Jul 01 2024

Valid 011300Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE NORTHERN/CENTRAL PLAINS...

...SUMMARY...
Severe thunderstorms will be possible today across the northern/
central Plains, especially parts of Nebraska and South Dakota. Areas
of damaging winds and sporadic hail will be possible, along with a
few tornadoes.

...Synopsis...
A strong mid/upper-level anticyclone centered over north TX is
forecast to shift east-southeastward over northern LA and weaken
slightly. This will occur as height falls spread across much of the
Great Plains States ahead of a synoptic-scale trough, initially
located from the northern Rockies across the western Great Basin to
the Sierra Nevada. The trough is expected to progress eastward
through the period, faster on its north end (thus becoming more
positively tilted). By 12Z tomorrow, it should extend from Lake
Winnipeg southwestward across ND, central WY, and UT, to near LAS.

A series of minor shortwaves and vorticity maxima will be embedded
in the foregoing southwest flow aloft, and will traverse the
central/northern Plains today and tonight. That includes small,
convectively generated/enhanced perturbations embedded in a
mid/upper-level monsoonal moisture plume, evident in moisture-
channel imagery from west-central/northwestern MX across AZ, the
Four Corners region, and most of CO/NE. Farther east, a mid/upper
trough -- initially from the lower St. Lawrence River region of
southeastern Canada across Update NY/PA/WV -- will move eastward off
the Mid-Atlantic and New England Coasts between 00-06Z.

The surface map at 11Z showed a cold front -- associated with and
preceding the leading mid/upper trough -- across northeastern/south-
central BC, northern parts of SC/GA/AL/MS, across central AR. The
front is forecast to move offshore from all the Atlantic Coast north
of about SAV by 00Z, then extend from there through a wave over
central GA to near a line from MOB-BTR-GGG, becoming ill-defined
farther northwest. Another cold front was drawn from a triple-point
low over southwestern ND southwestward across central WY and
northern UT. By 00Z, the latter front should reach the central
Dakotas, northwestern NE and northwestern CO. A broad area of low
pressure should slow/stall the front temporarily over northeastern
CO and south-central/southwestern NE tonight, while it advances to
the eastern Dakotas and southeastern UT.

...Central/northern Plains...
Scattered thunderstorms may develop this afternoon over a broad area
of the western Dakotas, and the central High Plains, along/ahead of
the cold front and near a lee trough/weak dryline over parts of
southwestern NE and eastern CO. A few strong-severe thunderstorms
also may form in the post-frontal upslope-flow regime near the
Bighorns and offer severe hail/gusts eastward toward the western
Black Hills.

The most favorable environment for severe will be across parts of southern/central NE near a prominent moist axis, zone of warm
frontogenesis, and also possibly differential heating (from the
southern rim of morning clouds/precip). In this regime, backed flow
and relatively maximized moisture will maximize both kinematic and thermodynamic parameters favorable for supercells. A corridor of
60s to low 70s F surface dewpoints -- already apparent from eastern
OK across western KS to western NE -- should shift northeastward
through the day, eroded on the west side by heating/mixing (as per
modifying the 12Z DDC RAOB) but reinforced father east through moist
advection. That moisture, and strong diurnal heating, will support
a narrow plume of MLCAPE around 2000-3000 J/kg. Locally large
hodographs are expected in the backed surface winds, yielding
effective SRH in the 250-450 J/kg range. Supercells with all severe
hazards (including a few tornadoes and large hail) will be possible
in that regime, especially with relatively discrete storms.
Significant (2+ inch diameter) hail cannot be ruled out, but that
threat may be mitigated somewhat by relatively warm temperatures
aloft in the monsoonal moist plume.

Upscale growth of early convection into lines an clusters is
possible, both in the southern NE regime wherever activity becomes outflow-dominant before encountering the moisture plume, and farther
north as a possible frontal/prefrontal QLCS. The most sustained
potential for upscale evolution appears to be with the central/
southern NE activity shifting tonight into eastern NE, western IA
and the Siouxland region, where inflow-layer moisture and
instability should be greatest. As such, the potential for
cold-pool-aided convective-gust enhancement remains represented by a significant-wind area inside the broader 15% unconditional wind
line. If confidence increases in a specific MCS corridor, that
probability may need to be raised in a succeeding outlook.

...Southeast...
Widely scattered to scattered, multicellular thunderstorms are
expected this afternoon between the frontal zone over GA/SC/AL on
the north, and on the south, sea-breeze and differential-heating
boundaries. The most intense cells will be capable of water-loaded
downbursts near severe limits. A very moisture-rich boundary layer
will persist across the region, with surface dewpoints commonly in
the low/mid 70s F and PW near 2 inches. Strong surface heating will
offset modest mid/upper-level lapse rates enough to yield MLCAPE in
the 2000-3000 J/kg. Low/middle-level flow and shear should be weak,
though a belt of strong northerly to northeasterly winds in upper
levels (near anvil level) may aid in storm organization. Severe
potential should be isolated and pulse in nature, with short-lived,
localized clustering possible, and should wane after sunset.

..Edwards/Kerr.. 07/01/2024

$$
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ACUS01 KWNS 011632
SWODY1
SPC AC 011630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Mon Jul 01 2024

Valid 011630Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN/CENTRAL PLAINS...

...SUMMARY...
Severe thunderstorms should occur this afternoon and tonight across
parts of the northern/central Plains, especially portions of
Nebraska and the Dakotas. Scattered severe/damaging winds, large
hail, and a few tornadoes all appear possible.

...Northern/Central Plains...
A notable upper trough across the northern Rockies will advance
eastward today over the northern/central Plains. Related low-level
mass response will encourage multiple surface lows to slowly deepen
across the northern/central High Plains. An occluded/cold front will
move eastward across the western/central Dakotas through this
evening, while a warm front attempts to lift northward across
northern KS into NE. Current expectations are for robust convection
to develop along both the front in the western Dakotas, and the
higher terrain of WY/CO as large-scale ascent associated with the
upper trough overspreads the warm sector. Low-level moisture will
remain more limited with northward extent into the Dakotas. But,
sufficient instability in a narrow corridor, along with strong
deep-layer shear, is still anticipated. Initial supercells over
western ND/SD should pose a threat for large hail, before convection
quickly grows upscale into a bowing cluster towards central ND/SD
with a greater threat for severe/damaging winds. With sufficient
ambient near-surface vorticity along the front, a brief tornado or
two also appears possible with initially more cellular development.
This activity should weaken with eastward extent tonight as it
encounters much weaker instability towards the MN border.

Initially high-based convection over central CO may pose an isolated
threat for severe wind gusts as it moves into eastern CO/western KS
and encounters a very well mixed boundary layer. The Marginal Risk
has been expanded westward and southward a bit in CO to account for
this potential. Otherwise, thunderstorms should eventually develop
and strengthen by late this afternoon along/east of a surface low
centered over northeast CO. Deep-layer shear will be strong enough
to support supercells, but convective mode may quickly become messy
as activity moves eastward along/near the northward-advancing warm
front in NE. Large hail may occur with any sustained supercell, and
sufficient low-level shear will be present along/near the warm front
to support a threat for a few tornadoes. Even so, a more
clustery/linear mode may become dominant fairly soon after initial
development. This would support a greater threat for severe/damaging
winds, and perhaps isolated gusts up to about 75 mph. Regardless of
continued uncertainty over what the dominant convective mode will
be, the severe threat will likely persist into eastern NE/western IA
this evening and tonight before thunderstorms eventually weaken.

...Southeast...
Scattered to numerous thunderstorms should develop this afternoon
along and south of a cold front draped east to west across parts of
the Southeast. Although mid-level flow and related deep-layer shear
will remain modest, steepened low-level lapse rates though daytime
heating and plentiful low-level moisture will easily support
moderate to strong instability. Occasional strong to damaging winds
may occur with the more robust cores and loosely organized clusters
as they move generally southward through the early evening before
eventually weakening.

..Gleason/Thornton.. 07/01/2024

$$
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ACUS01 KWNS 030552
SWODY1
SPC AC 030550

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1250 AM CDT Wed Jul 03 2024

Valid 031200Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE NORTHERN/CENTRAL HIGH PLAINS AND THE OZARKS TO LOWER OH VALLEY...

...SUMMARY...
Scattered severe thunderstorms are possible across parts of the
northern to central High Plains and from the Ozarks to Lower Ohio
Valley, mainly from late afternoon to mid-evening. The most
favorable corridor for isolated very large hail and significant
severe wind gusts is centered on the central High Plains.

