SPC Mar 31, 2025 1930 UTC Day 3 Severe Thunderstorm Outlook

SPC 1930Z Day 3 Outlook

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0230 PM CDT Mon Mar 31 2025

Valid 021200Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE GREAT
LAKES INTO PARTS OF THE MID MS VALLEY AND ARKLATEX...

...SUMMARY...
An outbreak of severe storms is possible Wednesday and Wednesday
night across the Lower Great Lakes, Mid Mississippi Valley, and the
ArkLaTex. Severe wind gusts, very large hail, and significant
tornadoes are expected.

...Synopsis...
No major changes have been made to the outlook, aside from
tightening the gradient in severe probabilities across the southeast
portion of the threat area. An outbreak of severe storms still
appears possible, with a threat of significant tornadoes, widespread
damaging winds, and hail. An upgrade remains very possible in
subsequent outlooks for some portion of the Enhanced Risk area. 

A strong mid/upper-level trough and attendant surface cyclone will
move northeastward across the upper Midwest and Great Lakes regions
on Wednesday, as a powerful jet (80-120 kt at 500 mb) overspreads
parts of Midwest and mid/upper MS Valleys. A cold front attendant to
the cyclone will move eastward, with widespread strong to severe
storms expected along/ahead of the front.  

...Midwest to the Great Lakes and Ohio Valley...
One or more clusters of storms will likely be ongoing Wednesday
morning across parts of IA/MO/IL. An isolated severe threat may
persist through the morning, with some intensification and/or
redevelopment as convection spreads east-northeast in conjunction
with the surface cyclone and cold front. The northward extent of
substantial destabilization remains in question due to the influence
of early convection, but very strong low-level and deep-layer shear
will support a threat of damaging winds and tornadoes if
surface-based storms can be sustained into the Great Lakes region
during the afternoon and evening. 

...Mid Mississippi Valley and vicinity...
Substantial low-level moistening is expected from the ArkLaTex into
the MS/OH Valleys during the day on Wednesday, aided by a
persistently strong (40-60 kt) low-level jet. While the primary
surface cyclone will become increasingly removed from this region
with time, favorable low-level moisture transport and upper-level
difluence will support widespread thunderstorms along/ahead of the
front from IL southwestward into the ArkLaTex region. 

The environment will be quite favorable for tornadic supercells,
with rich low-level moisture, very strong low-level and deep-layer
shear, and at least moderate instability. There will be some
potential for storm interactions and upscale growth given the
likelihood of persistent deep convection within the prefrontal
corridor, but significant tornadoes will be possible if any
supercells can be sustained through the afternoon and evening.
Otherwise, scattered to widespread damaging winds and large to very
large hail will also be possible along/ahead of the front. 

With lingering uncertainty regarding the influence of early-day
storms and potential for long-lived supercells within a corridor of
widespread convection, no upgrade was made with this outlook.
However, it remains very possible that a categorical upgrade will
eventually be needed for some part of the region. 

...Southern Plains into the ArkLaTex overnight...
A broad mid/upper-level trough will remain in place across western
CONUS through the period, and a low-amplitude shortwave may emerge
from this trough late Wednesday night. The cold front will tend to
slow down or stall across the southern Plains into the ArkLaTex,
with renewed low-level jet development forecast into early Thursday
morning. Redevelopment of storms late Wednesday night into Thursday
morning is expected near and north of the front, with moderate to
strong buoyancy and strong deep-layer shear still supportive of
organized convection. A threat for hail and damaging wind gusts will
accompany the overnight storms, and some tornado threat could evolve
with storms in the vicinity of the surface boundary.

..Dean.. 03/31/2025

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