ACUS01 KWNS 171642
SWODY1
SPC AC 171640

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1140 AM CDT Sat Jun 17 2023

Valid 171630Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE CENTRAL AND SOUTHERN PLAINS....

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE
SOUTHERN US...AND PARTS OF WESTERN IOWA....

CORRECTED FOR GEOGRAPHICAL DESCRIPTION

...SUMMARY...
Severe thunderstorms are possible over a vast area from Colorado to
Florida, and central Texas to the lower Missouri Valley. Within
that, a focused corridor of threat for damaging hail, significant
wind damage, and a few tornadoes, extends from southeastern Colorado
to northwestern Arkansas, and into north Texas.

...Southeast CO to Arkansas...
Morning water vapor imagery shows a well-defined shortwave trough
over southwest CO. This feature will cross the Rockies and begin
affecting the High Plains this afternoon, promoting scattered
thunderstorms off the high terrain and foothills. Initial supercell
storms over southeast CO will be in a region of steep mid-level
lapse rates and moderate CAPE, favorable for large hail. As
activity moves/builds eastward into southwest KS, the northern TX
Panhandle, and northwest OK, it will encounter high CAPE values and increasingly strong low-level winds. Supercells with very large
hail, significant wind damage potential, and a few tornadoes may
affect this area during the evening. Upscale growth of this cluster
of storms into a fast-moving bowing complex remains likely, with
activity moving across northern OK into northwest AR tonight.

...North TX...
A 50-60 knot westerly mid-level jet max is accompanying the
aforementioned shortwave trough over CO. This wind max will move
across the TX Panhandle this evening, with enhanced forcing for
ascent affecting the dryline over west TX. This will lead to rapid
supercell development in a very moist and unstable environment.
Very large hail and damaging winds are expected with the stronger
cells. Several CAM solutions favor splitting supercells, with
left-movers tracking northeastward toward the Red River through the
evening with a continued risk of significant severe. Therefore have
extended the ENH risk into these areas.

...MS/AL/FL...
Morning model guidance shows a subtle shortwave trough currently
over west TN tracking southeastward into AL, with an associated
40-50 knot mid-level wind max moving across MS. Strong daytime
heating of a very moist boundary layer ahead of these features
should result in scattered severe thunderstorm development by mid
afternoon over parts of southeast MS, southern AL, and the FL
Panhandle. Given the strength of the deep-layer shear, supercell
structures capable of large hail and damaging winds are expected. A
tornado or two is also possible as the storms approach the coast
late this afternoon. Activity should move offshore after dark.

...Western IA...
A well-defined remnant MCV is noted this morning over
central/eastern NE. Southerly low-level winds ahead of this
circulation will maintain near 70F dewpoints over western IA, where
strong heating is occurring. This should lead to scattered
afternoon thunderstorms. Forecast soundings show sufficient
vertical shear for organized multicell or occasional supercell
storms capable of hail and damaging winds. Therefore have added a
SLGT risk to this region for this afternoon and early evening.

..Hart/Gleason.. 06/17/2023

$$

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ACUS01 KWNS 250120
SWODY1
SPC AC 250118

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0818 PM CDT Sat Jun 24 2023

Valid 250100Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO
THE OVERNIGHT HOURS ACROSS PARTS OF WESTERN
MINNESOTA...IOWA...NORTHEASTERN MISSOURI...AND NORTHWESTERN INTO
CENTRAL ILLINOIS...

CORRECTED FOR HAIL PROBABILITY GRAPHIC

...SUMMARY...
Isolated strong to severe thunderstorm development remains possible
into the overnight hours across a broad area from parts of the
southern Great Plains into the Upper Mississippi Valley. One or two
clusters of storms could still develop near or just east of the
middle Mississippi Valley through daybreak.

...01Z Update...
Models indicate that a modest cyclone (currently centered at the
surface) over southeastern North Dakota will gradually occlude and
weaken overnight while gradually reforming east-southeastward into
the Upper Midwest. A trailing surface cold front is forecast to
surge southeastward/southward through much of the lower Missouri
Valley and central Great Plains, while a dryline lingers across
parts of northwest Texas/western Oklahoma.

Strongest mid/upper support for upward vertical motion will remain
focused within a strongly difluent regime to the southeast of the
mid-level low, downstream of a seasonably strong digging mid-level
jet (50+ kt around 500 mb) across and northeast of the lower
Missouri Valley. The leading edge of the return of seasonably moist
air on southerly flow beneath this regime is contributing to
moderately large CAPE in the presence of strong deep-layer shear.
Low-level forcing for ascent has remained weak, but various model
output suggests that lower/mid-level warm advection will strengthen
across southeastern Iowa through central Illinois this evening,
where storms could still increase and consolidate into an organizing
cluster.

As the larger-scale mid-level troughing continues to dig overnight,
models suggest similar, but perhaps weaker, forcing for ascent may
develop across parts of southeastern Missouri and southern Illinois
into the lower Ohio Valley/Mid South toward daybreak. Inflow of
seasonably moist air with large potential instability will
contribute to an environment at least conditionally supportive of
another organizing cluster of storms posing a risk for severe hail
and wind.

..Kerr.. 06/25/2023

$$

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ACUS01 KWNS 291720
SWODY1
SPC AC 291718

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1218 PM CDT Thu Jun 29 2023

Valid 291630Z - 301200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF ILLINOIS...

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
FRONT RANGE AND CENTRAL HIGH PLAINS...

CORRECTED FOR IMPROPERLY FORMATTED HAIL POINTS PRODUCT

...SUMMARY...
Swaths of damaging winds of 60-80 mph, large hail, and a couple of
tornadoes are expected today across Illinois and western/southern
Indiana. Other severe storms with large hail and damaging winds
gusts are expected across the Tennessee Valley, as well as the
central High Plains.

...Midwest/Tennessee Valley including MO/IL/IN/KY/TN...
An upper-ridge peripheral zone of locally intense/significant severe
weather is expected today, especially across Illinois into
western/southern Indiana and west-central Kentucky southward across
the Tennessee Valley.

A prominent/relatively large MCS across northeast Missouri and
northwest Illinois at late morning will continue to progress
eastward through a very unstable air mass, with potential for
significant wind gusts, occasional hail, and some convective
line-embedded tornado risk. The eastern extent of the most intense
severe weather is a bit uncertain given current air mass
characteristics across far eastern Illinois into Indiana in the wake
of early day storms, but severe weather can nonetheless be expected
through the afternoon into evening.

Another focused corridor of severe weather will exist from the Lower
Ohio Valley southward into the Tennessee Valley, highlighted with a
leading south/southeastward-moving MCS, as well as regenerative
potentially severe convection on its trailing west/northwest flanks.
Bouts of damaging winds and severe hail will be possible into this
evening in this corridor.