...Synopsis...
A shortwave trough over the southern Canadian Rockies will dig
southeast across the northern Rockies before reaching the
north-central High Plains by early Thursday. As this occurs, a lee
surface trough will sharpen over the High Plains. A convectively
modified cold front will shift east-southeast into the Lower Great
Lakes to the Ozarks. This front will remain quasi-stationary into
the southern TX Panhandle, with the most prominent temperature
gradient from here through northern OK owing to pronounced
differential heating across OK to KS.

...Central to northern High Plains...
To the north of the southern Great Plains baroclinic zone,
predominantly southeasterly low-level flow will attempt to advect
richer moisture from southern/eastern KS. However, most 00Z models
suggest increasing widespread convection from the TX/OK Panhandle
into KS this morning amid low-level warm theta-e advection. This
overturning will likely slow the northwestward moisture return. In
addition, pervasive cloudiness will limit boundary-layer
destabilization over the lower plains. These factors yield a
probable confined plume of appreciable buoyancy and uncertainty over
the amplitude of the peak buoyancy over the central High Plains.

Scattered thunderstorms will likely develop along the lee trough
towards late afternoon, seemingly most probable from northeast CO to
south of the Black Hills. An additional area/round of storms should
also form farther northwest into northeast WY, ahead of the
mid-level DCVA attendant to the approaching shortwave trough.
Relatively modest low-level flow in conjunction with moderate to
strong speed shear above 700 mb will yield moderate hodograph
elongation. This should support widely spaced supercells capable of
large to very large hail, and perhaps a couple tornadoes. Broken
upscale growth with amalgamating convective outflows will probably
occur during the early to mid-evening, which should yield a threat
for isolated wind gusts of 70-80 mph. With potential for convection
to spread relatively quickly into a cooler downstream boundary
layer, confidence is too low to warrant a level 3-ENH threat this
cycle.

...Ozarks to the Lower OH Valley...
Scattered thunderstorms will be possible along the weaker portion of
the frontal zone during the latter half of the afternoon, aided in
part by remnant MCVs from ongoing/forecast convection this morning.
Along the fringe of modest mid-level southwesterlies, roughly
parallel to the weak front, multicell clustering is anticipated. A
threat for strong to localized severe gusts may be sufficient for
potentially scattered wind damage.

..Grams/Squitieri.. 07/03/2024

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ACUS01 KWNS 041253
SWODY1
SPC AC 041252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Thu Jul 04 2024

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MISSISSIPPI VALLEY...AND LOWER OHIO VALLEY TO SOUTHERN
PLAINS...

...SUMMARY...
Severe thunderstorms will be possible across parts of the upper
Mississippi Valley, and lower Ohio Valley to southern Plains.

...Synopsis...
In mid/upper levels, strengthening ridging over the Pacific Coast
will result in height rises over much of the Northwest, while the
subtropical ridge weakens slightly across the Gulf Coast States and
GA. Broadly cyclonic flow still will prevail from the northern
Rockies across the central/northern Plains and Great Lakes. Within
that flow, a well-developed shortwave trough is evident in moisture-
channel imagery from the Dakotas to northeastern CO, preceded
closely by a smaller but convectively augmented perturbation over
parts of IA, northwestern MO and eastern KS. As these features
pivot through the broader cyclonic flow today, the leading
perturbation's MCV should move across northern parts of IL/IN/OH and
perhaps extreme southern Lower MI. The trailing, stronger trough
should extend from central MN to central NE by 00Z, then cross the
remainder of MN/NE and much of IA overnight with an at least
intermittently closed 500-mb low.

At the surface, the 11Z analysis showed a frontal-wave low over
southwestern IA, with some possible augmentation from wake effects
related to an area od precip/convection to the east and southeast.
A wavy cold front, with several weak lows attached, was drawn from
there across eastern/southern KS, the TX Panhandle, and north-
central NM, preceded by outflow boundaries from northern OK across
southern MO. By 00Z, the cold front should reach northwestern IL,
central MO, southwestern OK, and central NM, with diffuse warm front
over central parts of IL/IN/OH near or north of a convective
boundary. By 12Z, the cold front should reach northwestern IN,
southern IL, southern MO, southeastern OK, north-central/northwest
TX, and southern NM.

...Southern Plains to lower Ohio Valley...
Multiple rounds of convection are expected across this corridor
today, contributing to the overall severe potential, without sharp
demarcation between the three main regimes numbered below. The
outlook has been expanded northeastward up the Ohio Valley in
deference to an increased severe threat related both directly and
indirectly to MCV-aided convection.

1. Ahead of the MCV and accompanying perturbation, a broad area of
clouds and precip is apparent from central/northern MO across
southern/central IL and extending into southern IN. The southern
rim of this precip area contains scattered, initially non-severe
thunderstorms, utilizing a broad warm-advection/moisture-transport
plume with parcels isentropically lifted to an LFC. All this
activity will continue to shift eastward through the remainder of
the morning, helping to reinforce the ambient baroclinic zone across
the area, which in turn should help to focus later/afternoon
development. Meanwhile, some of the morning activity may encounter
a diurnally destabilizing boundary layer with weakening MLCINH, more
purely surface-based effective-inflow parcels, and rich boundary-
layer moisture. The associated outflow/differential-heating
boundary may shift somewhat northward today over southern/central
parts of IL/IN before the leading perturbation passes, and also, can
act to back low-level flow and enlarge hodographs, in a moisture-
rich, low-LCL environment. As such, some supercell/tornado
potential has become evident, with damaging gusts and isolated large
hail also possible.

2. Closely following that regime, and perhaps blending with the
western part of it, a round of widely scattered to scattered
thunderstorms is expected along/ahead of the front from central/
southern MO to the lower Ohio Valley this afternoon into evening, as large-scale ascent from the stronger/trailing shortwave trough
overspreads a still very moist air mass. Strong insolation and
surface dewpoints in the low/mid 70s F will offset modest mid/upper-
level lapse rates to yield MLCAPE in the 1500-2500 J/kg range south
of the front and outflow boundary. While warm-sector surface flow
will be weak, and more veered than on the boundary, sufficient
deep/speed shear still should be present for a blend of multicells
and at least transient supercells, with some clustering/bowing of
convection possible as well. Damaging to severe gusts will be the
main threats with this activity, though a tornado and isolated large
hail may occur.

3. Vertical shear generally will weaken with westward extent near
and ahead of the front, but substantially hotter surface conditions
will contribute to very steep boundary-layer lapse rates and
"inverted-v" thermodynamic profiles in the subcloud layer. A plume
of 2000-2500 J/kg MLCAPE is expected over northern OK, decreasing
southwestward across northwest TX into drier and still more deeply
well-mixed conditions. As such, severe downdrafts and isolated
large hail will be possible, with greatest potential concentration
of the gust threat in the OK to southeast KS corridor. Activity
forming in this regime also may persist and move/merge into the MO
environment from late afternoon into evening.

...Upper Mississippi Valley region...
Scattered thunderstorms are expected to develop as early as midday,
and continue through the afternoon, east through southeast of the
developing mid/upper low and primary vorticity maximum. Some of
this convection will become supercells, capable of large hail and
damaging gusts, with clustering or line segments also possible.

The most favorable low-level parameter space for that convection to
become severe still appears to be across southern MN, northern IA
and western WI, where residual moisture north of the optimal warm
sector still will support surface dewpoints in the mid 60s F, amid
pockets of favorable diurnal heating and low-level warm advection
behind the morning cloud/precip plume. Large-scale ascent will
occur in relation to midlevel DCVA preceding the trough aloft, and
the left-exit region of a cyclonically curved, 250-300-mb speed max.
Though low-level flow should be modest, favorable deep shear
(effective-shear magnitudes in the 45-55-kt range) will support
organized convection for several hours. Overall, this activity
should diminish through the evening as nocturnal cooling and
expansive outflow air collectively stabilize the boundary layer.

..Edwards/Kerr.. 07/04/2024

$$
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ACUS01 KWNS 051254
SWODY1
SPC AC 051252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Fri Jul 05 2024

Valid 051300Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE UPPER OHIO VALLEY INTO THE CENTRAL AND SOUTHERN APPALACHIANS...

...SUMMARY...
Scattered severe thunderstorms will be possible midday into the
afternoon across parts of the upper Ohio Valley into the central and
southern Appalachians. Damaging gusts 50-65 mph will be the primary
severe hazard.

