SPC AC 131956

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0256 PM CDT Thu Mar 13 2025

   Valid 132000Z - 141200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
   ALABAMA...WESTERN FLORIDA...AND SOUTHERN GEORGIA...

   ...SUMMARY...
   Isolated strong to severe thunderstorms capable of producing hail
   and locally damaging gusts are possible from parts of Alabama, into
   southwest Georgia, and the Florida Panhandle this afternoon and
   early evening.

   ...20z Update...
   Minimal changes were made to the MRGL risk area over parts of the
   Southeast, mainly to trim the western extent. Mid-level subsidence
   behind the weakening vort max over parts of MS/TN will tend to limit
   thunderstorm potential to the west through the remainder of the
   afternoon. To the east, increasing low-level moisture and steep
   lapse rates will support isolated thunderstorms with a risk for hail
   and sporadic damaging gusts.

   Elsewhere, strong mid-level height falls are expected over the
   western US as a powerful upper trough approaches. A few elevated
   thunderstorms are possible within warm air advection over the Upper
   Midwest ahead of shallow returning surface moisture. To the west,
   cool mid-level temperatures overspreading meager low-level moisture
   will also support isolated thunderstorm chances over a broad area
   from the Desert Southwest to the Rockies. Somewhat stronger,
   low-topped convection is possible along the cold front from southern
   AZ into far western NM this evening and tonight. Given the strength
   of the wind fields aloft, a few severe gusts will be possible.
   Though, the very limited buoyancy should limit the severe threat.
   See the previous discussion for more info.

   ..Lyons.. 03/13/2025

   .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 13 2025/

   ...Southeast...
   A mid-level vorticity maximum over the Mid-South late this morning
   will become less well defined as it moves slowly eastward across the
   TN Valley and Southeast through the period. Stronger mid-level flow
   is expected to remain over southern/coastal portions of the
   Southeast today. But, cold mid-level temperatures (around -18 to -21
   C at 500 mb per 12Z regional soundings) in conjunction with filtered
   daytime heating and modest low-level moistening will support weak
   destabilization from parts of AL into southwest GA, and the FL
   Panhandle. Current expectations are for isolated to scattered
   thunderstorms to develop across these areas through the afternoon,
   as modest ascent with the weakening mid-level trough moves through.
   Most guidance suggests that greater convective coverage may occur
   over parts of southeast AL into southwest GA and perhaps the FL
   Panhandle, in closer proximity to greater low-level moisture and the
   mid-level jet. With modest to sufficient deep-layer shear, clusters
   to marginal supercell structures could pose an isolated threat for
   both severe hail and damaging winds this afternoon through early
   evening. See Mesoscale Discussion 167 for additional details on
   convective development and evolution through 20Z.

   ...Southern Arizona...
   A cold front will move eastward across southern AZ today, as an
   upper trough progresses over the Southwest. Showers and
   thunderstorms are expected to spread across this region in tandem
   with the front. Winds aloft will be quite strong, as an 80-100 kt
   mid/upper-level jet max digs southward along/near the international
   border. Some higher momentum flow may mix to the surface, and a gust
   could approach severe limits within low-topped convection. However,
   the weak thermodynamic profile would suggest the severe threat will
   remain low.

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
   CURRENT UTC TIME: 2259Z (10:59PM), RELOAD THIS PAGE TO UPDATE THE TIME