...Front Range/Central Plains this afternoon/evening...
Have upgraded portions of the Front Range and southeast Wyoming/far
western Nebraska and northeast Colorado to an Enhanced Risk. Severe
storms are expected later this afternoon into tonight within the
post-frontal upslope low-level flow across eastern
Colorado/southeast Wyoming, with appreciable low-level moisture
having spread westward to the Front Range overnight. Breaks in the
low clouds will support moderate buoyancy by mid afternoon (MLCAPE
of 1000-2000 J/kg), when thunderstorm development will become more
probable on and immediately east of the higher terrain from Colorado
into southeast Wyoming. The moderate buoyancy and relatively long
hodographs with effective bulk shear in excess of 40 kt will support
supercells capable of producing large hail of 2-3 inches in
diameter, along with some tornado potential. Upscale growth into a
few clusters will be possible this evening, with an attendant threat
for isolated severe-caliber winds. Some of the evening convection
may persist into the overnight hours across southern
Nebraska/northern Kansas with some threat for isolated large hail
and wind damage, potentially as far east as southwest Iowa/northwest
Missouri.

..Guyer/Smith.. 06/29/2023

$$

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ACUS01 KWNS 230103
SWODY1
SPC AC 230102

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0802 PM CDT Sat Jul 22 2023

Valid 230100Z - 231200Z

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

CORRECTED FOR 5% HAIL LINE

...SUMMARY...
Thunderstorms associated with large hail and wind damage will be
possible this evening in parts of the central Plains. Marginally
severe storms will also be possible in the southern High Plains, mid
Missouri Valley, upper Mississippi Valley, Southeast and Arizona.

...Central and Southern Plains/Mid Missouri and Upper Mississippi
Valleys...
Northwesterly mid-level flow is evident across the central U.S. this
evening, with a subtle shortwave trough moving southeastward across
the mid Missouri and upper Mississippi Valleys extending into the
central Plains. Ahead of the trough, a moist and unstable airmass is
in place from Kansas northeastward into Iowa, with surface dewpoints
in the 60s F contributing to moderate instability. Scattered
thunderstorms are ongoing within this airmass. The greatest
convective coverage is located in the central Plains, where
thunderstorm development will likely continue for much of the
evening.

An instability maximum is currently analyzed by the RAP in western
Kansas, where MLCAPE is estimated to be around 2500 J/kg. The
Goodland, Kansas WSR-88D VWP is near the instability max, and has
had 0-6 km shear in the 55 to 65 knot range over the last hour. This
will continue to support supercell development over the next few
hours across western and northern Kansas. In addition, the RAP shows
an elevated mixed layer extending from the central Rockies into the
central Plains, where 700-500 mb lapse rates are estimated to be in
the 7 to 7.5 C/km range. This thermodynamic environment will be
favorable for large hail with the more intense cores. Hailstones of
greater than 2 inches in diameter will be possible early this
evening in parts of western Kansas. In addition, a wind-damage
threat will accompany the more intense cells.

Outside of the slight risk area, moderate instability is currently
analyzed across parts of the southern High Plains, and in the mid
Missouri and upper Mississippi Valleys. Although deep-layer shear
will be adequate in these areas for a marginal severe threat,
isolated convective coverage and decreasing instability will likely
cause the severe threat to diminish by mid to late evening.

...Southeast...
Westerly mid-level flow is located across much of the Southeast this
evening. At the surface, a cold front is located from south-central
Mississippi eastward into western Georgia. To the south of the
front, surface dewpoints in the lower to mid 70s F are contributing
to moderate instability, mainly along the immediate Gulf Coast.
Strong thunderstorms are ongoing along the northern edge of this
unstable airmass. Although deep-layer shear appears to be marginal
for severe storms across much of the Gulf Coast, low-level lapse
rates are steep in many of the coastal areas according to the RAP.
This should be enough for an isolated wind-damage threat for another
hour or two this evening. The greatest potential will be in southern
Louisiana.

...Arizona...
A mid-level anticyclone is currently located over the Desert
Southwest. Scattered thunderstorms are ongoing from central New
Mexico into southwest Arizona, where an axis of instability is
located. Although deep-layer shear is relatively weak across this
area, 0-3 km lapse rates are estimated to be in the 9 to 10 C/km
range, according to the RAP. This will likely aid downdraft
acceleration with a few of the stronger cells this evening,
contributing to an isolated wind-damage threat.

..Broyles.. 07/23/2023

$$

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ACUS01 KWNS 040110
SWODY1
SPC AC 040108

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0808 PM CDT Thu Aug 03 2023

Valid 040100Z - 041200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
CO INTO NORTHWEST/NORTH-CENTRAL KS AND SOUTHWEST NE...

CORRECTED FOR TORNADO GRAPHIC

...SUMMARY...
Storms capable of producing severe wind gusts remain possible this
evening into late tonight across parts of the central High Plains.

...Central Plains...
Clusters of strong to occasionally severe storms are ongoing this
evening across parts of the central High Plains, with measured
severe gusts noted earlier near/east of Pueblo and Colorado Springs.
The potential remains for notable upscale growth later this evening
into parts of western KS and southwest NE, as ongoing convection
moves into an increasingly moist and unstable environment. Should
this occur, the potential for severe gusts will spread eastward
later tonight, with the threat possibly reaching
north-central/northeast KS before the end of the period.

...Parts of NY/VT...
Storms are gradually increasing in coverage this evening across
parts of central/northern NY, in response to a midlevel shortwave
trough moving across southern Quebec. Storms have thus far struggled
to remain organized, but weak to moderate instability and marginally
favorable deep-layer shear will support a threat for isolated hail
and damaging wind tonight, with multiple rounds of convection
possible.

...Southeast MO into western TN and northern MS/AL...
Another round of storms may erupt late tonight across parts of
southeast MO, as a modestly increasing low-level jet impinges upon a
reservoir of strong buoyancy. Storms will likely tend to remain
somewhat elevated, but at least isolated hail and damaging gusts
will be possible as one or more clusters move southeastward
overnight into parts of western TN and potentially northern MS/AL.

..Dean.. 08/04/2023

$$

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ACUS01 KWNS 060644
SWODY1
SPC AC 060642

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0142 AM CDT Sun Aug 06 2023

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
MIDWEST SOUTHWARD ACROSS THE OHIO AND TENNESSEE VALLEYS...

CORRECTED SIG HAIL AREA

...SUMMARY...
Widely scattered severe thunderstorms are expected today over parts
of the Midwest, Ohio and Tennessee Valleys. Damaging gusts will be
possible over much of the region, with damaging hail most likely
from eastern Missouri into Illinois.

...Synopsis...
A shortwave trough will move east/southeast from IA into IL through
the period, with a belt of 50 kt midlevel winds extending from KS
into the lower OH Valley. At the surface, low pressure will move
from IA into IL, with a cold front extending southwestward across MO
and into OK during the day. Preceding the main upper trough, a
leading disturbance will move slowly from IN into OH, with a
boundary near the OH Valley lifting north as a warm front into
central IL by 00Z. South of these areas, a moist and unstable air
mass will remain over much of the Southeast.

...AR eastward across the TN Valley...
Models indicate that areas of storms may be ongoing over parts of AR
this morning, with possible continuation and/or outflow pushing east
into MS, TN, and AL during the afternoon. Along with this possible
forcing mechanism, westerly winds aloft will also increase through
the period. Strong heating will occur over the region ahead of this
possible activity, and forecast soundings depict tall CAPE profiles
with ML values over 3000 J/kg. Clusters of thunderstorms thus appear
likely to redevelop during the afternoon, with locally damaging
outflow winds possible.