...Synopsis...
Water-vapor imagery this morning shows a mid-level shortwave trough
and associated low moving east across the mid to upper MS Valley and
into the western Great Lakes. A belt of strong southwesterly 500-mb
flow (50-60 kt) will move through the base of the trough from the
lower MO Valley east-northeastward through IN/OH and into the Lower
Great Lakes through early evening. Upstream of this disturbance, a
lower amplitude shortwave trough will move southeastward from AB
into MT during the day.

...Eastern Great Lakes/Ohio Valley/Southern and Central
Appalachians...
A convectively augmented lead disturbance over the lower OH Valley
will continue to progress eastward today ahead of a larger-scale
trough forecast to pivot east across the OH Valley. An ongoing
squall line from southern IN to the AL/TN border, will move east
into a very moist and destabilizing airmass. Surface analysis shows
a reservoir of lower to mid 70s deg F dewpoints from north-central
AL north-northeastward through the central Appalachians and OH River
vicinity. A belt of stronger mid-level southwesterly flow will
likely remain north of the OH River, but some enhancement to 2-6 km
flow (reference Memphis, Paducah, Fort Campbell, and Evansville
WSR-88D VADs) will likely spread downstream across TN/KY and into
southern OH and WV. Visible-satellite imagery denotes strong
heating will occur ahead of the MCS, thereby contributing to upwards
of 1500-3000 J/kg MLCAPE by early afternoon (2400 J/kg MLCAPE per
Nashville 12 UTC raob). Organized multicells (via the MCS) will be
capable of scattered 50-65 mph gusts and wind damage. Farther south
into the southern Appalachians and Carolinas/VA Piedmont, weaker
flow but very moist/unstable conditions later today will support
scattered thunderstorms and an isolated risk for damaging gusts with
the stronger wet microbursts.

Farther north, more uncertainty and potentially lower strong/severe
storm coverage will extend from Lower MI across the southern/Lower
Great Lakes into PA and west-central New York. A hail threat
may also develop in parts of Lower Michigan, ahead of the
upper-level trough, where mid-level temperatures will be cooler
which will aid in steeper mid-level lapse rates. Localized damaging
gusts will be the main severe risk.

...Eastern New Mexico...
Southwestern periphery of stronger mid-level northwesterly flow will
glance the southern High Plains in between a mid-level anticyclone
centered near the northern CA coast and the larger-scale trough over
the Midwest. Strong heating and moist upslope flow (dewpoints near
60 F) will contribute to initially isolated storms preferentially
developing over the higher terrain by early to mid afternoon. Model
guidance shows MLCAPE peaking in the 1500 to 2000 J/kg range, with
0-6 km shear around 30 kt. Some organization of storms is possible,
mainly via multicells and perhaps transient supercell structures.
Isolated severe gusts/hail may accompany the stronger thunderstorms.

...MT...
Aforementioned mid-level impulse will move into central/eastern MT
this afternoon/evening. Strong heating amidst 40s dewpoints will
yield weak buoyancy (500-1000 J/kg MLCAPE) but steep lapse rates. A
few stronger storms may be capable of locally severe gusts for a few
hours late this afternoon before this activity subsides later this
evening.

..Smith/Bentley.. 07/05/2024

$$
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ACUS01 KWNS 061228
SWODY1
SPC AC 061227

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0727 AM CDT Sat Jul 06 2024

Valid 061300Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
CENTRAL GREAT PLAINS...

...SUMMARY...
Scattered severe thunderstorms are possible over portions of the
central Great Plains this afternoon into this evening. Large to
very large hail and severe gusts are the primary hazards.

...Great Plains/Upper Midwest...
A mid-level disturbance, embedded within a belt of cyclonic
mid-level flow centered over the Upper Midwest, will move
southeastward from the western Dakotas/WY into eastern SD/NE today.
At the surface, a weak area of low pressure will migrate slowly
eastward from northeast CO into NE as a cold front pushes southeast
across the central High Plains. By afternoon, several pockets of
moderate instability will likely be in place from western Kansas
northeastward into central and eastern Nebraska. Convection is
first expected to develop to the north of the surface low in
north-central Nebraska, with cell coverage gradually expanding
southwestward into western Kansas. Several clusters of storms are
expected to persist into the early to mid evening along the
instability corridor from west-central Kansas into central eastern
Nebraska.

Relatively steep 700-500 mb lapse rates from 7 to 8 C/km and a wind
profile supporting storm organization, will potentially favor a
couple of supercells capable of large to very large hail.
Relatively quick upscale growth into one or two linear clusters is
expected towards early evening. Severe gusts will likely become
more prevalent during this evolution towards more outflow-dominant
storms.

Further west, isolated thunderstorms will also be possible behind
the front from the central High Plains northeastward into southern
South Dakota. In this area, lower surface dewpoints and weaker
instability should keep any severe threat marginal. A marginal
severe threat is also expected to develop southward across parts of
the southern High Plains. If confidence can increase on the development/placement of a linear cluster across northwest TX by
early this evening, a focused area of perhaps locally greater threat
for severe gusts may occur over parts of the South Plains/Caprock
vicinity in TX. Nonetheless, weaker large-scale ascent in the
southern High Plains should limit overall storm coverage/intensity.

...Northeast...
The 06/00z MPAS-HT-NSSL model run seemed to reasonably depict storm
development earlier this morning over southeast NY moving into CT.
In wake of this activity as it moves northeast and dissipates later
this morning, isolated to widely scattered thunderstorms are
forecast to develop from the lower Hudson Valley into upstate NY and
farther northeast into southern ME. A mid-level vorticity lobe over southwestern ON and near Lake Erie this morning, will move northeast
into the St. Lawrence Valley later today. Ample deep-layer shear
and moderate buoyancy will support organized cells despite weak
large-scale forcing for ascent. Localized 50-60 mph gusts capable
of wind damage are possible with the stronger storms this afternoon
into the early evening.

..Smith/Bentley.. 07/06/2024

$$
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ACUS01 KWNS 071253
SWODY1
SPC AC 071251

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Sun Jul 07 2024

Valid 071300Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN GREAT PLAINS...AND FROM THE MIDDLE TEXAS COAST INTO FAR
SOUTHWEST LOUISIANA...

...SUMMARY...
A few tornadoes will be possible along the middle to upper Texas
Coast into southwest Louisiana as Tropical Cyclone Beryl approaches
the coast and makes landfall later tonight. Scattered severe
thunderstorms are possible across parts of Oklahoma into northern
and northwestern portions of Texas.

...Central and Southern Plains...
An extensive cluster of showers and thunderstorms early this morning
and related stabilizing effects have pushed southward into central
OK. Outflow associated with this early day convection will likely
serve as a focus for additional storm development later today.
Water-vapor imagery shows broad, cyclonic mid-level flow with a
trough moving southeast from the Dakotas/northern High Plains. This
mid-level trough will move into the central High Plains late in the
period as the northern part of the trough shifts east into the Upper
Midwest. Along the periphery of the residual outflow, appreciable destabilization is expected with mid 60s to lower 70s surface
dewpoints contributing to moderate to strong instability over the
southern Great Plains. At the surface, a cold front will advance
southward across the central Plains. Scattered to numerous
thunderstorms are forecast to develop during the afternoon into the
evening. Severe gusts and large hail will be the primary hazards
with the stronger storms as this activity likely grows upscale into
one or two linear clusters this evening.

...Middle to Upper Texas Coast...
Tropical Cyclone Beryl and its outer envelope of strong low-level
flow, will continue to approach the TX coast through much of the
period before making landfall tonight. The outer convective bands
within the northern and northeast portions of the larger system will
overspread the TX coast beginning by late morning and eventually
into southwest LA. Coincident with the strengthening lower
tropospheric flow, low-level shear (i.e., enlarging hodographs) will
increase across the middle to upper Texas Coast into southwest LA.
Embedded supercells within the convective bands and transient
rotating updrafts will pose an isolated risk for tornadoes perhaps
beginning as early as this afternoon. This tornado risk will likely
increase into the evening and tonight as Beryl moves over the shelf
waters and approaches the coast tonight.

...IA into northern WI...
An ill-defined surface pattern will feature a weak front/surface
trough moving east from the eastern Dakotas and the NE Sandhills
into the IA/MN vicinity later today. East of this wind shift, a
relatively moist airmass will destabilize in proximity to a
positively tilted mid-level trough over the Upper Midwest into the
central High Plains. A belt of moderate mid-level flow will move
through the base of the trough over portions of NE eastward into IA.
With no expected appreciable moisture advection through peak
heating, surface dewpoints will likely remain in the upper 50s to
lower 60s north, to the lower to mid 60s south. Model forecast
soundings show generally moderate buoyancy (1000-2500 J/kg MLCAPE).
Despite the diurnal destabilization, the modest large-scale forcing
for ascent will likely limit storm coverage/intensity. A localized
risk for a strong storm or two may materialize, but uncertainty
remains high precluding the introduction of low-severe probabilities
this outlook update.

