ACUS02 KWNS 140556
SWODY2
SPC AC 140555

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Sun Apr 14 2024

Valid 151200Z - 161200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN WESTERN OK
AND A PART OF NORTHWEST TX...

...SUMMARY...
Scattered severe thunderstorms are likely across the southern to
central Great Plains, mainly Monday evening and night. Large to very
large hail, damaging wind gusts, and a few tornadic storms are
possible.

...Central/southern Great Plains...
A shortwave trough will be centered on the southeast Great Basin at
12Z Monday. Multiple embedded impulses will eject east across the
southern Rockies and Southwest, and onto the central to southern
High Plains by early morning Tuesday. This fragmented evolution and
timing of ejection onto the southern High Plains appears ill-timed
with the peak diurnal heating cycle. The southern/more vigorous of
the impulses will yield substantial tropospheric flow amplification
as a mid-level jetlet in excess of 80 kts at 500 mb evolves across
the southern TX Panhandle into south KS Monday night.

Substantial lee cyclogenesis will occur over the central High Plains
by Monday afternoon, and drift east along the KS/NE border through
12Z Tuesday. Low-level moisture modification from the northwest
Gulf, while sufficient for severe storms, will not be overly rich or
deep beneath a stout elevated mixed layer. Mid 60s surface dew
points should become common over the southern Great Plains ahead of
the dryline by evening with low 60s to upper 50s with northern
extent in the central Great Plains.

Late afternoon to early evening thunderstorm development will
probably be bimodal, with more probable convection across the
central High Plains arcing east-southeast along the surface warm
front into the Mid-MO Valley. Boundary-layer moisture will be less
with northwest extent, but favorable deep-layer ascent within a
meridional to backed wind profile should be conducive to large hail
and isolated severe wind gusts. Along the warm front into the Mid-MO
Valley, most development should remain on the cool side of the
surface warm front amid northeast storm motions, but there will be
the possibility of a few surface-based supercells with a
tornado/wind threat in addition to large hail.

A separate corridor of a few storms should form in west TX along the
dryline within the deeply mixed air owing to a stout capping
inversion across the warm-moist sector where mid/upper-level
cloudiness should temper insolation. Mid-level height falls and
tropospheric flow fields will increase into Monday night. 00Z NCEP
guidance outside of the GFS suggest minimal to isolated convective
coverage should be expected until near the end of the period, while
the ECMWF remains consistent with earlier runs depicting
substantially greater convective development overnight. While this
lowers confidence in the degree of supercell coverage amid robust
MLCIN with southeast extent in OK/TX, have maintained level 3-ENH
risk where the conditional threat for strong supercells is greatest.

...VA/NC...
A weakening surface cold front should sag south in VA on Monday,
with a ribbon of modest boundary-layer moisture along it. Strong
insolation will occur ahead of it into NC, yielding a deeply mixed
boundary layer. Low-level convergence should be sufficient for
isolated to scattered thunderstorm development by late afternoon.
Moderate mid-level flow will be present and increase in height
within the peripheral influence of a strong jet across parts of the
Great Lakes into southern New England. Amid steep mid-level lapse
rates, overall setup should support a few multicells capable of
marginally severe hail initially, and strong to marginally severe
wind gusts as storms spread southeast before weakening after dusk.

..Grams.. 04/14/2024

$$
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ACUS02 KWNS 241732
SWODY2
SPC AC 241730

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Wed Apr 24 2024

Valid 251200Z - 261200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM WESTERN
KANSAS SOUTHWARD THROUGH THE EASTERN TEXAS PANHANDLE/WESTERN
OKLAHOMA INTO NORTHWEST TEXAS...

...SUMMARY...
Scattered severe thunderstorms are expected from late Thursday
afternoon into Thursday night across parts of the central and
southern Great Plains. Very large hail, severe wind gusts, and a
couple strong tornadoes will all be possible.

...Synopsis...
A shortwave trough is forecast to begin the day extended from
central NV into far northwest Mexico before then quickly moving
eastward across the Southwest and into the southern/central High
Plains, becoming increasingly negatively tilted with time. Strong
mid-level flow will accompany this shortwave, spreading
eastward/northeastward into the central and southern Plains ahead of
the parent shortwave.

At the surface, cyclogenesis is anticipated ahead of the shortwave
trough across the central High Plains, with the resulting low then
gradually moving northeastward from eastern CO into western
KS/southwest NE late Thursday night/early Friday morning. A
sharpening dryline will extend southward from this low throughout
most of the period. A warm front will extend east-southeastward
from this low as well, extending into northeast OK Thursday morning.
This warm front is forecast to move northward throughout the day,
moving through much of KS by early Friday morning. A moist and
buoyant warm sector will exist south of this front, and strong to
severe thunderstorms are anticipated the shortwave interacts with
it.