...Eastern IA and MO into IL...
Rain and thunderstorms will likely be ongoing over central and
eastern IA early in the day near the surface low. This will likely
limit heating for much of this area. Farther south into MO and
eventually into central IL, strengthening westerly winds associated
with the upper trough will aid boundary-layer mixing with stronger
heating occurring. A deep-layer theta-e plume will likely develop
from MO into IL, with both wind and hail potential as storms develop
after about 20Z close to the IA/MO/IL border. Additional activity is
likely to develop along the cold front southward across the mid MS
Valley, with expanding storm coverage into much of IL, southern IN
and parts of KY during the evening. A few storms may produce
damaging hail over 2.00" diameter.

..Jewell/Moore.. 08/06/2023

$$

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ACUS01 KWNS 070601
SWODY1
SPC AC 070600

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0100 AM CDT Mon Aug 07 2023

Valid 071200Z - 081200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
THE EASTERN U.S....

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM ALABAMA AND
GEORGIA NORTHWARD ACROSS NEW YORK...AND OVER THE CENTRAL HIGH
PLAINS...

CORRECTED FOR FORECASTER NAME

...SUMMARY...
Severe thunderstorms are expected across much of the eastern U.S.
today, with the greatest risk across West Virginia, much of
Virginia, Maryland, and southern Pennsylvania. Widespread damaging
winds, hail, and a few tornadoes are anticipated. Concentrated areas
of wind damage are also expected over parts of the southern
Appalachians, including parts of Alabama, Georgia, and the
Carolinas.

...From eastern KY/TN and OH across
WV...VA...MD...DE...PA...NJ...southern NY...
A complicated and active severe weather setup is forecast today,
with severe storms likely starting relatively early possibly from
southern OH across eastern KY and TN. The midlevel speed max is
forecast to travel eastward roughly along the KY/TN border, with 500
mb speeds over 50 kt and 300 mb around 80 kt. Little heating will be
required within the theta-e plume and beneath cooling temperatures
aloft, and scattered storms are expected by around 18Z over these
areas. Shear will favor supercells, and mesoscale factors such as
potential residual outflows could enhance low-level shear, or,
stabilize portions of the area. Existing storms as of 06Z Monday
near the OH River will likely play a role into late/mid morning
today.

Otherwise the entire area extending eastward toward the Coast will
destabilize ahead of the upper trough, with activity most likely
moving strengthening across WV and moving rapidly eastward into PA,
MD, and VA. Forecast soundings show the potential for a few
supercells, with modest low-level SRH. However, tornado threat will
depend on storm mode, and many models depict a squall line. Even so,
QLCS-type tornadoes will be possible along with the widespread
damaging winds. In addition, more isolated activity developing
northward across NY may also yield a tornado or two, as shear will
be favorable but with lesser instability.

...Eastern TN...AL...GA...Carolinas...
Strengthening west to northwest winds around the upper trough and
strong heating will likely lead to relatively widespread damaging
wind potential as storms form from TN into northern MS and AL around
midday. An expansion of storms producing outflow is likely across
most of GA and parts of the Carolinas through the afternoon as this
activity moves rapidly east/southeastward, possibly reaching the SC
Coast before 00Z.

...Central High Plains...
Moderate west/northwest winds aloft will exist from CO/WY into the
central Plains, with a belt of 70+ kt winds at 300 mb across
northern NM into OK/KS. At the surface, a weak ridge will exist over
the central Plains, but lee troughing will develop during afternoon
from western NE across eastern CO and into northeast NM. Storms
producing large hail are likely to form off the Front Range and
mature into severe storms producing hail and locally damaging gusts.
Other storms will form from southeast CO into NM, similarly moving
eastward across the Panhandles with lengthy hodographs favoring
hail.

..Jewell/Moore.. 08/07/2023

$$

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ACUS01 KWNS 080550
SWODY1
SPC AC 080549

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1249 AM CDT Tue Aug 08 2023

Valid 081200Z - 091200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTRAL HIGH
PLAINS...

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

CORRECTED FOR ERRONEOUS THUNDER LINE DIRECTION

...SUMMARY...
Scattered severe thunderstorms are possible across portions of the
central High Plains this afternoon into tonight. Large to very
large hail, along with a risk for a tornado and widely scattered
severe gusts, will be the potential hazards. Scattered severe
thunderstorms are also expected through the day across portions of
the Southeast.

...Synopsis...
An unseasonably strong upper wave is noted in overnight water-vapor
imagery lifting to the northeast across the New England region. In
its wake, a broad northwesterly flow regime is in place from the
Pacific Northwest to the southeastern states. Several disturbances
are embedded within this mean flow regime from the High Plains into
the northern Great Basin. These disturbances are expected to
propagate to the southeast over the next 24 hours, and will be the
impetus for severe weather potential for the High Plains and
Southeast.

...Central Plains/High Plains...
The upper wave over the northern Great Basin is forecast to move
into the central Rockies by 00-06 UTC this evening. As this occurs,
modest lee troughing will support southeasterly return flow, which
should allow for air mass recovery in the wake of early morning
convection. The combination of southeasterly low-level flow under
40-50 knot zonal flow aloft will yield nearly-straight hodographs
featuring strong deep-layer shear (on the order of 50 knots). This
zonal flow will foster eastward advection of steep 700-500 mb lapse
rates sampled upstream by 00 UTC soundings, which when combined with
low-level moistening, will result in MLCAPE values near 2500-3000
J/kg by late afternoon.

Initially discrete cells are expected to develop within the upslope
flow regime across northeast CO to southeast WY and the NE
Panhandle. Given the aforementioned thermodynamic/kinematic
environment, splitting supercells appear likely. These will pose a
threat for very large hail (2+ inches in diameter) and a tornado or
two, as cells migrate into improving low-level moisture across
northwest KS. Consolidating outflow from storm interactions should
foster gradual upscale growth by late evening. Lift associated with
the ejection of the upper wave and a strengthening low-level jet
will aid in MCS organization overnight across KS with an attendant
severe wind risk.

...Southeast...
A convectively reinforced MCV is forecast to emanate from the
southern Plains into the lower MS River Valley and Southeast today.
One or more thunderstorm clusters associated with this feature will
likely be elevated at the start of the forecast period, posing a
severe hail risk across AR/northern LA. The convective threat will
transition to a damaging wind threat by late morning and early
afternoon across central MS/southern AL, where temperatures are
forecast to reach the low to mid 90s along and south of a residual
outflow boundary/cold front. Enhanced mid-level flow associated with
the MCV should provide adequate deep-layer shear for organized
convection. While a few semi-discrete cells are possible, one or
more organized clusters/lines appear probable as the system moves
into southern GA/north FL by late afternoon/early evening.

...New England...
A secondary surface low associated with the northeastern upper wave
is expected to meander northeast through the New England region
during peak daytime heating. Warming surface temperatures should be
adequate to support surface-based convection, and effective SRH on
the order of 100 m2/s2 in the vicinity of the low may allow for a
few transient mesocyclones with an attendant tornado threat.
However, this potential will be conditional on sufficient low-level
heating, which is uncertain given lingering precipitation and cloud
cover.