..Smith/Bentley.. 07/07/2024

$$
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ACUS01 KWNS 072000
SWODY1
SPC AC 071958

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Sun Jul 07 2024

Valid 072000Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDDLE/UPPER TEXAS COAST/FAR SOUTHWEST LOUISIANA...SOUTHERN
PLAINS...AND EASTERN COLORADO/FAR NORTHEAST NEW MEXICO...

...SUMMARY...
A few tornadoes will be possible along the middle to upper Texas
Coast into southwest Louisiana as Tropical Cyclone Beryl approaches
the coast and makes landfall later tonight. Scattered severe
thunderstorms are also expected across eastern Colorado, northeast
New Mexico, and parts of the southern Plains.

...20Z Update...
The Marginal and Slight Risks have been expanded southwestward
across western portions of the TX South Plains, where cumulus is
increasing this afternoon, and somewhat favorable instability and
deep-layer shear are already in place. Uncertainty remains rather
high regarding the potential for redevelopment across parts of
Oklahoma later this afternoon into the evening, in the wake of
substantial antecedent convection and outflow. However, relatively
strong heating is underway across parts of southwest/south-central
OK, and a few strong to severe storms remain possible by early
evening. No changes have been made to the Oklahoma portion of the
Slight Risk.

No changes have been made to the other Slight Risks. Scattered
strong to severe storms are still expected from the CO Front Range
into eastern CO/northeast NM. Also, for parts of the middle/upper TX
Coast into far southwest LA, the tornado threat is expected to
increase late tonight into early Monday morning, as Tropical Cyclone
Beryl approaches the coast. See the previous discussion below for
more details regarding these areas.

..Dean.. 07/07/2024

.PREV DISCUSSION... /ISSUED 1155 AM CDT Sun Jul 07 2024/

...Middle to Upper Texas Coast...
Tropical Cyclone Beryl and its outer envelope of strong low-level
flow, will continue to approach the Texas coast through much of the
period before making landfall tonight. Reference NHC for the latest
forecast details. Coincident with the expected strengthening of
lower tropospheric flow, low-level shear (i.e., enlarging
hodographs) will increase across the middle to upper Texas Coast
into southwest Louisiana through tonight, with embedded supercells
within the convective bands and transient rotating updrafts
potentially posing an isolated risk for tornadoes, especially into
tonight.

...Eastern Colorado/Front Range and far northeast New Mexico...
Low stratus persists at midday across east-central/southeast
Colorado toward the Raton Mesa vicinity, but more aggressive
clearing is occurring across northern Colorado. A belt of cyclonic
flow aloft will continue to overspread the region with some cooling
aloft, while low-level moisture and upslope flow both increase
through late today. Storms should develop near the foothills/I-25
later this afternoon and evening, likely with a bit
later-than-typical time frame for strong/severe thunderstorm
development. Moderate instability and strong shear will support
supercells capable of large hail, with some stronger wind gusts also
a possibility. Potentially severe storms may continue especially
across southeast Colorado/northeast New Mexico much of the night.

...Southern Plains including Oklahoma and North Texas/Panhandle...
A semi-organized cluster of storms has evolved across east-central/south-central Oklahoma and may persist eastward early
this afternoon with a localized severe risk. Trailing outflow and a
residual surface cold pool are considerable factors in its wake,
although modification is likely into the afternoon. Storms may
redevelop as this occurs, potentially including parts of the Texas Panhandle/Texas south Plains into western/southern Oklahoma and the
Red River vicinity, with isolated severe storms possible later this
afternoon through early evening.

...Iowa/northern Missouri/western Illinois to northern Wisconsin...
Surface pattern will remain relatively weak and ill-defined, but at
least widely scattered thunderstorms are expected particularly
across northern Missouri into Iowa and western Wisconsin near a weak
surface wave/boundary. Even with some cirrus and some residual early
day showers, moderate destabilization should occur across the
region, with development and intensification of storm clusters this
afternoon in the presence of 20-30 kt effective shear. Isolated
instances of wind damage is the most probable hazard, but some hail
could also occur. Some strong storms could occur as far north as
Wisconsin and perhaps the western Upper Peninsula of Michigan, but
the overall potential for organized severe storms should remain
limited.

...Southern Appalachians...
Short-term guidance substantiates the likelihood of scattered
thunderstorm development this afternoon, with some potential for
storms to cluster by late afternoon across upstate parts of the
Carolinas and far northeast Georgia. Mid-level lapse rates will be
weak with relatively tall/skinny CAPE, but some localized damaging
downbursts may occur.

$$
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ACUS01 KWNS 111257
SWODY1
SPC AC 111255

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 AM CDT Thu Jul 11 2024

Valid 111300Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
SOUTHERN ARIZONA...

...SUMMARY...
Severe thunderstorm gusts are possible over parts of southern
Arizona from midafternoon into early evening.

...Synopsis...
In mid/upper levels, the overall pattern will change little through
the period, with mean ridging in the West, and troughing over the
Great Lakes and vicinity. The persistent anticyclone will remain
over the Great Basin, with some deamplification of ridging to its
north leading to more-zonal flow across the northern tier of states
from WA-ND. A weak shortwave trough -- apparent in moisture-channel
imagery over parts of central/eastern MT -- should move slowly east-southeastward across the northern High Plains today amid
difluent flow. Meanwhile and downstream, a pronounced shortwave
trough now over parts of WI/IL/IA should eject northeastward over
the Upper Great Lakes and weaken, while smaller/upstream
perturbations help to maintain the mean trough. Both the
low/middle-level remains of TC Beryl, and a closely associated
shortwave trough of midlatitude origins, should shear northeastward
across southern QC, the lower St. Lawrence Valley, and northern New
England, weakening considerably.

At the surface, 11Z analysis showed a low near the NH/QC border with slow-moving, weakening cold front across western New England, the
coastal Mid-Atlantic/Carolinas, southern GA, and FL Panhandle,
becoming quasistationary along the northwestern Gulf Coast. This
front should continue weakening near or just east of its present
position through the period, over the Northeast, and also weaken
over the Gulf Coast and southern Atlantic Coast States. Enough
low-level shear exists over parts of ME today to support a
conditional supercell potential, but strength/coverage/longevity are
in question due to weakness of both instability and lift.
Elsewhere, a lee trough analyzed on that chart over eastern parts of
MT/WY/CO should remain over the central/northern High Plains today,
with some eastward drift possible.

...AZ...
Widely scattered to scattered thunderstorms are expected to develop
this afternoon, over the Mogollon Rim and smaller mountain ranges to
the south. That will occur as strong insolation at those higher
elevations preferentially removes MLCINH, in the presence of
generally greater low-level moisture than previous days. Some
strengthening of flow aloft is expected over this region, around the southeastern rim of the anticyclone. This will support convective
motion off the Rim (and small mountain ranges to its south), then
atop well-heated/deeply mixed boundary layers of the desert floor.
Isolated strong-severe gusts are possible from the relatively early, more-discrete activity.

With the lower-elevation boundary layers being very deep (surface to
around 600 mb), but enough moisture maintained through mixing to
keep surface-based buoyancy (MLCAPE in the 500-1000 J/kg range),
expect some aggregation of outflows with additional development atop
those -- especially over southeastern AZ. The net result should be
both translation and developmental propagation of convection
southwestward to and across the international border, with swaths of strong-severe gusts possible.

...Northern High Plains...
Isolated to widely scattered, high-based thunderstorms are expected
to form near the lee trough, where both relatively maximized
convergence and strong surface heating should contribute to enough
lift for convective initiation. The main concern up and down the
corridor should be damaging to severe gusts, given the deeply mixed
subcloud layer and ample downdraft-acceleration opportunity that
will afford. Isolated severe hail also may occur, amidst enough
deep-layer shear for some organized thunderstorms (effective-shear
magnitudes of 30-40 kt). Lack of greater moisture and buoyancy will
be a limiting factor for coverage and intensity of convection, which
should diminish rapidly after dark.