...Southern/Central Plains...
Numerous showers and thunderstorms will likely be ongoing Thursday
morning from north-central/eastern KS into western MO and
northeastern OK, supported by strong warm-air advection across the
warm front. Given that at least moderately low-level southerly flow
is expected to persist throughout the period, expectation is that
this activity will persist as well, while perhaps gradually shifting southeastward with time. Overall buoyancy and vertical shear will be
modest, but a few stronger cores capable isolated hail are possible.
Overall evolution of this early morning activity could lead to
either a sharpening of the warm front from the central KS vicinity southeastward through northeast OK into western AR or potentially southward/southwestward slow-moving outflow boundary. This sharp
boundary is expected to limit to eastern/northeastern extent of the
greater severe potential.

Farther west, persistent moisture advection is anticipated amid
moderate low-level southerly flow ahead of the approaching shortwave
trough. This is expected to result in mid 60s dewpoints by the
mid-afternoon across much of the eastern TX/OK Panhandle and OK,
with low 60s dewpoints reaching into south-central KS. Mid 60s
dewpoints are expected into western and south-central KS by early
evening. Steep mid-level lapse rates will exist a top this low-level
moisture, supporting moderate to strong buoyancy, with the
strengthening mid-level flow supporting robust deep-layer vertical
shear as well.

Some capping is anticipated along the dryline, but the combination
of strong diurnal heating (in the wake of morning clouds),
increasing large-scale ascent, and low-level convergence is expected
to result in convective initiation during the late afternoon. Widely
scattered to scattered thunderstorm coverage appears probable, with
storms quickly becoming severe after initiation. Large to very large
hail will be the primary threat with the initial development. The
tornado threat will also increase with any supercell that persists
into the evening, with low-level shear/SRH expected to increase with
time and eastward extent. As such any longer-lived supercells could
pose a strong tornado threat, particularly across
west-central/southwest KS where surface flow will be backed given
closer proximity of the surface low.

Additional thunderstorms are anticipated farther south Thursday
night as the Pacific front surges eastward. Highest storm coverage
currently appears most likely from southwest OK into northwest TX.
Initial development could produce large to very large hail before
then transitioning to a more linear mode. Some downstream severe
threat into north-central TX and south-central/central OK appears
likely, although uncertainty remains regarding overall intensity,
largely as a result of low-level nocturnal stability. However,
kinematic fields are quite strong and could maintain organized storm
structures capable of all severe hazards eastward into north-central
TX and south-central/central OK. This area will be assessed for
increased severe probabilities in later outlooks.

...Central High Plains into Nebraska...
Numerous thunderstorms are expected to develop from northeast CO/NE
Panhandle northeastward into NE Thursday night as large-scale ascent
spreads across the region. Most of this activity will be elevated,
but the presence of steep mid-level lapse rates and moderate
vertical shear suggests large hail is possible with these storms,
with perhaps even some very large hail (i.e. 2 to 2.5" in diameter)
in the CO/NE/KS border vicinity where surface-based parcels are
possible.

...Eastern WY into Southwest SD...
Moderate buoyancy will support scattered diurnal thunderstorm
development into the Black Hills vicinity. Deep-layer shear will be
weaker in this area than areas farther south, but may still be
sufficient for modestly organized storms capable of large hail.

..Mosier.. 04/24/2024

$$
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ACUS02 KWNS 250602
SWODY2
SPC AC 250600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu Apr 25 2024

Valid 261200Z - 271200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
EASTERN NE...NORTHEAST KS...WESTERN IA...NORTHWEST MO...

...SUMMARY...
An active severe weather day appears possible on Friday from parts
of Nebraska and Iowa southward into parts of the southern Great
Plains and Ozarks. A few tornadoes (possibly strong), large to very
large hail, and damaging winds will all be possible.

...Synopsis...
A negatively tilted mid/upper-level shortwave trough and attendant
surface low are forecast to move northeastward toward the upper
Great Lakes from Friday into Friday night. A trailing Pacific
front/dryline will move eastward through the day across the
central/southern Plains, before retreating westward Friday night. A
warm front will move northward in advance of the surface low across
MO into parts of IA. Farther west, another deep mid/upper-level
trough will move eastward across the Southwest into the southern
Rockies.

...Eastern NE/KS into western IA/MO...
Supercells capable of all severe hazards appear possible from
eastern NE/KS into western IA/MO, though coverage of the threat with
southward extent somewhat uncertain at this time.

In the wake of morning convection, at least a narrow zone of
moderate destabilization will be possible from parts of eastern NE
into western IA, between the northward-moving warm front and
approaching Pacific front/dryline. Scattered thunderstorm
development is expected during the afternoon, with favorably veering
low-level wind profiles and moderate deep-layer shear supporting
supercell potential. Steep midlevel lapse rates will support a hail
threat, with some potential for very large hail depending on the
magnitude of destabilization. A few tornadoes will also be possible,
both in the vicinity of the surface low, and with any longer-lived
supercells along the dryline into southeast NE/southwest IA.

Farther south, a broader and potentially more unstable warm sector
is expected to evolve across eastern KS into western MO. While
large-scale ascent will be weaker with southward extent, at least
isolated supercell development will be possible along the dryline by
late afternoon. Any sustained supercells within this regime would
pose a threat for tornadoes and very large hail. A strong tornado or
will be possible if stronger pre-convective destabilization can
materialize.