..Moore/Jewell.. 08/08/2023

$$

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ACUS01 KWNS 130818
SWODY1
SPC AC 130817

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0317 AM CDT Sun Aug 13 2023

Valid 131200Z - 141200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF SOUTHEASTERN KANSAS...FAR NORTHEASTERN OKLAHOMA...AND INTO THE
OZARKS VICINITY...

CORRECTED FOR DAY IN TEXT

...SUMMARY...
Severe thunderstorms are possible Sunday from portions of the
southern and central Plains into the Middle Mississippi, Lower Ohio
and Tennessee Valleys.

...Synopsis...
Ridging aloft will prevail over the western U.S. today, as well as
over the south-central and southeastern states. Meanwhile, a rather
vigorous mid-level short-wave trough will advance southeastward
across the northern and central Plains through the day, and into the
Upper Midwest overnight.

At the surface, an evolving cold front is forecast to progress
southeastward across the northern and central Plains. By sunset,
the front should extend south-southeastward from a weak low over the
eastern South Dakota vicinity to the Texas/Oklahoma Panhandles.
Meanwhile, a weak warm front should extend southeastward across
Missouri and into the Tennessee Valley area. Additionally, various
convective boundaries are forecast to reside over the
Kansas/Oklahoma/Missouri area. These surface features -- both
synoptic and convectively induced -- will contribute to the
likelihood for multiple rounds of convective activity through the
period, from the central Plains vicinity to the Mid
Mississippi/Lower Ohio/Tennessee Valley areas.

...Mid Missouri Valley to the Texas/Oklahoma Panhandles, and
eastward to the Tennessee/Kentucky vicinity...
A rather complex convective scenario is evident for today across the
primary risk area that extends from the Plains to western fringes of
the Appalachians. Convection will likely be ongoing at the start of
the period across portions of the Plains and possibly into the
Ozarks area. The storms should continue through the day, moving
eastward with time, reinforcing the various convective boundaries
across this area.

As daytime heating occurs on the periphery of these boundaries, and
along/ahead of the advancing cold front, additional storm
development is expected. Given the belt of generally 35 to 45 kt
mid-level westerlies atop the region, shear will be sufficient to
support potential for strong/locally severe storms, with hail and
locally damaging wind gusts the primary risks. Delineating any
potential area of more concentrated severe risk remains difficult at
this time, but one area where greater severe-weather coverage may
manifest is across the Ozarks vicinity. Along with a warm front
expected to lie across Missouri, a roughly west-to-east outflow
boundary may evolve -- and possibly become the effective focus for
multiple rounds of storms. With a corridor of enhanced (40 to 50
kt) west-southwesterly flow expected to lie atop this region,
episodic strong/damaging gusts are expected, which warrants
inclusion of 30% wind probability/ENH risk across this region. In
addition, with backed low-level flow expected to the cool side of
the aforementioned boundaries, corridors of enhanced low-level
veering/shear suggests potential for a few tornadoes.

Risk will likely continue through the evening and into the overnight
hours, as additional storms associated with the southeastward cold
frontal advance evolve/spread southward and eastward into early
Monday morning.

...New England...
Modest low-level moisture is expected to remain in place ahead of an eastward-advancing cold front. As diurnal heating peaks through the
afternoon, mid-layer CAPE around 1500 J/kg is expected to evolve,
supporting widely scattered afternoon storm development. With
mid-level westerlies around 40 kt expected across the area, shear
sufficient for organized storms suggests marginal hail and locally strong/damaging wind gusts will be possible with a few of the
strongest storms, before convection weakens into the early evening
hours.

..Goss/Lyons.. 08/13/2023

$$

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ACUS01 KWNS 072013
SWODY1
SPC AC 072012

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0312 PM CDT Thu Sep 07 2023

Valid 072000Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHEAST...

CORRECTED THUNDER LINE

...SUMMARY...
Thunderstorms -- some capable of producing locally damaging wind
gusts and marginally severe hail -- will continue across portions of
the Mid-Atlantic region and into New England into this evening.

...Discussion...
Current expectations with regard to the convective scenario through
tomorrow morning remain in line with prior reasoning. As such,
aside from minor line adjustments, the overall forecast will remain
unchanged with this outlook update.

..Goss.. 09/07/2023

.PREV DISCUSSION... /ISSUED 1110 AM CDT Thu Sep 07 2023/

...Synopsis...
A mid-level high, centered over the southeastern New Mexico
vicinity, appears likely to remain prominent through this period,
with large-scale ridging building to its north, through much of the
Rockies and adjacent Great Plains today through tonight.
Downstream, several perturbations, comprising weak but amplifying
larger-scale mid-level troughing east of the Mississippi Valley, are
forecast to remain generally progressive, though mid-level ridging
may continue to build near/east of the middle and northern Atlantic
Seaboard, in the wake of a modest cyclone migrating eastward across
portions of the Canadian Maritimes.

The two more significant perturbations include a remnant mid-level
trough forecast to slowly accelerate northeast of the lower Great
Lakes region through southern Ontario and Quebec, and a weak
developing mid-level low forecast to dig south-southeast of the
lower Ohio Valley through Alabama/Georgia by 12Z Friday. East of
these features, and ahead of a cold front which has already advanced
into the Appalachians vicinity (while stalling across parts of the
lower Mississippi Valley into southern Great Plains), deep-layer
southerly mean flow and shear will likely remain mostly rather
modest to weak (less than 20 kt). However, models do suggest that a
more subtle perturbation migrating north-northeast of the Blue Ridge
might contribute to a belt of modest south-southwesterly mid-level
flow along the western periphery of the building ridge, with at
least some signal that this could also become convectively augmented
by tonight.

...Atlantic Seaboard...
Seasonably moist air, beneath relatively steep
lower/mid-tropospheric lapse rates, likely will contribute to
sizable mixed-layer CAPE to the east of developing surface troughing
to the lee of the Appalachians. This could become supportive of
developing clusters of storms with potential to produce strong wind
gusts, as convection initiates and slowly propagates off the higher
terrain this afternoon. The most prominent and concentrated area of thunderstorm development still appears likely to be focused with the increasingly sheared short wave impulse and modestly strengthening
southerly mid-level flow (30+ kt in the 700-500 mb layer) across
eastern Pennsylvania and New York, and adjacent portions of the Mid
Atlantic and New England, through early evening. This may include
an upscale growing, and gradually organizing, thunderstorm cluster
or two which may eventually pose a risk of producing a swath of
strong to severe surface gusts.

...Lower Mississippi Valley/Gulf Coast vicinity...
Destabilization associated with a corridor of strong pre-frontal
daytime heating may become sufficient for thunderstorms capable of
producing damaging wind gusts, perhaps aided by modest deep-layer
shear near the leading edge of strengthening north-northwesterly
mid/upper flow.

