ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 120845
   SPC AC 120845

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0345 AM CDT Wed Mar 12 2025

   Valid 151200Z - 201200Z

   ...SEVERE WEATHER OUTBREAK POSSIBLE ON D4/SAT...

   ...DISCUSSION...
   ...Day 4/Sat - Central Gulf Coast States to the Ohio Valley...

   A strong large-scale upper trough is forecast to quickly move across
   the Plains to the MS Valley on Saturday. An intense jet streak will
   move across the Deep South into the OH Valley as this occurs. At the
   surface, a low secondary to the 980 mb low over the Upper Midwest is
   forecast to develop during the late morning/early afternoon across
   the mid-South. This will aid in further northward transport of rich
   Gulf moisture into portions of the Lower MS Valley and TN Valleys.
   Atop this moisture-primed boundary layer, cold 500 mb temperatures
   are forecast. This may support fairly steep lapse rates, which would
   foster moderate instability across portions of MS/AL amid supercell
   wind profiles. However, some uncertainty remains tied to the
   evolution of convection in the Day 3/Fri period into the morning
   hours of Saturday. Some forecast guidance suggests a relatively
   pristine warm sector will be maintained, or if only isolated
   convection develops overnight/early Saturday, recovery could occur.
   If this scenario unfolds, a concerning severe weather setup
   supporting all-hazard severe could unfold across portions of
   LA/MS/AL through the day and into evening, and eventually spreading
   east into GA overnight. Trends will be monitored closely over the
   coming days and further adjustments to the 30 percent/Enhanced risk
   area may be needed in future outlooks.

   With northward extent, instability will become more limited.
   Nevertheless, sufficient moisture amid intense deep-layer flow will
   support swaths of strong/damaging winds into the Ohio Valley and
   portions of the central Appalachians Saturday and Saturday night.
   Higher outlook probabilities may be needed in subsequent outlooks if
   confidence increases.

   ...Day 5/Sun - North Florida into the Carolinas and Mid-Atlantic...

   A strong upper trough will shift east across the Midwest and
   Southeast on Sunday. Strong deep-layer southwesterly flow ahead of
   the trough will overspread much of the eastern U.S. atop a moist
   boundary layer. Bands of convection will likely produce swaths of
   strong to severe gusts ahead of an eastward-advancing cold front. 

   ...Days 6-8/Mon-Wed...

   An upper trough will move offshore over the Atlantic on Monday,
   while a broad upper ridge spreads across the Plains in its wake.
   Another large-scale upper trough will move across the western U.S.
   on Tuesday, ejecting across the Plains and into the MS Valley on
   Wednesday. Some severe potential could return to parts of the
   central or south-central states toward the end of the period with
   this system, but current model forecasts suggest moisture return in
   the wake of the Day 4/5 system will remain poor. Trends will be
   monitored over the coming days.

   ..Leitman.. 03/12/2025

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