SPC Mar 13, 2025 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0743 AM CDT Thu Mar 13 2025

Valid 131300Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
MISSISSIPPI SOUTHEAST ACROSS ALABAMA AND INTO THE FLORIDA PANHANDLE
AND WESTERN GEORGIA...

...SUMMARY...
A few severe thunderstorms producing hail and locally damaging gusts
are possible from eastern Mississippi into Alabama, western Georgia,
and parts of the Florida Panhandle today.

...Synopsis...
Water-vapor imagery this morning shows a convectively enhanced
mid-level vorticity max near the AR/TN/MS border and located within
a larger mid-level trough centered over the lower MS Valley.  The
mid-level trough will move southeast over the FL Peninsula by mid
evening with the strongest accompanying belt of mid-level flow
shifting into the northern and eastern parts of the Gulf.  Farther
west, a mid-level ridge will move east across the Great Plains into
the MS Valley as an intensifying trough quickly moves east across
southern CA to the southern High Plains during the period.  A cold
front will push east across the lower CO Valley and Sonoran Desert.

...Northwest Mississippi, Central/Southern Alabama, western Georgia
and the western Florida Panhandle...
South-southwesterly low-level flow this morning is acting to advect
modestly more moisture (950-925 mb layer) into the region this
morning (reference 12 UTC Jackson, Birmingham, and Slidell, LA
raobs).  This moisture is beneath the eastern fringe of an elevated
mixed layer that features steep 700-500 mb lapse rates (7.5 to 8.5
deg C/km per raob data).  Ongoing cluster of showers/storms over
northern MS will probably slowly develop southeast through midday. 
Ample heating to the south/southwest of northwest to
southeast-oriented surface trough will contribute to MLCAPE around
500-1000 J/kg.  As the zone of ascent overspreads the destabilizing
airmass across AL into GA/FL, additional storms are forecast this
afternoon.  Isolated to scattered storm coverage is forecast and a
few of the stronger storms will potentially yield an isolated threat
for severe.  This activity will likely weaken by evening owing to
the loss of heating and departing large-scale ascent.

...Southern Arizona...
As a cold front progresses across southern Arizona, shower and
thunderstorm activity is expected to spread across the region. Flow
aloft will be quite strong, as a 100 kt jet max digs southward
across the Mexico border.  It is possible some higher momentum flow
may mix down to the surface at times for a gust to approach severe
limits within convection.  Overall, the weak thermal profile would
suggest the severe threat will remain low.

..Smith/Dean.. 03/13/2025

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