...Southern Great Plains...
Potential for sustained convective development within a very warm
and deeply mixed boundary across the Texas Panhandle into western
Oklahoma late this afternoon remains uncertain. However, to the
east of the lee surface trough, warm advection and lift associated
with a nocturnal strengthening south-southwesterly low-level jet
will pose better potential for thunderstorm development across
northern/eastern Oklahoma tonight. It is possible that elevated
instability and unsaturated sub-cloud air may be sufficient to
contribute to potential for hail and gusty surface winds with some
of this activity.

...Northern Great Plains...
Models suggest that daytime heating may contribute to a deep mixed
boundary layer with modest CAPE, along and south of a developing
zone of stronger differential surface heating, southeast of the
Black Hills into central Nebraska. Aided by forcing for ascent
associated with a short wave digging around the northeastern
periphery of the building larger-scale ridging, isolated strong
thunderstorm development posing a risk for producing strong surface
gusts is possible for a period late this afternoon and evening.

$$

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ACUS01 KWNS 171948
SWODY1
SPC AC 171946

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0146 PM CST Sun Dec 17 2023

Valid 172000Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL
NORTH CAROLINA AND THE OUTER BANKS...

CORRECTED FOR TYPO

...SUMMARY...
Isolated damaging gusts and a couple of tornadoes will be possible
through tonight across coastal North Carolina and the Outer Banks.

...20z Update...

A damaging wind and tornado risk will continue into the evening
across the North Carolina coast and Outer Banks. A few stronger
cells interacting with the baroclinic zone along the coast have
shown rotation, with a possible tornado observed via radar earlier
this afternoon near the SC/NC border. While cloud cover, widespread precipitation and poor lapse rates will limit instability, strong
low-level vertical wind profiles will remain favorable for damaging
gusts and a couple of tornadoes. The only change with the 20z update
was to trim severe probabilities from most of South Carolina in the
wake of the surface low and primary surface trough. General thunder
was also removed on the western periphery of the outlook area,
mainly from GA and upstate SC.

..Leitman.. 12/17/2023

.PREV DISCUSSION... /ISSUED 1028 AM CST Sun Dec 17 2023/

...Discussion...
Recent surface analysis shows a low just off the northeastern Florida/southeastern Georgia coast at this time, which is progged to
steadily deepen while shifting north-northeastward through tonight.
At this time, what appears to be the most likely track for the low
will be to remain just off the South Carolina coast through the
daytime hours, and then possibly move just inland across coastal
North Carolina or the Outer Banks overnight.

North of the low track, widespread/steady precipitation is ongoing,
which should reinforce a persistent cool/stable boundary layer
inland through the daytime hours. With that said, the favorably
strong/veering wind field observed within the northeast quadrant of
the low continues to support occasionally rotating cells just
offshore. This will continue, along with gradually increasing
potential that a couple of these cells will begin moving inland
across South Carolina coastal counties northeast of Charleston.
While any storms would become increasingly elevated along their
inland advance, storms may remain rooted near enough to the surface
across immediate coastal counties of northeastern South Carolina --
and then later over eastern North Carolina and in particular the
Outer Banks -- to yield risk for a couple of tornadoes, and possibly
locally damaging wind gusts. As such, will maintain current
delineation of the SLGT risk area just inland across South Carolina
for today, and then across eastern North Carolina and the Outer
Banks area for this evening and overnight.

$$

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ACUS01 KWNS 130056
SWODY1
SPC AC 130055

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0655 PM CST Mon Feb 12 2024

Valid 130100Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
TN/NORTHEAST GA THROUGH THE CAROLINAS...

CORRECTED FOR INCORRECT DAY REFERENCE IN TEXT

...SUMMARY...
Isolated wind damage and a tornado or two will be possible,
primarily across the coastal Carolinas overnight.

...01Z Update...

...Eastern TN/Northeast GA through the Carolinas...
A strongly forced, shallow convective line continues to push
eastward across eastern TN and western GA, forced by strong ascent
attendant to the eastward-moving shortwave currently over the
Mid-South. This line is forecast to continue eastward this evening
and overnight, moving across Carolinas and offshore by early
Tuesday. Buoyancy ahead of the line will remain limited, but a few
convectively augmented gusts are still possible across this region
this evening and overnight

Current surface observation place the 60 deg F dewpoints over
southern GA. There is some potential for this better low-level
moisture to advect northward into the coastal portions of the
Carolinas, augmented by some advection off the Atlantic as well.
This could help foster modest buoyancy ahead of the approaching
convective line, contributing to a greater chance for deeper
updrafts and near-surface-based storms capable of a few damaging
gusts and maybe even a brief tornado.

..Mosier.. 02/13/2024

$$

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ACUS01 KWNS 221419
SWODY1
SPC AC 221418

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0818 AM CST Thu Feb 22 2024

Valid 221300Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE MID-SOUTH REGION...

CORRECTED FOR TYPO

...SUMMARY...
Thunderstorms may produce marginally severe gusts or hail this
afternoon and evening over parts of the Mid-South region.

...Synopsis...
In the mean, mid/upper-level pattern amplification should begin
again during this period, as ridging builds over NV, the Pacific
Coast States and interior Northwest. Downstream, a series of
shortwaves will contribute to substantial synoptic-scale height
falls over much of the Mississippi and Ohio Valleys to the central
Gulf Coast. None of those perturbations -- including some apparent
in moisture-channel imagery over OK, northern KS/NE, and western CO
-- are (or will become) particularly intense, but should contribute
to at least weak large-scale destabilization aloft and maintenance
or strengthening of cyclonic flow.

At the surface, 11Z analysis showed a cold front extending from a
low over southeastern ON across northern IN, through weak lows over
central MO and near TUL, then across northwest TX to southern NM.
The front should move eastward and southeastward today, to a 00Z
position over eastern/southern OH, the lowest Ohio Valley, eastern/
southern AR, and northeast to south-central TX. By 12Z, the front
should reach central NY, eastern PA, the southern Appalachians,
central parts of MS/LA, and shelf waters of the northwestern Gulf.

...Mid-South region...
Isolated to widely scattered thunderstorms are expected to develop
by late this afternoon along/ahead of the cold front, over central/
eastern AR and perhaps western TN. Activity should strengthen and
increase in coverage through evening as it encounters greater
moisture across the Mississippi Valley and into northern portions of
MS tonight. Some upscale organization into a short QLCS is possible
from early multicell to supercell modes. Marginally severe hail and
damaging gusts will be the main concerns.

The outlook area will reside on the southwestern rim of a far larger
swath of general thunderstorm potential, but with access to
sustained, effectively surface-based and at least marginally moist
inflow parcels beginning mid/late afternoon in AR and shifting east- southeastward with time. Progs that generate little substantial
convection generally are too cool at the surface. Forecast max
surface temperatures in the mid/upper 60s F over much of the area
will support favorable low-level lapse rates, as well as some
boundary-layer mixing, amidst potential for localized downward
momentum transfer from stronger flow aloft, for gust support.

