ACUS01 KWNS 021957
SWODY1
SPC AC 021956

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0256 PM CDT Thu Apr 02 2026

Valid 022000Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN...

...SUMMARY...
Severe thunderstorms capable of producing a few tornadoes remain
probable across parts of eastern Iowa, northern Illinois, and
southern Wisconsin this afternoon and evening. Additionally,
damaging thunderstorm winds will be possible from eastern Iowa
northeast into Michigan.

...20z Update IA, IL, MO and southern WI...

Rapid air mass modification is underway to the south of a warm front
lifting northward across the western Great Lakes and upper Midwest.
Clearing beneath the advancing mid-level dry slot may allow
temperatures to warm into the low 70s, with surface dewpoints near
60 F. This will support weak buoyancy amid very strong shear
profiles (0-1 km SRH >300 m2/s2) from observed VADs and regional RAOBs.

Scattered thunderstorms and supercells ongoing over northern MO and
southern IA should mature and present a severe hazard over much of
the ENH area as they spread northeastward through this evening. A
few tornadoes (some strong and fast moving), hail and damaging gusts
are expected. Additional storms may develop within the warm conveyor
belt farther east across IL this afternoon/evening. Upscale growth
into one or more clusters with damaging gusts and a couple tornadoes
is the primary concern.

The main change with the 20z update was to trim thunderstorm and
severe probabilities to the west of the advancing cold front. See
the prior discussion for more information.

..Lyons.. 04/02/2026

.PREV DISCUSSION... /ISSUED 1113 AM CDT Thu Apr 02 2026/

...IA/IL/MO/WI...

Morning water vapor imagery shows a strong shortwave trough over
northeast KS, with an associated mid-level jet and dry-slot rotating
around the base of the trough into western MO. A deep surface low
currently south of OMA will track northeastward across IA this
afternoon, with a tight gradient of low-level moisture and
instability along the track of the low. Very strong low-level shear
and sufficient CAPE in the warm sector will pose a risk of
fast-moving supercells capable of damaging winds, tornadoes
(possibly strong), and hail. The area of greatest concern is over
eastern IA into northern IL and far southern WI. Perhaps the
biggest forecast uncertainty is the widespread cloud cover and
limited diurnal destabilization, but the approaching dry slot may
compensate by mid-afternoon and allow a period of afternoon heating.

The coverage of storms with southward extent is uncertain across
eastern MO and central/southern IL. Recent CAM solutions continue
to show only widely scattered discrete development across this
corridor. However, given the forecast of strong low-level shear and
favorable synoptic forcing, those storms that do form would pose a
risk of damaging winds and a few tornadoes.

...Eastern IL/IN/Lower MI...

Strong southerly low-level winds will maintain 60s dewpoints across
eastern IL/western IN, and result in the warm front lifting
northward into southern Lower MI by this evening. This will provide
a favorable environment for a few severe storms capable of damaging
winds and perhaps a few tornadoes.

$$


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ACUS01 KWNS 292002
SWODY1
SPC AC 292000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Wed Apr 29 2026

Valid 292000Z - 301200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE EDWARDS PLATEAU INTO SOUTH-CENTRAL TEXAS...

...SUMMARY...
Severe thunderstorms are forecast from parts of Texas to the Gulf
Coast states today. Scattered large to very large hail and damaging
winds are the primary risks, with giant hail possible in parts of
south-central Texas.

...20Z Update...
The primary change with this update was the addition of an Enhanced
Risk for portions of the Edwards Plateau into south-central TX --
driven by a CIG2 (intensity level 2/2) hail area. The latest visible
satellite imagery indicates an agitated boundary-layer cumulus field
evolving east of Fort Stockton in Crockett County, where attempts at
isolated convective initiation are underway. Current thinking is
that continued diurnal heating of a moist air mass (lower 70s
dewpoints) and upslope flow enhancements will result in isolated to
widely scattered thunderstorms this afternoon into the evening.
Current thinking is that storms will track/develop southeastward
into a corridor of strong to extreme buoyancy -- driven by steep
midlevel lapse rates (around 8.5 C/km per 12Z DRT sounding) atop the destabilizing PBL. This, combined with a long/straight hodograph
(60-70 kt of effective shear) and modest forcing for ascent will
favor intense discrete/splitting supercells. Given the modest
forcing for ascent, it is unclear how many storms will form in this
corridor, though any sustained supercells will pose a risk of very
large to giant hail (3-4+ inches in diameter).

..Weinman.. 04/29/2026

.PREV DISCUSSION... /ISSUED 1049 AM CDT Wed Apr 29 2026/

...Texas into the Lower Mississippi Valley/Southeast...

Satellite imagery late this morning indicates high momentum
quasi-zonal flow from TX eastward across the central Gulf Coast. An
upstream perturbation over Chihuahua is forecast to move quickly
east today reaching central TX late this afternoon. Isolated to
scattered thunderstorms are forecast to increase in
coverage/intensity mainly along/near a surface front draped from
west-central TX to southern AR. A moisture-rich airmass featuring
lower 70s deg F surface dewpoints south of the front, coupled with a
plume of 8 deg C/km 700-500 mb lapse rates and some diurnal heating,
will contribute to 2000-4000 J/kg of MLCAPE decreasing with east extent.

A few initial thunderstorms clusters north of the surface front over
TX are expected to gradually intensify through early afternoon. The
moderate to very unstable airmass will combine with elongated/nearly
straight hodographs to support supercell development with the
stronger updrafts and an associated risk for large to very large
hail (1 to 3 inches in diameter). Have extended the 15-percent hail
and CIG1 hail delineation farther east into northeast TX and western
LA. For short-term forecast details, please refer to MCD #615.
Eventually upscale growth into one or more clusters is expected to
evolve across LA into the central Gulf Coast states later this
afternoon. Damaging gusts and an isolated risk for large hail will
be the primary hazards with the stronger storms.

Farther west, isolated to widely scattered intense storm development
is forecast across the Edwards Plateau this afternoon. This
activity may eventually focus closer to the Rio Grande later this
evening with a large to very large hail threat persisting well after dark.

...Upper OH Valley into the Mid-Atlantic/North Carolina...

Within large-scale upper troughing over the Great Lakes/Midwest, an
embedded mid-level shortwave trough will move northeastward across
the Mid-Atlantic this afternoon/evening in tandem with an
eastward-moving surface cold front. Only modest boundary layer
moisture is present across the region, with surface dewpoints
generally in the 50s. Forecast soundings over western PA show some
low-level hodograph curvature within a moist environment. Main
uncertainty across the upper OH Valley is the magnitude of
destabilization in this area given ongoing scattered showers and
widespread cloud cover. Nonetheless, a couple of stronger storms
could yield an isolated risk for wind damage and perhaps a brief
tornado later this afternoon, especially near/southeast of a weak
surface low. Farther south, isolated wind/hail will be possible
with the stronger thunderstorms through the late afternoon/early evening.

$$


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