ACUS01 KWNS 291238
SWODY1
SPC AC 291237

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0737 AM CDT Tue Apr 29 2025

Valid 291300Z - 301200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
WEST TX INTO SOUTHWEST OK...AND FROM THE OH VALLEY INTO THE LOWER
GREAT LAKES...

...SUMMARY...
Scattered severe thunderstorms are possible within a broad swath
from the Lower Great Lakes to the southern High Plains, mainly
during this afternoon to evening. Corridors of greater threat are
expected over the Upper Ohio Valley/Lower Great Lakes and in parts
of west Texas into southwest Oklahoma.

...Synopsis...
Recent satellite imagery shows a well-defined shortwave trough
moving through northwest Ontario and the adjacent Upper Midwest, and
a mature cyclone centered over the central UT/AZ border. The
northern shortwave trough is forecast to move eastward across the
Great Lakes and eastern Canada today while also transitioning to a
more negative tilt. The UT/AZ cyclone is expected to progress
southeastward across AZ and into western NM as an embedded shortwave
trough moves through its base across northern Mexico and into the
southern High Plains.

Early morning surface analysis places a low over eastern Lake
Superior, with a cold front extending southwestward from this low
into central OK where another, weaker surface low exists. The front
continues westward from this second low across the TX Panhandle and
through central NM. The northern low is forecast to progress
eastward across eastern Canada, moving just ahead of its parent
shortwave trough, ending the period over the Canadian Maritimes. The
attendant cold front will also push eastward moving through the OH
and TN Valleys, and much of the Northeast. Southern/western portion
of the front will make limited southerly/southeasterly progress,
with its position becoming more regulated by repeated convective
outflow throughout the day.

Numerous thunderstorms, some severe, are anticipated along the
eastward progressing cold front from the OH Valley into the Lower
Great Lakes and Northeast, as well as farther southwest across the
southern Plains near the stalled boundary.

...Ohio Valley into the Lower Great Lakes...
Ongoing cluster across northeast OK will continue through the Ozarks
this morning before reaching the Lower OH Valley this afternoon. It
seems probable that this cluster will reintensify as it interacts
with the destabilizing airmass over the region. Additional
thunderstorm development appears likely along the front north of
this cluster throughout much of the OH Valley into the Lower Great Lakes.

Strong low/midlevel flow will support development of organized storm
clusters, along with some potential for discrete or embedded
supercells. Scattered damaging winds will be possible, with some
potential for swaths of more concentrated wind damage if any
organized linear segments develop. The strongest low-level flow will
be displaced north of the region, but 35-50 kt in the 850-700 mb
layer will support sufficient low-level shear for some supercell
and/or line-embedded tornado threat. Isolated hail could also
accompany any persistent supercell structures.

...West TX into the Ozarks...
Complex convective evolution is underway across OK this morning as a northeastward progressing convective cluster interacts with the
thunderstorms that developed along the front over
northwest/north-central OK. Current trends and recent guidance
suggest that an MCS will evolve and then track northeastward across
the Ozarks. The airmass downstream is expected to remain supportive
of damaging gusts and large hail for at least the next few hours.

Another round of thunderstorms is anticipated this afternoon both
along the outflow-modulated cold front in OK and northwest TX and
along the dryline in West TX as the airmass destabilizes. Strong
buoyancy and shear will support supercells, particularly from west
TX into southwest OK during the late afternoon where low-level
convergence will be strongest. Large to very large hail will be the
primary threat initially, but strong cold pools and close storm
proximity should result in several clusters capable of strong to
significant gusts. A mesoscale corridor of greater tornado potential
may materialize just east of the surface low where stronger
southeasterly low-level flow and higher low-level moisture may
overlap. Current guidance suggests this would be over northwest TX,
but uncertainty exists regarding the outflow/cold front and surface
low positions, precluding the confidence needed to outlook higher
tornado probabilities.

..Mosier/Jewell.. 04/29/2025

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ACUS01 KWNS 021258
SWODY1
SPC AC 021257

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 AM CDT Fri May 02 2025

Valid 021300Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM
CENTRAL/EAST TEXAS TO THE LOWER MISSISSIPPI VALLEY AND TENNESSEE
VALLEY...