Midlevel lapse rates are not expected to be very strong, limiting
MLCAPE to around 250-750 J/kg, and likely keeping the hail potential
isolated, marginal and conditional to supercell maturation.
Sufficient deep shear will exist for that, however, with modified
forecast soundings indicating around 40-45-kt effective-shear
magnitudes and 150-250 J/kg effective SRH -- despite prefrontal
veering with time of surface winds toward southwesterly. Greater
diurnal boundary-layer mixing/drying, EML-related CINH and weaker
CAPE will likely restrict severe potential around western parts of
the outlook, while instability decreases northward, moisture
decreases eastward, and lift weakens southward.

..Edwards.. 02/22/2024

$$

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ACUS01 KWNS 030557
SWODY1
SPC AC 030555

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1155 PM CST Sat Mar 02 2024

Valid 031200Z - 041200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
FLORIDA PENINSULA...

CORRECTED FOR THUNDER LINES

...SUMMARY...
A few strong thunderstorms will be possible across parts of Florida
during the afternoon and early evening. Isolated hail is expected to
be the primary threat, though locally gusty winds may also occur.

...Synopsis...
A deep upper-level trough will persist over the western CONUS
through the period, as a strong embedded shortwave moves from the
central High Plains toward the upper Great Lakes region. A surface
low attendant to this shortwave will move northward across the
Dakotas and Minnesota, with secondary cyclogenesis expected over the
central High Plains during the afternoon/evening. Farther east, a
weak upper-level trough will move slowly eastward across parts of
the Southeast, to the south of a building upper ridge across the Mid Atlantic/Northeast.

...Florida...
Moderate buoyancy (MLCAPE of 1000-1500 J/kg) will likely develop
during the afternoon across much of the FL Peninsula, resulting from
seasonably strong diurnal heating of a relatively moist low-level
environment. Diminishing MLCINH will support scattered thunderstorm development, especially in association with sea-breeze circulations
and possibly near any other boundaries left over from
overnight/early-morning convection.

Very weak low-level flow and only modest deep-layer flow/shear will
tend to limit storm organization and longevity, but storm
interactions and locally enhanced shear near the sea breezes could
yield a couple stronger multicells and perhaps a marginal supercell.
With relatively cold temperatures aloft (-13C to -16C at 500 mb)
associated with the upper trough, the strongest storms could pose an
isolated hail threat. Locally gusty winds will also be possible,
though the severe-wind threat appears relatively limited due to very
weak low-level flow and limited potential for organized upscale
growth.

..Dean/Weinman.. 03/03/2024

$$

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ACUS01 KWNS 042204
SWODY1
SPC AC 042203

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0403 PM CST Mon Mar 04 2024

Valid 042000Z - 051200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A LARGE
AREA FROM CENTRAL/EAST TEXAS INTO MOST OF THE MISSISSIPPI VALLEY...

CORRECTED FOR TYPO

...SUMMARY...
Isolated strong to severe thunderstorms will be possible this
afternoon into tonight from parts of central Texas into the lower
Mississippi Valley, as well as from the Ozarks into the Midwest.
Large hail is expected to be the main threat, but strong/gusty winds
and even a tornado may also occur.

...20Z Update...

...Eastern IA/Northern MO/Northern IL...
Recent surface analysis places a low just south of the IL/WI/IA
border intersection. A cold front extends southwestward from this
low across northern MO and eastern KS, while a warm front extends
eastward across northern IL and then arcs sharply northeastward over
southern Lake Michigan. A few elevated storms have been noted near
the surface low, with some deepening warm sector cumulus also
ongoing from central MO into northern/central IL. As mentioned in
MCD #0189, additional thunderstorm development is still expected
along and just ahead of cold front from far eastern IA into
northwest Illinois and northeast Missouri in the next 1-3 hours.
Front-parallel orientation to the deep-layer vertical shear will
likely lead to an undercutting of these storms, with a predominantly
elevated storm mode anticipated. Even so, steep lapse rates will
support some stronger updrafts capable of hail. Some damaging gusts
are possible as well, particularly as cells interact with the cold
front.

...East TX/LA/Western MS this afternoon and evening...
Scattered thunderstorms are currently ongoing from East TX across
much of LA, supported by southwesterly flow aloft and resultant
warm-air advection. General expectation is for these storms to
gradually shift northeastward into more of western MS over time, in
tandem with the zone of most favorable warm-air advection. Modest
vertical shear remains favorable for transient supercell structures
and the threat for hail and damaging gusts.

...Eastern OK into Mid MS Valley this evening and overnight...
Thunderstorm development along the front later this evening along
the from southern MO into eastern OK remains uncertain, given the
potential for warm mid-level temperatures and resulting capping.
Additionally, vertical shear will be modest, with a resultant
potential for the front to undercutting development. Even so, the
warm and moist low-levels combined with steep mid-level lapse rates
will support a conditional risk for severe hail.

..Mosier.. 03/04/2024

.PREV DISCUSSION... /ISSUED 1000 AM CST Mon Mar 04 2024/

...East TX/LA/Western MS Today...
Moderately strong southern-stream mid-level flow is present today
across the southern states, with several weak perturbations
affecting the area. A warm and moist surface air mass is in place
across east TX into LA, where dewpoints in the upper 60s and 70s
will yield afternoon MLCAPE of 1500-2000 J/kg. Weak low-level warm
advection is expected to result in increasing thunderstorm
development this morning through the afternoon as storms spread
eastward toward southwest MS. Deep-layer shear is sufficient for at
least transient supercell structures, but relatively weak low-level
winds suggest the main threats will be hail and gusty winds with the
strongest cells.

...Eastern IA/Northern MO/Northern IL...
A strong surface cold front is sagging southeastward across IA this
morning into a marginally moist and unstable air mass. All 12z
model guidance agrees on the development of showers and
thunderstorms along the front by early afternoon, although many
solutions suggest most of the activity will be behind the front and
slightly elevated. Nevertheless, cool temperatures aloft and steep
mid-level lapse rates will promote hail in the stronger cores.
Storms that can form and persist ahead of the front would have some
marginal concern for gusty winds and perhaps a brief tornado as
well.

...Eastern OK into Mid MS Valley...
Morning model guidance is quite diverse in the development of
thunderstorms across this region, with low confidence in any
particular area. Will maintain the ongoing MRGL area as a
conditional risk if storms can form - mainly due to unseasonably
warm and moist conditions and sufficient CAPE for some risk of hail.
However, considerably uncertainty exists.

$$

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ACUS01 KWNS 071721
SWODY1
SPC AC 071720

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1120 AM CST Thu Mar 07 2024

Valid 071630Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS...

CORRECTED FOR WEB GRAPHICS ERRORS

...SUMMARY...
Severe thunderstorms are possible over parts of the southern Plains
this afternoon into tonight.

...Synopsis...
An upper trough is deepening across the Four Corners region today,
with fast mid/high level flow extending across northern Mexico into
TX. Beneath this fast zonal flow regime, southerly low-level winds
are helping to advect/maintain upper 50s and 60s dewpoints over much
of TX and southern OK. Widespread cloud cover this morning will
continue to suppress strong heating except across western OK and
west-central TX where a dryline will develop. This will lead to
multiple mesoscale areas of concern for strong/severe thunderstorm
development this afternoon and evening.