...Eastern OK/northeast TX into AR/southern MO...
Initially strong storm clusters are expected to move across eastern
OK and potentially northeast TX into AR and MO through the morning,
accompanied by at least an isolated hail and damaging gust threat.
Some of this convection may persist or tend to regenerate along the
eastern periphery of the primary instability axis. The eastern
extent of any severe threat remains uncertain, but favorable
low-level and deep-layer shear could support occasionally organized
convection, with an isolated/marginal threat for all severe hazards.

Farther west, moderate to strong instability and deep-layer shear
will support a conditionally favorable environment along the dryline
from eastern OK into northeast TX. In the wake of the departing
shortwave trough, development along the dryline in this area will
likely be very isolated, though any sustained cells would pose a
threat for very large hail and possibly a tornado.

...Edwards Plateau into the Permian Basin vicinity of TX...
As the dryline retreats late Friday night, convection could develop
prior to the end of the period into parts of southwest TX, in
advance of the approaching southwestern trough. Instability and
shear would be sufficient for organized convection, though timing
and coverage of any threat in this area remain too uncertain at this
time for probabilities.

..Dean.. 04/25/2024

$$
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ACUS02 KWNS 240537
SWODY2
SPC AC 240536

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1236 AM CDT Fri May 24 2024

Valid 251200Z - 261200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SATURDAY
EVENING THROUGH SATURDAY NIGHT ACROSS PARTS OF NORTHWESTERN
OKLAHOMA...CENTRAL AND EASTERN KANSAS INTO WESTERN MISSOURI...

...SUMMARY...
Severe thunderstorm development appears likely across parts of the
central and southern Great Plains by Saturday evening. This
probably will include a few supercells initially, before storms
gradually evolve into an organizing cluster overnight, accompanied
by a risk for large hail, a few tornadoes and severe wind gusts
across parts of Kansas and Oklahoma into western Missouri.

...Synopsis...
The most prominent mid-level short wave perturbations have mostly
become confined to the northern mid-latitudes. This includes one
forecast to dig southeast of the Canadian Maritimes and northern New
England coast, another pivoting northeast and east of the Great
Lakes region, and a third digging along/southeast of the western
Canadian/U.S. border area. However, models indicate that
subtropical ridging, centered over central Mexico and the
southwestern Gulf of Mexico, will remain suppressed, with several lower-amplitude waves progressing around its periphery. This will
include mid-level troughing likely to progress east of the south
Atlantic Seaboard, and another perturbation accelerating out of the
Southwest trailed by a similar strength perturbation accelerating
east of the Great Basin.

It appears that the latter two impulses will contribute to
larger-scale troughing progressing across the lower Missouri Valley
and central Great Plains by 12Z Sunday, accompanied by a deepening
surface cyclone emerging from the lee of the Colorado Rockies. In
the wake of a preceding cold front associated with the Great Lakes perturbation, which appears likely to stall southeast of the lower
Great Lakes through the Ohio Valley, rapid low-level moisture return
is forecast through the developing warm sector across the southern
through much of central Great Plains by late Saturday evening. It
appears this will reach much of the lower Missouri Valley by late
Saturday night. Beneath a plume of warm and capping elevated
mixed-layer air overspreading much of the central/southern Great
Plains and lower Mississippi Valley, models suggest that the
seasonably moist air will support large CAPE on the order of
2000-4000 J/kg.

...Great Plains...
While the general synoptic evolution appears fairly certain, there
is notable spread within/among the various model output concerning
the details, and smaller-scale evolution. With low-level moisture
return ongoing from the southeastern Great Plains during day, model
output indicating later timing (probably after 26/00z) of the more
appreciable increase in thunderstorm initiation seems likely to
verify best.

By early Saturday evening, it appears that the deeper boundary-layer
moistening may become focused in a narrow corridor across
northwestern Oklahoma into central Kansas, along/west of a
strengthening southerly 850 mb jet (in excess of 50 kt by late
evening). This may become the focus for the most intense potential
supercell development, posing a risk for large, damaging hail and
perhaps a strong tornado or two. This activity will tend to develop northeastward and eastward within the warm sector through mid to
late evening, before forcing associated with lower/mid-tropospheric
warm advection provides a potential focus for an upscale growing and
organizing cluster near a warm front across central/eastern Kansas
into western Missouri overnight. As this occurs, damaging surface
gusts are expected to become the most prominent potential severe
hazard.

...Lower Great Lakes/Allegheny Plateau into Ohio Valley...
Deep-layer shear may be modest, but CAPE on the order of 1000-2000
J/kg ahead of the slowing front may become supportive of storms with
potential to produce severe hail and wind during the day Saturday,
before the onset of more substantive mid-level height rises in the
wake of the mid-level short wave trough.

...Eastern Gulf States...
It is possible that a convectively generated or enhanced
perturbation, digging around the northeastern periphery of
low-amplitude ridging, may contribute to vigorous renewed
thunderstorm development by late Saturday afternoon and evening. In
the presence of a seasonably moist boundary layer with sizable CAPE,
stronger storms may be accompanied by a risk for potentially
damaging wind gusts.

..Kerr.. 05/24/2024

$$
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