..Edwards/Bentley.. 07/11/2024

$$
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ACUS01 KWNS 121257
SWODY1
SPC AC 121255

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 AM CDT Fri Jul 12 2024

Valid 121300Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS
TO LOWER OHIO VALLEY...AND OVER THE NORTHERN AND CENTRAL GREAT
PLAINS...

...SUMMARY...
Isolated severe wind and hail will be possible this afternoon from
the Ozarks to lower Ohio Valley, and over the northern and central
Great Plains from late afternoon into tonight.

...Synopsis...
Deamplification of the northern-stream pattern is forecast in mid/
upper levels, as a persistent trough over the Great Lakes and
vicinity moves eastward and weakens substantially. A height
weakness will continue to extend from that area southwestward across
the mid Mississippi Valley, Arklatex, and south TX, with several embedded/slow-moving vorticity lobes. Meanwhile, a broad area of
difluent, zonal to northwesterly flow should continue over the
central/northern Plains region, northeast of a prominent anticyclone
shifting slowly eastward across the Great Basin and Four Corners
regions.

At the surface, the 1Z analysis showed weak lows over northeastern
MT and southwestern SD, along a quasistationary to slow-moving warm
front drawn from southern AB to western SD, central/southeastern NE,
central MO, and southern IL. The slightly better-defined MT low
should move slowly eastward to northwestern ND by early evening,
while the frontal zone to its southeast drifts eastward and
northward over central SD, eastern NE, northeastern KS, and central/
northern MO. A lee trough -- initially drawn from western SD to
eastern CO and the TX Panhandle -- should meander erratically near
its present position today, with some adjustment by falling
pressures related to strong surface heating.

...Northern/central Plains...
Isolated to widely scattered thunderstorms are moving southeastward
over portions of southeastern SD to central N this morning, in a
zone of weak DCVA aloft superimposed on a broader area of low-level
warm/moist advection above the surface. While an isolated,
marginally severe hail report cannot be ruled out in another couple
hours, the overall decreasing trend should continue as the LLJ
likewise weakens through the remainder of the morning.

Isolated to scattered, high-based thunderstorms are expected to
develop over western parts of the outlook area near the lee trough
today, within a broad area of strong diurnal heating. Isolated
development also may occur farther east near the warm front and
greater low-level moisture, though weaker lift and stronger MLCINH
are expected in that corridor than near the lee trough. Activity
west of the front will move atop a deeply well-mixed boundary layer
suitable for strong-severe downdrafts. Surface dewpoints mixing
well down into the 40s to mid 50s will result in decreasing MLCAPE
as MLCINH also weakens, with around 500-1000 J/kg expected in the
most-probable area for storm formation. Buoyancy will increase
eastward as mixing weakens, but capping strengthens, with a corridor
of 60s F dewpoints and 2000-3000 J/kg MLCAPE along and just east of
the front. Considerable uncertainty exists how much of the lee-
trough activity can aggregate cold pools and potentially utilize
forced ascent eastward into the greater moisture, for longer and
better organization.

Outside the lee trough, forcing for convective-scale lift appears
nebulous and poorly focused across the region, with considerable
uncertainty remaining on preferred potential corridor(s) for greater
severe concentration. One possibility is closer to a northern-
stream mid/upper trough north of the international border, but still
with uncertainty on the southern extent into the CONUS of any
resulting MCS. These uncertainties are reflected in a wide range of
convective distributions and intensities across the various
convection-allowing guidance, as well as implied from precip fields
in the deterministic synoptic models and their ensembles. As such,
a broad marginal area is maintained for this outlook cycle, with
embedded upgrade(s) possible if mesoscale trends and 12Z/later
guidance come into clearer focus.

...Ozarks to lower Ohio Valley...
Isolated to widely scattered, non-severe thunderstorms are ongoing
over parts of southern MO, northwestern AR and extreme eastern OK,
in a field of low-level WAA and weak DCVA. A related increase in
convective coverage and intensity is possible farther east and
southeast across portions of this region as the foregoing boundary
layer diurnally destabilizes, with marginally severe gusts or hail
possible in the strongest cells.

One of the vorticity lobes embedded in the height weakness aloft,
over eastern KS to central/eastern MO, is being enhanced by an MCV
from prior/overnight convection now over southwestern MO. This
feature will move slowly eastward today and may contribute to
relatively maximized thunderstorm coverage in an increasingly
unstable airmass from the Ozarks to lower Ohio Valley this
afternoon. Rich low-level moisture (surface dewpoints commonly
upper 60s to low 70s F) and diurnal heating should offset modest mid/upper-level lapse rates to yield peak MLCAPE in the 2000-3000
J/kg range. Weak low/middle-level flow and modest shear should
limit organization enough that severe potential should remain
isolated and poorly organized.

..Edwards/Broyles.. 07/12/2024

$$
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ACUS01 KWNS 131259
SWODY1
SPC AC 131257

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 AM CDT Sat Jul 13 2024

Valid 131300Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY...

...SUMMARY...
Multiple clusters of strong to severe thunderstorms are possible
across portions of the Northern Plains into the Upper Mississippi
Valley today and tonight.

...Synopsis...
The basic middle/upper-level pattern will change little over the
CONUS this period, and will feature:
1. A strong anticyclone centered over the Four Corners region, and
covering most of the landmass from the Sierra Nevada to the
south-central High Plains, and MX border to southern parts of ID/WY.

2. Extensive but fairly weak synoptic troughing from the Great
Lakes to the mid Mississippi Valley, TX and north-central MX.
3. A belt of west-northwest to northwest flow across the northern
Rockies, northern Plains and upper Mississippi Valley, becoming
weaker and strongly difluent over the Upper Great Lakes and lower
Missouri Valley.

A northern-stream shortwave trough -- evident in moisture-channel
imagery over southern AB -- should move across southern SK today and
reach northern MN and adjoining parts of ON overnight. Downstream,
MCVs and accompanying small, convectively generated/enhanced
shortwave perturbations are apparent over the ND/MB border, west-central/southwestern MN, and the NE Sandhills. The MN feature
may be most influential for severe potential, and is expected to
move southeastward over southern WI through this evening.

At the surface, 11Z analysis showed a low over southern MB near
Winnipeg, with cold front southwestward over central/southwestern ND
and southeastern MT. A wavy, warm to quasistationary front was
drawn from the low southeastward across central/southeastern MN to
central IL. The latter boundary should move little through the
period, except where shifted/reinforced on the mesoscale by
convective processes, such as currently across parts of southern MN.
The cold front should move to northwestern MN and northern SD by
00Z, decelerating or perhaps stalling over
southeastern/south/central MT.

...North-central CONUS...
A multi-episode, somewhat conditional, but potentially significant
severe threat exists across the north-central CONUS through tomorrow
morning. Although individual severe thunderstorms and a few
clusters/complexes are possible across the broader swath from MT to
the Upper Great Lakes, two corridors of greatest convective/severe
potential are apparent, with some spatial overlap in the middle,
represented for now by the 15% "slight risk" probabilities. If/as
confidence increases in especially wind potential with either of
these, based on succeeding guidance and mesoscale environmental
trends, more tightly focused/greater probabilities may need to be
introduced.

1. Eastern Dakotas to Lake Michigan vicinity:
An ongoing, arc of convection and precip, with scattered embedded thunderstorms, is moving southeastward across southern MN. This
complex earlier was responsible for generating the aforementioned
MCV. That feature may aid in additional development and maintenance
of thunderstorms later this morning, along either the leading-edge,
low-level pressure theta-e perturbation of the earlier complex, or
the trailing outflow/differential-heating boundary. The main
concern will be severe gusts -- perhaps in an organized swath --
with isolated large hail possible. Until then, isolated severe
hail/gusts may occur with the more isolated strong-severe convection
in the ongoing complex.

Additional activity may form along or north of the resulting
boundary almost anytime this afternoon or evening, lending timing
uncertainty to the onset of any convection that may grow upscale
into an MCS with primary wind concern. However, the process appears
probable enough at some point that the corridor of severe
probabilities should be maintained for now. Rich low-level moisture
will persist south of the front/outflow in this corridor, with upper
60s to mid 70s F surface dewpoints common. Combined with diurnal
heating, this should contribute to afternoon MLCAPE ranging from
around 3000-4000 J/kg over the eastern Dakotas, southwestern MN and northwestern IA south of the baroclinic zone (where lapse rates will
be greatest) to around 2000-2500 J/kg in southern WI. Although
low-level flow and hodographs generally will be weak, boundary-aided enhancements to low-level vorticity and shear may contribute some
tornado risk.

