SPC Mar 28, 2025 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1122 AM CDT Fri Mar 28 2025

Valid 281630Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
COASTAL TEXAS INTO LOUISIANA AND PORTIONS OF NEBRASKA INTO THE UPPER
MIDWEST...

...SUMMARY...
A low probability tornado/wind threat is forecast through this
evening across parts of coastal Texas into Louisiana. Isolated
severe hail and wind is also possible this evening/tonight from
Nebraska into portions of the Upper Midwest.

...Coastal Texas into Louisiana...
Satellite imagery late this morning shows a mid-level trough over
south-central TX into northeastern Mexico, and a vorticity max over
the middle coastal plain of TX.  Largely displaced from incipient
outflow-generated air from a couple of western Gulf thunderstorm
clusters, southeasterly low-level flow is advecting richer moisture
into southeast TX/western LA.  

Cloud breaks will lead to some heating from the middle to upper
coasts of TX into western LA.  Surface dewpoints ranging from the
upper 60s near the coast to the mid 60s as far north as I-20, will
contribute to 250-1000 J/kg MLCAPE per model forecast soundings. 
Sufficiently enlarged low-level hodographs (0-1 km SRH 100-200
m2/s2) and a moist boundary layer and appreciable 0-3km CAPE, will
support a conditional setup for several mini supercells.  The main
threats with this highly dependent mesoscale scenario would be a
risk for a couple of tornadoes and localized damaging gusts. 
Uncertainty is rather high regarding this forecast due to low
confidence in a few warm sector cells developing this afternoon. 
However, if isolated to scattered storms were to develop, the
greatest potential severe threat would occur primarily in the 18-00
UTC period.  This potential activity would likely diminish by early
to mid evening owing to the loss of daytime heating.

...Nebraska into the Upper Midwest...
Upper ridging will be gradually suppressed today as a low-amplitude
shortwave trough moves eastward across the northern/central Plains
and Upper Midwest through the period.  Modest low-level moisture is
forecast to continue streaming northward along/south of a sharpening
warm front across MN/WI, and east of a cold front that will develop
southward across parts of the northern/central Plains by this
evening. Isolated to scattered thunderstorms may develop by mid to
late evening along/near both fronts as low-level warm advection
strengthens, from central NE northeastward into southern MN and
central WI. Steep mid-level lapse rates will aid in the development
of moderate MUCAPE, while deep-layer shear appears marginally
supportive of organized convection. Any sustained thunderstorms
could produce isolated severe hail and damaging winds. This activity
will likely be elevated with eastward extent into the Upper Midwest
through the evening and overnight, with a continued hail threat.

..Smith/Moore.. 03/28/2025

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