...Central TX...
An area of residual precipitation is affecting north-central TX.
The outflow boundary along the southern edge of this convection will
likely become the focus for intensifying storms later today. Strong
flow aloft will promote supercell structures, with very large hail
possible in the initial activity. Storms that can maintain discrete
nature may also pose some tornado risk this evening as southerly
low-level winds and shear increase. By late evening, remaining
storms may track eastward across the SLGT risk area with a threat of
damaging wind gusts.

...Western/Central OK...
Isolated supercell storms are expected to form along the diffuse
dryline over western OK and western north TX. This activity may
produce very large hail initially, but an evolution to more linear
structures is expected during the early evening, with hail and
damaging winds possible.

...Southeast KS/Southwest MO...
Dense cloud cover over this region is expected to erode by mid
afternoon, allowing some daytime heating and destabilization along a
surface boundary extending across eastern KS into western MO. This
zone will likely be the focus for scattered afternoon thunderstorms.
Despite rather weak instability, shear profiles would support
supercell structures capable of all severe hazards for several hours
through early evening.

..Hart.. 03/07/2024

$$

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ACUS01 KWNS 121645
SWODY1
SPC AC 121643

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1143 AM CDT Fri Apr 12 2024

Valid 121630Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF EASTERN NEW YORK/WESTERN NEW ENGLAND...AND FROM NORTHERN NEVADA
TO WESTERN MONTANA...

CORRECTED TO REMOVE LESS THAN 2% TORNADO TEXT FROM THE PROBABILITY
GRAPHIC

...SUMMARY...
Isolated severe wind gusts and hail may occur with thunderstorms
over northern Nevada, eastern Oregon, Idaho, and far western Montana
late this afternoon and early evening.

...Champlain/Hudson Valleys of New York into western New England...
Showers appear to be increasing at this time across the
Hudson/Champlain Valleys, ahead of an occluded front moving eastward
across eastern portions of Upstate New York early this afternoon. A
lobe of vorticity will continue rotating northeastward across the
region this afternoon, on the eastern fringe of the upper low
crossing the Great Lakes. Cold air aloft combined with weak
insolation through breaks in the cloud cover evident in visible
satellite imagery will permit additional/modest destabilization. As
a result, low-topped thunderstorms are expected to develop across
this area.

With deep-layer flow somewhat unidirectional/meridional, but
strengthening with height, shear will support organized storms and
potentially a few rotating updrafts. As a result, a brief/weak
tornado or two will be possible, along with gusty winds that may
approach severe levels locally, with a few stronger cells and/or
line segments. As such, a MRGL risk is being introduced across a
portion of eastern New York and into parts of western New England.
For additional short-term information, please refer to SWOMCD #429.

...Parts of northern Nevada to western Montana...
Ahead of the advancing upper low, daytime heating beneath steep
mid-level lapse rates will result in modest destabilization, with
degree of CAPE hindered due to scant moisture availability across
this region. Still, with a few hundred J/kg mixed-layer CAPE likely
by late afternoon, widely scattered thunderstorms are expected to
develop.

With favorably strong flow aloft across this area, a few
stronger/sustained updrafts appear likely. With a very deep
well-mixed boundary layer expected across the region, gusty
downdraft winds -- enhanced due to evaporative cooling in the
sub-cloud layer -- may reach severe levels in a few instances. This
warrants continuation of the MRGL risk across into early evening.

...Ohio Valley to the Mid-Atlantic region...
Scattered showers should diurnally increase from parts of the OH
Valley across the central Appalachians to the Virginia/North
Carolina area, with eventual/embedded low-topped thunderstorms
expected to develop within the broader area of precipitation this
afternoon.

The convection will be associated with cold mid-level temperatures
accompanying a shortwave trough, that is embedded within the broader
cyclonic circulation across the eastern CONUS. With generally west-northwesterly flow behind the cold front, instability should
remain very weak. Still, enhanced low-level winds may reach the
surface given the anticipated well-mixed boundary layer, resulting
in occasional strong/gusty winds with a few of the stronger
convective elements.

..Goss/Bentley.. 04/12/2024

$$

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ACUS01 KWNS 261644
SWODY1
SPC AC 261642

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1142 AM CDT Fri Apr 26 2024

Valid 261630Z - 271200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING FROM EASTERN NEBRASKA/WESTERN IOWA SOUTHWARD TO EASTERN
OKLAHOMA AND NORTHEAST TEXAS...

CORRECTED FOR WEB GRAPHICS ERROR

...SUMMARY...
A few tornadoes, including a couple of strong tornadoes, isolated
very large hail (greater than 2 inch diameter) and isolated wind
damage will be possible, mainly this afternoon/evening from
northeast Kansas/southeast Nebraska into western Missouri, eastern
Oklahoma, western Arkansas, and northeast Texas.

...NE/IA/MO/KS...
Water vapor loop shows a strong shortwave trough rotating across
KS/NE. A deep surface low is analyzed ahead of this trough over
central NE, with a dryline extending southward into central KS. A
corridor of ample low-level moisture is present ahead of the dryline
over southeast NE/northeast KS, where daytime heating will lead to
moderate MLCAPE values and rapid thunderstorm development by
mid-afternoon. Backed low-level winds and favorable shear profiles
will promote supercells in the bent-back region of the low, with
very large hail and tornadoes possible. These storms will progress
eastward into western IA and northwest MO through the early evening.
A strong tornado or two is possible in this region.

...OK/MO/AR...
A large nocturnal MCS that affected much of OK has quickly weakened
and departed, with rapid northward return of low-level moisture
occurring in the wake of the system. By mid-afternoon, mid-upper
60s dewpoints are expected along the dryline over east-central OK.
Forecast soundings show very steep mid-level lapse rates and
favorable shear profiles to promote discrete supercells capable of
all severe hazards, including very large hail and strong tornadoes.
Storms will track northeastward into southwest MO and northwest AR
this evening. CAM guidance varies on coverage of storms, but
parameters appear quite strong and warrant an upgrade to ENH given
the conditional risk of significant severe weather.

...Northeast TX...
A third area of significant risk of severe storms lies across parts
of northeast and east-central TX today. A cluster of
severe/supercell storms has formed this morning to the west of Waco,
TX. These storms are expected to increase in coverage through the
afternoon and develop eastward across much of northeast TX.
Forecast soundings show a very moist and unstable environment, with
sufficient low-level and deep-layer shear for persistent supercell
structures and risks of a few tornadoes and very large hail. Given
the number of storms and the favorable environment, have also
upgraded this narrow corridor to ENH.

..Hart.. 04/26/2024

$$

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ACUS01 KWNS 270754
SWODY1
SPC AC 270753

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0253 AM CDT Sat Apr 27 2024

Valid 271200Z - 281200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH TEXAS...OKLAHOMA...SOUTHEAST KANSAS AND FAR SOUTHWEST
MISSOURI...

CORRECTED FOR GEOGRAPHIC REFERENCE IN MISSOURI

...SUMMARY...
Numerous severe thunderstorms are likely today and tonight across
the southern and central Plains into the lower to mid Missouri
Valley. The greatest potential for severe storms will be from north
Texas into Oklahoma and southeast Kansas, where strong tornadoes,
very large hail over 2 inches in diameter and widespread damaging
winds (some over 70 mph), are expected to occur. A broader area of
severe threat will extend from south-central Texas
north-northeastward to the Great Lakes.

