ACUS01 KWNS 211240
SWODY1
SPC AC 211239

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0739 AM CDT Tue Apr 21 2026

Valid 211300Z - 221200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Organized severe thunderstorms are not currently forecast across the
contiguous United States through tonight.

...IL/IN...

Morning water-vapor imagery shows a subtle disturbance over the mid
MO Valley, which is forecast to quickly move southeast into the
southern Great Lakes by early evening. An associated surface trough
is forecast to develop from Lower MI into southern WI and northern
IL by late afternoon. Despite modest moisture (upper 40s to mid 50s
deg F surface dewpoints) returning northward into the Cornbelt, cold
mid-level temperatures (around -16 to -18 deg C at 500 mb) per
forecast soundings and heating will yield weak instability by
mid-late afternoon. Models continue to show isolated to scattered
storms late today into the evening. It remains uncertain whether a
couple of stronger cells will yield a threat of hail beyond a risk
for small hail. This activity will likely diminish by mid-late
evening as it moves southeast into central portions of IL/IN.

...Central CA...

Strong cyclonic flow associated with a mid-level low and associated
trough will move across central CA into the Great Basin during the
period. Cold temperatures aloft north of the midlevel jet will
support weak instability over parts of the central valleys. Given
early precipitation and clouds, as well as marginal low-level shear,
severe storms appear unlikely. However, a few strong storms may
occur late in the afternoon if sufficient heating occurs behind the
early day rain. Small hail appears most probable with the strongest cells.

..Smith/Thompson.. 04/21/2026

$$

--- ScorpioBBS/QWK v0.31a (Linux/x86_64)
* Origin: Project Scorpio TEST (618:250/6)

ACUS01 KWNS 301248
SWODY1
SPC AC 301246

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Thu Apr 30 2026

Valid 301300Z - 011200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
TEXAS AND COASTAL/SOUTHERN LOUISIANA...

...SUMMARY...
Thunderstorms with isolated large hail and gusty winds will be
possible mainly this evening and tonight across parts of southwest/south-central Texas towards the middle Texas Coast, and
this afternoon across coastal/southern Louisiana.

...Texas...

Strong westerly mid-flow will be maintained across the southern
Plains into the Southeast today, as a mid/upper-level low currently
off the coast of Baja California quickly moves eastward through the
period. A surface front is currently stalled across parts of south
TX, and most of the thunderstorms forecast to develop across TX
through tonight are expected to remain elevated. Ascent preceding
the shortwave trough should eventually encourage convection to
develop near the TX Big Bend late this evening, and spread eastward
towards the middle TX Coast through early Friday morning. Sufficient
MUCAPE and strong cloud-layer shear will support an isolated threat
for severe hail with any elevated supercells that can develop.
Strong to locally damaging winds may also occur as supercells
encounter greater instability across south-central to coastal TX
late tonight, even if they remain slightly elevated. Overall
confidence in coverage of severe convection remains too low to
include greater severe hail probabilities and a Slight Risk with
this update.

...Coastal/Southern Louisiana...

A convectively reinforced surface front is draped across
southern/coastal LA this morning, with thunderstorms ongoing to its
north. Greater instability will exist to the south of the front
across coastal LA this afternoon. Thunderstorms that develop/move
across the front later today could pose some risk for locally
damaging winds and marginally severe hail given weak to moderate
instability and strong deep-layer shear.

...Coastal South Carolina...

Thunderstorms capable of producing occasional strong/gusty winds
should move offshore within the next hour or two. The overall severe
wind threat appears too limited to include 5% probabilities.

..Gleason/Jewell.. 04/30/2026

$$

--- Scorpio BBS
* Origin: (618:250/6)