2. Northern High Plains to eastern Dakotas:
Widely scattered to scattered thunderstorms are expected to develop
close to the MT/SK border, on either or both sides, late this
afternoon into evening. This activity should move southeastward
into a substantial post-frontal easterly flow component near the
surface, aiding both storm-relative winds in the inflow layer and
low-level shear. In the regime of enhanced mid/upper gradient flow
between the border shortwave to the east and the Four Corners
anticyclone, and with near neutral large-scale forcing, deep shear
should be favorable as well, despite weak absolute speeds in the
boundary layer.

As such, high-based supercell and multicell activity is possible
early amidst 35-45-kt effective-shear magnitudes, and atop a still
well-mixed boundary layer remaining from diurnal heating. Large
hail and localized severe/downburst gusts will be possible while
activity still is relatively discrete. Any upscale aggregation of
outflow and related forced ascent would move into a progressively
moister environment with continued steep lapse rates above the
surface -- all supporting 1500-2500 J/kg MLCAPE and enough remaining
well-mixed low-level air and related DCAPE to sustain an organized,
potentially significant wind threat with any forward-propagating
complex(es) into tonight.

..Edwards/Broyles.. 07/13/2024

$$
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ACUS01 KWNS 140535
SWODY1
SPC AC 140534

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 AM CDT Sun Jul 14 2024

Valid 141200Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN PLAINS INTO THE UPPER MIDWEST...

...SUMMARY...
Strong to severe thunderstorms are expected from the northern Plains
into the Upper Midwest.

...Northern Plains to Upper Midwest...

Large-scale pattern is not expected to change appreciably during the
day1 period, though some amplification is possible later in the
week. Upper high is forecast to remain anchored in the Four Corners
vicinity while seasonally strong mid-level flow will hold along a
corridor near the US/Canadian border. Negligible height changes are
expected during the first half of the period, though a few notable
short waves will track east-southeast from southern AB/SK into the
Great Lakes. Each short-wave trough should encourage convective
development -- some of it will likely be severe.

Early this morning, a weak MCS was propagating southeast across
northern IL/southern Lake MI. This activity is supported by a weak
disturbance and should progress into the southern Great Lakes/OH
Valley later today. Diurnal heating will contribute to strong
buoyancy, and robust updrafts may evolve along the leading debris
field by mid day. Locally severe winds may develop if convection
reintensifies.

Of more concern will be convection that develops across the northern
Plains later in the afternoon. A strong short-wave trough will dig
southeast across southern AB by 15/00z before translating into
MB/eastern Dakotas by the end of the period. It appears a weak
surface low should evolve ahead of this feature over eastern MT
early, then shift into central SD by peak heating. A
northwest-southeast corridor of low-level warm advection will extend
across the Dakotas north of a synoptic boundary that will be draped
from southern MN-central SD-northeast MT. Strong boundary-layer
heating will negate CINH across the High Plains such that isolated
convection should develop by 22z. This activity will mature and grow
upscale through the evening. Early storm mode should be
supercellular, then clustering will lead to an MCS that is expected
to track southeast toward the mid MO Valley. Very steep lapse rates
will lead to strong buoyancy, and potentially very large hail
(possibly in excess of 2 inches). Very strong winds (>70mph) may
also be noted along the leading edge of the surging MCS.

..Darrow/Moore.. 07/14/2024

$$
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ACUS01 KWNS 160548
SWODY1
SPC AC 160547

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1247 AM CDT Tue Jul 16 2024

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE OHIO VALLEY AND NORTHEAST AND OVER THE CENTRAL PLAINS...

...SUMMARY...
Strong to severe thunderstorms are possible from the central Plains
across the Mid Mississippi and Ohio Valleys into the Northeast later
today. Greater severe-thunderstorm potential is anticipated across
the central Plains vicinity, and from the Upper Ohio Valley into the
Northeast.

...Upper Ohio Valley to the Northeast...

Latest model guidance continues to suggest a seasonally strong upper
trough will dig southeast across MB/ON into the Great Lakes later
today. This evolution will force southern extent of stronger
mid-high-level flow to sag south across the mid MS and OH Valley
region, as well as New England. Of particular note early this
morning, a well-defined MCS has evolved over the Midwest with the
leading edge of this complex arcing from southern lower MI-central
IN-central IL. Remnants of this MCS are expected to serve as the
focus for renewed robust thunderstorm development early this
afternoon. Current speed/movement suggests strong/severe
thunderstorm development will occur over the upper OH Valley as
temperatures warm into the mid 80s. MCV is currently located over
southern Lake MI and this feature will track across extreme southern
ON which should encourage upscale convective growth during the
afternoon. Damaging winds are the primary concern with this
convection.

Somewhat removed from this feature, very warm surface temperatures
are expected across northern VA, the Delmarva into NJ. Latest
guidance suggests convective temperatures in the upper 90s will be
breached by 22z. PW values are fairly high despite the warm
temperatures, and severe downbursts could be noted with storms that
evolve along this corridor.

...Central Plains...

Northwesterly mid-level flow is forecast to strengthen a bit across
the central High Plains as the Great Lakes trough becomes a dominant
feature in the eastern US. Latest model guidance suggests a surface
front will settle across southern KS, arcing into southeast CO by
late afternoon. Strong boundary-layer heating along/south of this
boundary will allow temperatures to soar above 100F and any CINH
will easily be removed. High-based convection that evolves near this
boundary may efficiently generate strong downdrafts.

Upslope flow across eastern CO favors convection generating off the
higher terrain which should congeal downstream over the Plains
during the evening. This activity would then propagate southeast
toward northwest OK during the overnight hours.

Models also continue to generate robust convection ahead of a weak
short-wave trough digging toward NE by late afternoon. A weak
surface low is forecast to develop in response to the digging short
wave, and a small corridor of focused low-level convergence is
expected to aid this development.

...Southern MO to southern IN...

Considerable uncertainty exists regarding convective evolution
today. While there is confidence in scattered convection developing
along a pronounced frontal zone at some point, most model guidance
is notably inconsistent due to varying influences from early-day
thunderstorms and their effect on air mass destabilization. Some
consideration was given to increasing severe probabilities along
this corridor, but confidence in placement/timing of strongest
convection does not warrant this at this time.

..Darrow/Marsh.. 07/16/2024

$$
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ACUS01 KWNS 171252
SWODY1
SPC AC 171251

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0751 AM CDT Wed Jul 17 2024

Valid 171300Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE MID-ATLANTIC INTO CENTRAL/SOUTHERN NEW ENGLAND...

...SUMMARY...
Damaging thunderstorm gusts appear most likely and concentrated
today over parts of the Mid-Atlantic into central/southern New
England.

...Synopsis...
In mid/upper levels, a seasonally high-amplitude pattern will
dominate the CONUS through the period, with longwave ridging in the
West and troughing in the East. Anchoring the ridge, a persistent
anticyclone -- previously over the Four Corners area including NM --
will reorganize and retrograde slightly westward, becoming centered
over the Monument Valley region of AZ/UT by the end of the period.
Meanwhile, a synoptic-scale trough -- apparent in moisture-channel
imagery from James Bay to southern MN and northern IA -- will pivot
across the Upper Great Lakes and adjoining states through this
evening. By 12Z, this trough should extend from central QC to the
Lower Great Lakes and upper Ohio Valley region.

A large area of cyclonic flow -- generally weakening with outward
extent from jet cores over the Great Lakes States and Northeast --
should cover much of the CONUS east of the Rockies and north of the
Gulf Coast States. On its southwestern periphery, strong difluence
will persist over the central/southern High Plains and much of TX.
Within and beneath that, a prominent MCV was apparent in radar-
reflectivity composites northwest of OKC. This feature is forecast
to drift southeastward over central/southeastern OK today, then
pivot eastward into southern AR overnight.

At the surface, 11Z analysis showed a cold front from southern QC
across LAKE Ontario, northwestern OH, central IN, southern IL,
south-central MO, southeastern KS, northwestern OK, the TX
Panhandle, and central/southeastern NM. The cold front is, and will
continue to be, diffused along segments of its extent by
baroclinicity from outflows of varying sizes. Still, in general, it
should reach western New England, the Delaware Valley, western VA,
middle TN, southern AR, to a weak frontal-wave low over north- central/northeast TX by 00Z. By 12Z, the front should extend from
near Cape Cod to central/eastern VA, north-central MS, and southern
AR, with a low lingering over northeast TX near or even somewhat
behind the MCV.

