ACUS01 KWNS 011258
SWODY1
SPC AC 011257

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 AM CDT Thu May 01 2025

Valid 011300Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER MS
VALLEY THROUGH THE TN AND OH VALLEYS INTO THE LOWER GREAT
LAKES...AND FROM THE TX/OK PANHANDLES EASTWARD ACROSS OK AND NORTH TX....

...SUMMARY...
Lines and/or clusters of strong to severe thunderstorms are likely
to impact parts of the Ohio Valley into lower Great Lakes, parts of
the lower Mississippi Valley, and the southern Great Plains this
afternoon through tonight.

...Synopsis...
Early morning satellite imagery shows several shortwave troughs
across the CONUS, including one entering the Lower MO Valley/Ozarks
vicinity, another moving into NE, and another off the southern CA
coast. The lead wave is forecast to progress quickly northeastward
through the OH Valley and Great Lakes while losing amplitude under
the increasingly confluent flow aloft. At the same time, another
shortwave trough will drop southeastward through the northern High
Plains into the northern/central Plains, leading to some
amplification of the upper troughing across the north-central CONUS.

Recent surface analysis revealed several lows within a broad area of
low pressure across the central CONUS, one over west-central IL,
another near the SD/ND/MN border intersection, and a third over
north-central OK. A warm front extends eastward from the low over
west-central IL, while modest troughing extends between the Upper
Midwest low and the one over north-central OK.

The west-central IL low is expected to deepen throughout the day as
it moves northeastward ahead of its parent shortwave, with the
attendant warm front advancing northward as well. The northernmost
surface low is expected to progress slowly eastward as well, with
its associated surface troughing also drifting eastward. A more
stationary pattern is anticipated in the vicinity of the OK low
throughout much of the period.

...TN/OH Valleys into the Lower Great Lakes...
Low 60s dewpoints are already in place across the Lower OH and TN
Valley this morning. Continued northward/northeastward advection of
this low-level moisture is anticipated today as the surface low
progresses northeastward. This increased moisture coupled with
modest heating will help support moderate buoyancy across much of
the region by early afternoon. Broad large-scale ascent and surface
troughing are expected over the region amid this destabilization,
which is forecast to result in widespread thunderstorms during the
afternoon and evening. The convective mode will likely be dominated
by linear structures, with one or more convective lines possible.
Primary severe risk will be damaging gusts, supported by moderate
southwesterly flow in the lower troposphere. Some hail is also
possible, particularly during cell mergers. The tornado risk will be
low but non-zero, as veered low-level flow limits the low-level shear.

...Lower MS Valley...
The airmass across the region is expected to quickly destabilize as
low-level moisture advects back into the region in the wake of the
convection currently moving through. Upper 60s dewpoints coupled
with modest heating will result in moderate to strong buoyancy and
no convective inhibition by the early afternoon. Even modest
low-level convergence should be enough to initiate deep convection,
but any remnant outflow could also act as a focus for convective
initiation. Robust updrafts are expected with initial development,
with a quick trend towards outflow-dominant structures. Large hail
and damaging gusts are the primary risks.

...TX/OK Panhandles into much of OK and north TX...
Low-level moisture is expected to advect back northwestward into the
TX Panhandle throughout the day. Cold mid-level temperatures are
already in place (-16 deg C at 500 on the 12Z AMA sounding), so this
added low-level moisture coupled with glancing ascent will likely
result in late evening thunderstorm development. Most of the convection-allowing guidance is suggesting these storms will grow
upscale quickly into an MCS, with some of guidance suggesting it
could be quite and capable of producing significant wind gusts as it
moves eastward across the TX Panhandle and into OK.

Additionally, gradual increase in the low-level moisture beneath
cold mid-level temperatures and associated steep mid-level lapse
rates will result in strong buoyancy across southern OK. Modest
warm-air advection could result in convective initiation across this
region amid an environment that supports very large hail.

Complex interaction is possible between the potential MCS and the
more cellular development ahead of it, but some severe threat
appears possible through early tomorrow morning.

..Mosier/Jewell.. 05/01/2025

$$
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ACUS01 KWNS 031251
SWODY1
SPC AC 031250

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0750 AM CDT Sat May 03 2025

Valid 031300Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CAROLINAS...MID-ATLANTIC STATES...AND NEW ENGLAND...

...SUMMARY...
Strong to severe storms are possible this afternoon into evening
from parts of the Carolinas into the Mid-Atlantic and Northeast. An
isolated severe threat may develop across the Southeast, and also
across parts of the Great Basin.

...Carolinas/Mid-Atlantic States to Southern New England...
Thinking remains that the primary severe risk will focus today
across parts of the Mid-Atlantic into southern New England,
including western/northern Virginia and parts of West
Virginia/Maryland into southern/eastern Pennsylvania to southeast
New York and southern New England. Even with higher-level cloud
cover spreading into the region, ample heating will occur within the
prefrontal warm sector, generally coincident with near 60/lower 60s
F surface dewpoints in the lee of the Appalachians, with upwards of
1000 J/kg MLCAPE possible especially across parts of
Virginia/Delmarva into southeast Pennsylvania and New Jersey. A belt
of moderately strong mid-level southwesterly flow in advance of the
slow-moving mid/upper trough will provide sufficient deep-layer
shear for some storm organization, coincident with the moderately
buoyant warm sector.

Organized cells/clusters should develop during the afternoon from
the Mid-Atlantic into southern New England, as a frontal wave
and modestly enhanced low-level jet move northeastward across the
region. These storms will pose a threat of damaging winds and
isolated hail, and possibly some localized tornado potential.

Farther south, scattered storm development is expected during the
afternoon near/east of the Blue Ridge. Moderate buoyancy/shear and
relatively steep low-level lapse rates will support a threat of
damaging wind and hail with the strongest storms.

...Southeast States/Tennessee Valley...
Several linear bands of storms and possibly multiple weak MCVs are
ongoing this morning across the Florida Panhandle, eastern Alabama,
into western/northern Georgia. An isolated severe risk may exist
early today primarily across the Florida Panhandle with an ongoing
linear cluster of storms. Otherwise, subsequent later-day
destabilization is uncertain in the wake of this convection. Some
increase in deep-layer shear and cooling temperatures aloft will
accompany the approaching mid/upper trough, and adequate heating/destabilization could result in redevelopment of strong to
locally severe storms along the cold front during the afternoon and
evening. This could potentially include parts of Alabama, eastern
Tennessee, northern Georgia and eastern Mississippi.

...Nevada into Oregon/Idaho...
Scattered thunderstorms are expected this afternoon across the
northern Great Basin and vicinity, as favorable large-scale ascent
and steep mid-level lapse rates overspread the region. Buoyancy will
generally remain modest (MLCAPE around 500 J/kg or less), but
moderate deep-layer shear and steep low-level lapse rates could
support a few stronger storms capable of localized severe wind gusts
and small to marginally severe hail.

...Parts of the Texas Big Bend/Trans-Pecos region...
Very isolated storm development is possible during the afternoon and
evening, within a post-frontal regime across parts of west Texas.
Guidance varies somewhat regarding the magnitude of destabilization
across the region, though MLCAPE may remain rather modest (around
500 J/kg). Veering wind profiles will support sufficient deep-layer
shear for storm organization, and if somewhat greater instability
materializes, severe probabilities might need to be introduced for
isolated supercell/related hail potential.

..Guyer/Jewell.. 05/03/2025

$$
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