SPC Mar 18, 2025 0600 UTC Day 2 Convective Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1255 AM CDT Tue Mar 18 2025

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PART OF
ILLINOIS AND INDIANA...

...SUMMARY...
Scattered severe thunderstorms are possible on Wednesday across
parts of eastern Illinois and western Indiana from mid-afternoon to
early evening. Severe gusts and hail will be the primary threats.

...Upper Midwest/Lower Ohio Valley/Tennessee Valley...
A broad cyclonic flow pattern will be in place over much of the
continental U.S. on Wednesday. At the mid-levels, a trough will move
from the central Plains into the Ozarks, as southwest flow
strengthens over the Ohio and Tennessee Valleys. At the start of the
period, a cluster of thunderstorms associated with an isolated large
hail threat, will be ongoing over parts of Iowa and southern
Wisconsin. At the surface, a low will move eastward into northern
Illinois by afternoon, as low-level moisture increases across the
mid Mississippi Valley. A north-to-south corridor with surface
dewpoints in the 50s F will setup from southeast Missouri into
south-central Illinois. A 50 to 60 knot low-level jet will
consolidate over the extreme western portion of the lower Ohio
Valley.

Thunderstorms appear likely to initiate during the mid afternoon,
along and near the moist axis, and to the west of the low-level jet.
These storms will move eastward into the Ohio and Tennessee Valleys
in the late afternoon and early evening. Although instability will
remain weak along the moist axis, organized cells could develop
across eastern Illinois and western Indiana within an area of strong
large-scale ascent. Forecast soundings in eastern Illinois by late
afternoon have MUCAPE peaking in the 400 to 600 J/kg range, with
very strong deep-layer shear in excess of 80 knots. Cells that can
persist in this environment could produce severe gusts and hail.

...Central Gulf Coast States...
Cyclonically-curved mid-level southwest flow will be in place across
much of the Southeast on Wednesday. The entrance region of a 90 to
100 mid-level jet will overspread the Ark-La-Tex, as a cold front
moves eastward into the central Gulf Coast states. Ahead of the
front, surface dewpoints will be mostly in the upper 50s and lower
60s F. During the late afternoon, isolated thunderstorms are
expected to develop just ahead of the front in an area of focused
low-level convergence from north-central Mississippi into northwest
Alabama. Forecast soundings in north-central Mississippi at
00Z/Thursday have MUCAPE around 500 J/kg, with 0-6 km shear near 70
knot. This could be enough for an isolated severe threat associated
with the stronger multicells, and perhaps a rotating storm.
Marginally severe gusts and hail will be possible.

..Broyles.. 03/18/2025

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