...Mid-Atlantic to New England...
Scattered to widely scattered thunderstorms are expected to develop
initially during midday near the cold front, then through the
afternoon ahead of the cold front (especially over higher terrain
and near prefrontal troughing in the boundary layer). Convective
coverage and intensity should increase as this activity moves
eastward to northeastward across the outlook area, forming a blend
of discrete storms, clusters and lines. Damaging gusts will be the
primary hazard, and several gusts above severe limits are possible
as well.

As the mid/upper-level synoptic trough approaches, deep-layer
southwest flow and shear will strengthen over the area, with the
mean-wind and deep-shear vectors oriented along to slightly
rightward of the axes of convective forcing. This will support the
mixed modes, which may include isolate supercell structures as well.
Overall organization will be aided by 30-40-kt effective-shear
magnitudes from central PA northeastward, and 20-30 kt farther south
and southwest. Meanwhile, the greatest buoyancy should reside over
the coastal Mid-Atlantic amid rich moisture and strong diurnal
heating. Although midlevel lapse rates are forecast to be very weak
(near or even less than moist-adiabatic in some layers), ambient
low-level theta-e and diabatic heating should drive MLCAPE into the
1000-1500 J/kg range over most of the region, and around 2000 J/kg
near the coast -- all atop well-mixed subcloud layers supporting
downdraft accelerations.

...Central/southern High Plains...
Widely scattered to scattered thunderstorms -- some quickly evolving
to outflow-driven, forward-propagating clusters -- should form this
afternoon over the Sangre de Cristos, Front Range, Laramie Range,
and attendant foothills/ridges. Damaging to isolated severe gusts
will be the primary concern, though isolated severe hail also is
possible.

Activity should form first over the mountains, where heating of high
terrain and at least marginal moisture will combine to
preferentially erode MLCINH. Lee troughing should develop over the
High Plains late tonight, but before then, a substantial, post-
frontal upslope/easterly flow component generally will prevail in
low levels. This will aid in lift and storm-relative boundary-layer
winds available to convection moving generally southeastward out of
the higher terrain. An axis of low-level moisture will correspond
well to a buoyancy axis as well, with peak MLCAPE around 1000-1500
J/kg in a corridor roughly from the NE Panhandle to western KS by
21Z, then gradually diminishing as nocturnal cooling occurs and
outflow impinges on parts of the area from the west. Modest
midlevel winds and weak shear should exist over most of this area,
despite strong directional change with height in low/middle levels.
Steep low/middle-level lapse rates -- near dry adiabatic in the
boundary layer -- will support strong-severe gust potential in the
most vigorous cells/clusters.

...North TX to central AR...
Widely scattered to scattered showers and thunderstorms should
develop over a vast area along and southeast of the front this
afternoon, southwestward from the outlook in the Atlantic Seaboard
across the Ohio/Tennessee Valleys, Southeast CONUS, and Mid-South to north/central TX. Most of this activity will be in a weak-shear but moisture-rich setting.

While isolated, pulse-severe downbursts cannot be ruled out with the
most intense activity anywhere in those regions, the greatest
potential concentration of both convection and at least marginal
severe potential appears to be over parts of north-central/northeast
TX into central AR, along and either side of the I-30 corridor. A
combination of lift along the front and prefrontal outflows, with
enhanced convergence in the MCV's mass response, and strong warm
sector diurnal heating, will strip away MLCINH this afternoon and
favor relatively dense development. Additional activity should form
along both colliding outflow/differential-heating boundaries and the leading-edge/forced-ascent zone of any clusters' cold pools that can
surge into the high-theta-e preconvective boundary layer. Upper 60s
to low 70s F surface dewpoints will support MLCAPE in the 2000-3000
J/kg range (locally higher), with well-mixed subcloud layers despite
the rich moisture. Weak vertical shear will limit the overall
organization of the threat.

..Edwards/Broyles.. 07/17/2024

$$
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ACUS01 KWNS 180552
SWODY1
SPC AC 180551

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1251 AM CDT Thu Jul 18 2024

Valid 181200Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EASTERN NORTH
CAROLINA INTO FAR SOUTHEAST VIRGINIA...

...SUMMARY...
Isolated strong to severe thunderstorms are possible Thursday
afternoon across parts of north-central Montana and the central and
southern High Plains. Isolated to scattered severe thunderstorms are
also expected from the southern Appalachians into eastern North
Carolina.

...Synopsis...
Early-morning surface observations show a diffuse cold front draped
from the Mid-Atlantic region into the southern Plains. This feature
is expected to slowly push south over the next 24 hours, as surface
high pressure builds over the Plains/Midwest in the wake of an eastward-tracking upper wave. A reservoir of upper 60s to low 70s
dewpoints lies to the south of the cold front, and while mid-level
lapse rates are fairly modest (based on 00 UTC soundings), diurnal
heating into the mid 80s should be sufficient to promote
thunderstorm development along the front by early afternoon.
Thunderstorm coverage is expected to be somewhat more focused across
the southern Appalachians into the Carolinas, as ascent associated
with a weak mid-level perturbation (currently over the mid-MS
Valley) overspreads the region at peak heating. To the west,
isolated to scattered thunderstorms appear likely within an upslope
flow regime along the central Rockies and ahead of a shortwave
trough over northern Montana.

...Carolinas...
The synoptic cold front is currently forecast to be along the VA/NC
border by around mid-day. Thunderstorm development along the front
appears probable by around 18 UTC, as temperatures warm into the low
80s and ascent from a subtle mid-level impulse overspreads the
region. Large hail may be an initial concern depending on storm
coverage along the front, but storm motion and deep-layer shear
vectors along and/or towards the cool side of the boundary will
likely promote upscale growth by mid/late afternoon. As this occurs,
the potential for strong to severe winds will increase downstream
across eastern NC and far southeast VA. Latest CAM guidance shows
reasonably good agreement in the development of a squall line, and
while deep-layer shear will not be overly strong (around 25 knots),
heating ahead of the line should yield moderate buoyancy with MLCAPE
reaching up to 2500 J/kg that will promote robust convection capable
of damaging gusts. The coverage of this threat appears sufficient to
warrant higher (15%) wind risk probabilities.

...Central to southern High Plains...
Another day of easterly upslope winds along the southern to central
Rockies is anticipated as a surface high to the east builds. Latest
upper-air analyses show the east slopes of the Rockies lie on the
periphery of a plume of relatively steep (7+ C/km) lapse rates. This
should support isolated to scattered thunderstorm development by mid
to late afternoon. Adequate deep-layer shear will be in place to
promote storm organization, including the potential for a supercell
or two if more discrete storm modes can be realized. However, weak
low-level storm-relative winds and steep low-level lapse rates will
likely favor cold-pool driven storm propagation and the development
of multiple convective clusters with an attendant severe-wind risk.

...Montana...
A shortwave impulse is evident in early-morning water-vapor imagery
across the Pacific Northwest. This feature is expected to crest the
apex of a stout upper ridge over the next 24 hours. Advected
precipitable water imagery shows a diluted plume of monsoonal
moisture ahead of this wave, which should provide adequate mid-level
moisture for thunderstorm development by late afternoon. While
buoyancy will be very modest (around 500 J/kg SBCAPE), 30 knot
mid-level flow atop easterly low-level winds should provide adequate
deep-layer wind shear for some storm organization, most likely into
somewhat cohesive clusters given deep-boundary layer mixing that
will favor strong cold pool production. Such clusters may be capable
of strong to severe winds as they push east across north-central MT.

..Moore.. 07/18/2024

$$
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ACUS01 KWNS 181254
SWODY1
SPC AC 181252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Thu Jul 18 2024

Valid 181300Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF NORTH
CAROLINA AND EXTREME SOUTHEASTERN VIRGINIA...

...SUMMARY...
The greatest concentration of damaging gusts today should be over
portions of North Carolina and extreme southeastern Virginia.

...Synopsis...
The upper-air pattern will remain dominated by mean ridging over the
West (from AZ-AB and northward to the Arctic) and troughing in the
East. The large-scale ridge will be anchored by a high slowly
retrograding westward from the Four Corners toward the southern
Great Basin. Just upstream from the ridge, a strong shortwave
trough was apparent over the ID Panhandle and adjoining parts of BC.
This feature should move slowly eastward through the mean ridge
today, reaching northwestern MT and southern AB by 00Z, then turning southeastward over central MT tonight.

