SPC May 1, 2025 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0758 PM CDT Wed Apr 30 2025

Valid 010100Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS
PARTS OF SRN AND ERN TX...NRN LA...ERN AR...NWRN MS...WRN TN...SERN
MO...SRN IL AND SRN IN...

...SUMMARY...
The risk for strong to severe thunderstorm development may continue
into late evening across parts of the southeastern Great Plains into
Mid South and lower Ohio Valley, before waning overnight.

...01Z Update...
A notable mid-level short wave trough emerging from the Southwest
has reached the southern Great Plains and is forecast to pivot
northeastward toward the middle Mississippi Valley overnight,
downstream of similar amplitude trough digging across the
Canadian/U.S. border.  The lead perturbation has been preceded by
extensive convection the past day or two across the southern Great
Plains, which has substantially stabilized the boundary layer across
much of north Texas and Oklahoma.  

The leading edge of the convective outflow has remained a focus for
vigorous thunderstorm development.  While this boundary may be
slowing or gradually stalling south of Longview and Temple TX, 3-4+
mb 2-hourly surface pressure rises are now evident in 00Z surface
observations in a corridor across the Shreveport LA, El Dorado and
Little Rock AR vicinities, with more modest falls (1-1.5 mb
2-hourly) at Memphis TN and Walnut Ridge AR.  Based on this, it
appears that the gust front will advance eastward across the
Mississippi River through late evening.  As it does, it may continue
to be accompanied by gusts approaching or briefly exceeding severe
limits, but less unstable updraft inflow probably will gradually
contribute to weakening convective trends.

It does appear that at least a modest surface low is in the process
of forming downstream of the lead short wave trough, across
southwestern Missouri.  As this feature migrates northeastward
tonight, models indicate that a belt of 30-35+ kt southerly flow
around 850 mb, now extending across southeastern Texas through the
Mid South, will shift across the lower Ohio Valley toward the lower
Great Lakes region.  Despite the strengthening wind fields and
shear, ongoing thunderstorm development near a surface warm front,
east-northeast of St Louis toward the Cincinnati area, is not
expected to undergo substantive further intensification, and
probably will begin to wane as the boundary-layer stabilizes with
the loss of heating, and better low-level moisture return becomes
cut off by the progression of the convective outflow to the south.

Across Texas, weakening wind fields/shear and forcing for ascent
probably will lead to weakening convective trends by late evening,
as the boundary-layer stabilizes with the loss of daytime heating.

..Kerr.. 05/01/2025

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