...SUMMARY...
Widespread strong thunderstorm development is expected from parts of
central and eastern Texas to the lower Mississippi and Tennessee
Valleys, and into the Cumberland Plateau by evening. This includes
potential for large hail and damaging wind gusts.

...Southern Plains to Lower Mississippi Valley/Tennessee Valley...
A residual MCS, with diminished intensity since early on the
overnight, persists at daybreak along the Red River and
Texas/Oklahoma border region eastward into the Mid-South largely
paralleling I-40, with a probable related MCV across eastern
Oklahoma. A relatively isolated severe potential will initially
exist with these storms this morning. However, an intensification of related/downstream storms is expected by midday, potentially
spanning parts of Arkansas into western/Middle Tennessee, western
Kentucky, and northern Alabama. Additional severe storm development
will be possible this afternoon northeastward into the middle Ohio
Valley and toward the Cumberland Plateau, as increasing
low-level/deep-layer southwesterly winds overlie a moderately
unstable boundary layer. Multiple organizing storm clusters can be
expected regionally this afternoon into evening.

Farther southwest across central/eastern Texas, while considerable
drying and stabilization is still apparent in observational data
after last evening's MCS, the air mass should steadily recover with
moistening and relatively aggressive destabilization into peak
heating. Initial thunderstorm development will be accompanied by the
potential for large hail, with supercells capable of very large hail
possible especially with west-southwestward extent into the Edwards
Plateau and toward the Rio Grande. Damaging wind potential will also
increase as convection organizes and spreads southeastward into this
evening across central/southeast Texas, and possibly Deep South
Texas tonight.

..Guyer/Jewell.. 05/02/2025

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ACUS01 KWNS 180542
SWODY1
SPC AC 180540

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1240 AM CDT Sun May 18 2025

Valid 181200Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF KANSAS AND OKLAHOMA...

...SUMMARY...
Severe thunderstorms capable of all severe hazards are expected
later today across portions of the central and southern Plains. The
potential for a few strong tornadoes exists across parts of Kansas
and Oklahoma.

...Central/Southern Plains...

Strong upper trough is digging southeast across the Great Basin
early this morning. This feature is forecast to advance into the
Four Corners region by 18z as 500mb speed max translates across AZ
into NM. By early evening, strongest mid-level flow is forecast to
extend across northeast NM into western KS. This evolution will
suppress the height field across the central High Plains such that
large-scale forcing will likely influence the dry line as far south
as I-40 near the TX/OK border.

While several 00z models struggle to develop convection along the
dry line, strong boundary-layer heating is expected across the
southern High Plains. Zero-3km lapse rates will approach dry
adiabatic by late afternoon as surface temperatures soar through the
mid 90s across the eastern TX Panhandle into the TX South Plains. As
a result, deep thermals are expected and isolated thunderstorms
should develop as CINH will prove minimal.

Scattered convection is currently noted across northeast OK into
southeast KS/southwest MO. This activity will likely persist into
the early parts of the day1 period. Strongest low-level moisture
surge should be across western OK into extreme southwest KS as LLJ
will focus across this portion of the Plains early in the period.
While early-day convection may generate locally severe hail/wind,
the primary concern for severe will be with late-day convection.
Current thinking is strong heating along the dry line will prove
instrumental in thunderstorm development as convective temperatures
are breached, sometime after 22z. Primary corridor for initiation
should be across southwest KS into northwest OK. This activity will
be strongly sheared and supercells should mature quickly as they
move northeast toward/across the warm front draped downstream across
KS. Very large hail and tornadoes are certainly a concern with
surface-based convection, while hail is the primary concern with
elevated convection north of the warm front.

It's not entirely clear how much convection will develop along the
dry line south of I40, especially across TX. However, minimal
inhibition warrants concern, as any updrafts that evolve within a
strongly sheared and buoyant air mass should produce at least large hail.

Farther north, left-exit region of mid-level jet will encourage a
secondary corridor of strong/severe thunderstorms from northeast CO
into western NE. Surface low is expected to track across eastern CO
into western KS which will maintain a moist/upslope component to
boundary layer across this portion of the High Plains. Strong
low-level warm advection will assist organized convection as it
spreads northeast during the overnight hours.

..Darrow/Halbert.. 05/18/2025

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