...Tornado Outbreak Expected Today From North Texas into
Oklahoma...Southeast Kansas and Far Southwest Missouri...

...Southern Plains...
An upper-level trough will move through the Desert Southwest today
as an 80 to 90 knot mid-level jet translates quickly eastward
through the base of the system. Ahead of the trough, a moist and
unstable airmass will be in place across much of the southern and
central Plains. At the surface, a low will move eastward across
southwest Kansas with a dryline extending southward through far
western Oklahoma and west Texas. Surface dewpoints to the east of
the dryline will be in the mid to upper 60s F. In response to warm
advection this morning, a cluster of thunderstorms is expected to
develop to the east of the dryline across northwest Texas. This
cluster is forecast to spread north-northeastward into western
Oklahoma by late morning. Large hail and wind damage will be likely
with the stronger cells within this cluster. An outflow boundary
with this convection should setup across west-central Oklahoma by
early afternoon, with a moist and unstable airmass extending
eastward from the boundary across much of central and eastern
Oklahoma northward into southeast Kansas. This undisturbed airmass
is expected to be favored for the greatest severe threat this
afternoon and evening.

The mid-level jet is forecast to eject quickly northeastward across
the southern Plains this afternoon. This will result in strong
deep-layer shear across most of the southern Plains, and will create
a large-scale mass response that will be very favorable for severe
storms, including supercells and bowing line segments. As the core
of the mid-level jet moves into the southern Plains during the mid
to late afternoon, a 50 to 60 knot low-level jet will rapidly
strengthen. RAP forecast sounding along and near the low-level jet
during the late afternoon look very favorable for tornadoes, with
backed surface flow, and long looping hodographs. As the low-level
jet strengthens, 0-3 km storm-relative helicity is forecast to
increase to around 400 m2/s2 across much of central and eastern
Oklahoma into southwest Missouri. The more dominant and supercells
that interact with the western and northern edge of the low-level
jet are expected to become tornadic. Several strong tornadoes will
be likely, and a few long-track EF3+ tornadoes will be possible.

In addition to the tornado threat, forecast soundings have 700-500
mb lapse rates near 8 C/km across much of the warm sector this
afternoon from north Texas to southeast Kansas. This will be
favorable for very large hail, with hailstones over 2 inches in
diameter likely with the more intense storms. Later in the evening,
a line of severe storms is expected to form, moving eastward across
eastern Oklahoma and north Texas. Wind gusts over 70 mph will be
possible with the more intense parts of the line. QLCS tornadoes
will also be possible with rotating cells embedded in the line late
this evening into the overnight period.

...Central Plains/Lower to Mid Missouri Valley...
An upper-level low will move through the southern Rockies today, as
the exit region of a mid-level jet overspreads the central Plains.
At the surface, a warm front will be located from near a surface low
in southwest Kansas east-northeastward into the mid Missouri Valley.
This front will be a focus for convective development this
afternoon. A band of severe storms is expected to form near the
front and move northward across northern Kansas into southern
Nebraska during the early to mid afternoon. RAP forecast soundings
in northeast Kansas near the front from 18Z to 21Z have MLCAPE near
3000 J/kg, 0-6 km shear around 60 knots, and steep low to mid-level
lapse rates. This environment will be very favorable for supercells
with large hail. Hailstones greater than 2 inches in diameter will
be possible with the more intense storms. In addition, forecast
soundings have 0-3 km storm-relative helicity in the 250 to 300
m2/s2 range, suggesting that tornadoes will be likely with the more
discrete supercells. A few strong tornadoes will be possible.

Further west into northwest Kansas and eastern Colorado, cold
temperatures aloft, strong large-scale ascent associated with an
upper-level low, and strong deep-layer shear will likely support
lower-topped supercells with large hail and strong wind gusts this
afternoon.

...Mid to Upper Mississippi Valley/Great Lakes...
An upper-level trough will move northeastward across the Great Lakes
region today. From near the trough, and southwestward into the mid
to upper Mississippi Valley, a wide corridor of moderate instability
will be in place by afternoon. A warm front will be in located along
the northern edge of the instability, from Iowa northeastward into south-central Wisconsin and north-central lower Michigan. As surface
heating takes place and low-level convergence increases along the
front, thunderstorms will likely form in the vicinity of the
boundary. Forecast soundings near the front at 21Z have MLCAPE
around 3000 J/kg, along with 40 knots of deep-layer shear. This
should support supercells with potential for large hail and wind
damage. The severe threat should be greatest during the late
afternoon and early evening.

..Broyles/Thornton.. 04/27/2024

$$

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ACUS01 KWNS 022007
SWODY1
SPC AC 022005

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0305 PM CDT Thu May 02 2024

Valid 022000Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
NORTHWEST TX...

CORRECTED FOR WIND PROBABILITY LINE IN LOUISIANA

...SUMMARY...
Strong to severe thunderstorms will be possible late this afternoon
into tonight from parts of the Upper Midwest to the southern Plains.
The greatest potential appears to be over parts of northwest into
central Texas.

...20Z Update...
The primary change at 20Z is to remove the Marginal Risk from parts
of southeast TX, in the wake of a weakening MCS near the LA Gulf
Coast. Some additional development remains possible into southeast
LA within a warm and very moist environment, but any remaining
severe threat is expected to be isolated.

Otherwise, no major changes have been made to the categorical areas.
The 2% tornado area has been extended northeastward through MO into
IL, given the presence of discrete convection within this corridor
and an earlier tornado report near Joplin.

Isolated to widely scattered supercell development is still expected
near the northwest TX vicinity, with a threat of very large hail and
possibly a tornado or two. See the previous discussion below for
more information, and MCD 604 and MCD 605 for more information
regarding the short-term threats from TX into the MS Valley.

..Dean.. 05/02/2024

.PREV DISCUSSION... /ISSUED 1105 AM CDT Thu May 02 2024/

...TX...
Morning surface analysis shows a cold front sagging southward across
the TX Panhandle and northwest OK, with a dryline extending
southward across west TX. Ample low-level moisture is present to
the east of the dryline, where a combination of strong afternoon
heating and very steep mid-level lapse rates will yield MLCAPE
values around 4000 J/kg. Deep layer flow is not particularly
strong, but given the impressive thermodynamic environment, the
setup should support scattered slow-moving supercells capable of
very large hail and damaging winds. Have upped hail probabilities
in parts of this region. The cluster of storms may grow upscale
after dark, building southeastward into central TX.

...OK into Western Great Lakes...
A cold front extends from northwest OK into IA. A large shield of
prefrontal precipitation is affecting parts of northern MO and
eastern IA. Along and south of the front/cloud shield, areas of
strong heating will occur this afternoon. Most CAM solutions
suggest multiple clusters of thunderstorms will form in this
differential heating zone, with a risk of a few strong/severe cells
capable of gusty/damaging winds and hail. Confidence in a more
organized severe threat is not sufficient to add a SLGT risk at this
time.

$$

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