SPC Mar 28, 2025 1930 UTC Day 3 Severe Thunderstorm Outlook

SPC 1930Z Day 3 Outlook

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0231 PM CDT Fri Mar 28 2025

Valid 301200Z - 311200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR MUCH OF THE
OHIO VALLEY INTO THE MID-SOUTH...

...SUMMARY...
A widespread/substantial severe-weather episode is forecast across
an area centered on the Ohio/Mid and Lower Mississippi/Lower
Missouri/Tennessee River Valleys.  Very large hail, damaging winds,
and strong tornadoes are expected.

...Synopsis...
A somewhat broad upper-level trough with nebulous structure will
move from the Plains into the Upper Midwest on Sunday. An embedded
shortwave trough will amplify within the broader trough. A surface
low will move from Iowa into the Great Lakes region. A cold front
will move southeastward into areas east of the Mississippi while
dryline will be present in East Texas.

...Upper Midwest/Ohio Valley...
Models indicate some potential for early morning thunderstorm
activity. This activity will likely be tied to the surface
low/low-level warm advection. Some severe risk may accompany these
storms. The question then becomes how this activity will impact
destabilization across parts of Illinois into Indiana/western Ohio.
Wind fields will still support supercells capable of all hazards,
but the overall magnitude of these threats will depend on the degree
of surface heating that occurs.

Much of the Ohio Valley vicinity itself appears that it will not be
impacted directly by early morning convection. This will be a zone
where a favorable overlap of surface heating and stronger low-level
wind fields will exist. Though the cold front will be the initiating
boundary, effective shear vectors are expected to be orthogonal to
it. This should increase the potential for discrete storms and
strong tornadoes in addition to large hail and severe gusts.

...Mid-South...
Ahead of the southeastward moving cold front, dewpoints are expected
to rise to the mid to potentially the upper 60s (the NAM being
typically more aggressive in this regard). Given the presence of an
elevated mixed layer, this region is expected to have little to no
thunderstorms expected during the morning/early afternoon. Surface
heating and increasing mid-level ascent should eventually erode the
cap and allow storms to develop by mid/late afternoon. There is some
indication that a pre-frontal trough/confluence zone may set up.
Should this occur, the potential for discrete storms would increase
along with the potential for a more concerning tornado risk.
Low-level wind fields will likely be somewhat weaker in these areas
given the southward displacement from the surface low. However,
forecast soundings suggest low-level hodograph curvature will be
more than sufficient, particularly beyond early evening. Even
without pre-frontal discrete development, the greater surface
heating expected in this region should allow for widespread severe
storms along the cold front with a threat for large hail, widespread
damaging winds, and QLCS tornadoes.

...East Texas/Sabine Valley...
A dryline feature will serve as the focus for convection. Storms in
this area would more than likely be discrete. Steep mid-level lapse
rates and sufficient effective shear should promote supercells
capable of large/very-large hail as well as severe gusts and
tornadoes. Later in the period, the cold front will surge south and
lead to upscale growth of what activity is ongoing at that time.

..Wendt.. 03/28/2025

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