ACUS01 KWNS 301234
SWODY1
SPC AC 301232

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0732 AM CDT Mon Mar 30 2026

Valid 301300Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MIDDLE AND UPPER MISSISSIPPI VALLEY...

...SUMMARY...
A few severe thunderstorms with large hail, are expected across
parts of the middle and upper Mississippi River Valley tonight
through early Tuesday morning. Isolated strong to marginally severe
storms could occur further east into parts of Lower Michigan early
Tuesday morning as well as over the Texas South Plains this
afternoon and evening.

...Synopsis...
Early-morning satellite imagery shows a relatively zonal pattern in
places across the majority of the CONUS. The only exception is
across the Gulf Coast, which is along the northern periphery of
modest subtropical ridging. Recent surface analysis shows a broad
area of low pressure across the central High Plains/central Plains
with several embedded lows, including one over southwest SD, another
over south-central NE, and another near the OK/KS/CO border
intersection. Modest troughing extends between these features, while
a stationary front extends from the southwest SD low
east-northeastward across southern MN and central WI. At 11Z, mid
50s dewpoints extended from south-central OK into the Mid-South,
with 60s dewpoints farther so from central TX into the Lower MS Valley.

Overall upper pattern is expected to remain predominantly zonal
throughout the period as a low-amplitude shortwave trough moves
along the US/Canada border, accompanied by a strengthening jet
streak. Substantial low-level moisture advection is expected
throughout the day from the southern Plains/Lower MS Valley into the
Mid MS and OH Valleys and Lower MI. By early tomorrow morning, mid
50s dewpoints will likely extend from southern WI across Lower MI
and into the upper OH Valley, demarcating a developing warm front.

Primary area of thunderstorm development anticipated today is in the
vicinity of the developing warm front from the mid/upper MS Valley
across the Lower Great Lakes into the Upper OH Valley and Northeast.
Isolated thunderstorms are also possible with the moist and
confluent environments of the FL Peninsula and the Lower MS Valley
as well as along the dryline in the southern High Plains and
seasonably moist airmass over the Southwest.

....Mid/Upper MS Valley into Lower MI and the Upper OH Valley...

Significant low-level moisture advection is expected throughout the
day into Mid MS Valley, although this advection will be offset
somewhat by strong heating and deep boundary-layer mixing. General
expectation is that upper 50s dewpoints will reach the IA/MO/central
IL vicinity by 00Z, with mid 50s farther north into southern WI and
southern Lower MI. Given negligible large-scale forcing and strong
mixing, capping is expected prevail throughout the day and into the
early evening. However, beginning around 22-00Z, increasing
mid-level moisture coupled with continued low-level moisture
advection and convergence near a weak surface low could result in
convective initiation across central IA. The earliest development
could be surface based with a trend towards more elevated storms
with time and northeastward extent as warm-air advection increase
during the evening. Steep lapse rates and moderate shear support the
potential for supercells with any more sustained updrafts. Large to
isolated very large hail is the primary severe risk. Even with the
elevated storm character, the prevailing warm/dry conditions above
the shallow return moisture could support strong downdrafts with
strong surface gusts.

Farther east, a few instances of small hail are possible from
western PA into western NY with the thunderstorms expected during
the evening and overnight.

...Southern High Plains...

Isolated thunderstorm development is possible along a dryline
forecast to extend from a weak low in western KS southwestward into
the TX Trans Pecos. Buoyancy will be weak and vertical shear modest
so storm structures are not expected to be particularly robust or
long lived. However, high cloud bases and steep low-level lapse
rates could still support a few stronger gusts at the surface.

..Mosier/Marsh.. 03/30/2026

$$
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 * Origin: Capitol City Online (618:250/10)