A strong cyclone over northern tip of QC will dig southward over
northern QC through the period, with little movement to the mean
trough extending southwestward across the lower/mid Mississippi
Valley. Within the associated cyclonic flow, a positively tilted synoptic-scale trough -- evident in moisture-channel imagery from central/southwestern QC across the neck of ON to Lower MI and IN --
should pivot eastward and become more positively tilted as the
northern part accelerates. By the end of the period, the trailing
part of this trough should extend across eastern New England to NJ.
A subtle, positively tilted perturbation -- now over eastern parts
of KY/TN -- should move east-northeastward to eastern VA and
northeastern NC today.

In between the longwave trough and ridge, northwesterly to northerly
flow aloft will prevail across the Great Plains, with small/low-
amplitude shortwaves and vorticity lobes exiting the mean-ridge
position over the northern Rockies. Difluent upper-level flow will
extend across most of the Plains States, but should be especially
prominent from the central High Plains southeastward to the TX Gulf
Coast.

Surface analysis at 11Z showed a cold front from southeastern QC
across the Hudson Valley to central/western VA, middle TN, central
AR, north-central TX, the TX Permian Basin, and central NM. This
boundary should move slowly southeastward and southward across the
Atlantic and Gulf Coast States today, reaching near a line from ORF-SPA-MGM-PIB-SAT by 00Z. The segment of the front from south TX
to AL should stall overnight, while the remainder drifts east-
southeastward. A lee trough was drawn from southeastern MT across
eastern WY/CO/NM just est of the mountains, and should remain near
its present position through the day.

...NC/VA and vicinity...
Thunderstorms may develop from midday through this afternoon in the
higher terrain of western NC and southwestern VA, as well as weak
surface troughing to the east, and the front on the north side of
the outlook. While at least isolated damaging gusts and large hail
will be possible over a broad area from the high-terrain genesis
zone to the Tidewater and northern SC, the greatest concentration
and organization of convection (and potential for damaging to severe
gusts) should be over portions of central/eastern NC south of the
front, and perhaps extreme southeastern VA near the NC border along
the front.

Activity will be aided by weak large-scale ascent preceding the
southern Appalachians shortwave trough, acting in concert with
string diurnal heating to steepen low/middle level lapse rates. A
deep summertime troposphere and rich low-level moisture (dewpoints
commonly in the 70s over and east of the Piedmont) will further
contribute to favorable buoyancy, with peak MLCAPE reaching the
2000-3000 J/kg range over the "slight risk" area of greatest
unconditional severe probabilities. 25-35-kt westerly to
west-southwesterly flow aloft should encourage storm motion into
that optimal moisture/CAPE, with upscale aggregation possible into forward-propagating clusters or a squall line. That would maximize damaging-wind potential until activity moves offshore this evening.

...Central/southern High Plains...
Another afternoon of scattered to widely scattered thunderstorm
development is likely near the lee trough, and over higher terrain
near the eastern rim of the Rockies. Additional foci may include
parts of the Cheyenne/Palmer/Raton Mesa ridges, and an
outflow/differential heating boundary from ongoing/non-severe
convection over the TX Panhandle/northeastern NM region.
Thunderstorms should move mainly to the south, with some
southeastward or even southwestward tracks (for rightward-deviant
cells) possible. Isolated severe gusts and large hail will be
possible, with small-scale clustering potentially increasing severe probabilities locally.

From the lee trough eastward, low-level flow will be weak, but with
a predominant easterly surface component, helping to maximize both
low-level lift and (through strong veering with height) deep shear. Effective-shear magnitudes of 35-45 kt and somewhat long, nearly
straight low-level hodographs are progged east of the lee trough,
supporting the potential for a blend of multicell and supercell
modes. However, modest mid/upper winds are forecast, keeping storm
motion slow outside of areas where cold pool aggregate and
accelerate storm-translation vectors well past those suggested by
ambient winds. The corridor of riches low-level moisture will cover
about the eastern half of the outlook, within which peak/
preconvective MLCAPE of 1000-2000 J/kg will be possible. However,
MLCINH also will increase with eastward extent, with time this
evening, and with lower surface elevation. As such, activity should
become weaker and more isolated tonight.

...Portions of MT...
Widely scattered to scattered, high-based thunderstorms are expected
to develop this afternoon over higher terrain of west-central MT, as
three processes overlap:
1. Preceding the shortwave trough, large-scale DCVA/ascent/cooling
aloft over spreads the area;
2. Diurnal heating preferentially erodes low-level MLCINH over
higher elevations, and builds deep/well-mixed subcloud layers with
40s to low 50s F surface dewpoints, beneath around 300-700 J/kg
MLCAPE;
3. Modest low-level convergence continues near a lee trough just
east of the mountains, with weak closed-low development possible at
the surface over north-central MT.

As this activity shifts eastward, isolated severe gusts may occur.
Aggregating outflows may permit an arc of strong/locally severe
outflow to organize, with convection along or behind the leading
edge. Lack of more robust moisture/buoyancy should limit the
overall threat, and contribute to enough stabilization of the
foregoing boundary layer to weaken the activity during the evening.

..Edwards/Broyles.. 07/18/2024

$$
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ACUS01 KWNS 201253
SWODY1
SPC AC 201252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Sat Jul 20 2024

Valid 201300Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE SOUTHEAST AND CENTRAL TO SOUTHERN HIGH PLAINS...

...SUMMARY...
Strong to isolated severe thunderstorms are possible over parts of
the Southeast and central to southern High Plains, mainly from
mid-afternoon to evening.

...Synopsis...
The large-scale pattern in mid/upper levels will continue to feature
longwave troughing over eastern North America, and ridging in the
West. The latter will be anchored by an anticyclone -- now centered
over AZ -- that will retrograde slowly northwestward through the
period. This process -- and a broad field of minor shortwaves and
vorticity lobes in northerly/northwesterly flow -- will contribute
to net height falls over much of the central CONUS. A downstream
shortwave trough was evident in moisture-channel imagery from the
lower Ohio Valley southwestward across western TN to eastern LA.
This perturbation should move eastward across the Tennessee Valley
region through midday, then over parts of GA and the Carolinas
through this evening.

The 11Z surface map showed a weak, quasistationary frontal zone from
southern VA across eastern TN, western MS, central LA, and
south-central TX. Except where locally reconfigured by convection,
this frontal zone should remain quasistationary, while gradually
losing definition. A lee trough -- drawn from western MT to western
SD and western KS, should remain nearly in place through the day,
with slight shifts possible in late afternoon toward strongly heated
areas.

...Southeast...
Widely scattered to scattered thunderstorms should form and move
northeastward over the area this afternoon, as large-scale lift
ahead of the approaching trough spreads atop a richly moist,
strongly heated, weakly capped boundary layer. Damaging to isolated
severe gusts are possible. Some of the activity may aggregate into
loosely organized clusters that maximize damage potential locally.
Somewhat enhanced mid/upper flow will contribute to spotty
effective-shear magnitudes of 30-35 kt, aiding in organization of
some of this activity. The inflow layer will be characterized by
surface dewpoints commonly in the low-mid 70s F and favorable lapse
rates from surface heating beneath a deep troposphere. As such, and
despite the lack of large mid/upper-level lapse rates, a deeply
buoyant preconvective profile should take shape, with peak MLCAPE in
the 2000-3000 J/kg range over the Low Country/coastal plain, and
1500-2500 J/kg across the Piedmont.

...Central/southern High Plains...
Isolated to scattered thunderstorms are expected to develop this
afternoon along the Front Range/Sangre de Cristo corridor from
southeastern WY to NM, as well as over the Raton Mesa, near the lee
trough, and along leftover outflow/differential-heating boundaries
from prior overnight/morning convection. Isolated severe gusts and
hail are possible.

This activity will be moving into a generally less-buoyant airmass
than the previous day, thanks to extensive prior convection and
outflow over much of the region. Nevertheless, sufficient diurnal
heating and residual boundary-layer moisture are expected to support
both well-mixed subcloud layers and enough CAPE for deep convection.
Though outflow-driven forward propagation may contribute to erratic
storm motions locally, a general southeastward to southward
translation is forecast, given the ambient midlevel winds. Although
strong directional shear is expected, forecast soundings indicate
much of this will be in the form of backing with height instead of
veering, and with weak low/middle-level winds limiting vertical bulk
shear. Peak afternoon MLCAPE of 1000-1500 J/kg is possible near an
irregularly defined moist axis extending from the eastern Panhandles
and southwestern KS northeastward, and over eastern CO. Buoyancy
will diminish atop a drier, more deeply mixed layer westward toward
the mountains. Overall, convection should diminish in coverage and
intensity throughout the evening.

..Edwards/Broyles.. 07/20/2024

$$
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