SPC AC 121959

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0159 PM CST Sat Feb 12 2022

   Valid 122000Z - 131200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Isolated thunderstorms may occur across parts of south Florida and
   extreme southern Texas. Severe thunderstorms are not expected.

   ...20Z Update...
   The only change made in this outlook was to trim the General Thunder
   area southward to account for cold frontal passage. A small area of
   extreme southern Texas remains in General Thunder given the presence
   of very modest buoyancy per 19Z mesoanalysis and the latest RAP
   forecast soundings, though this potential should wane by evening. A
   few lightning flashes have recently been noted across south-central
   Texas in association with a band of sleet-producing showers, though
   the expected short duration and low coverage of the flashes
   precludes the introduction of General Thunder. Otherwise, isolated
   thunderstorms still appear possible late tonight into tomorrow
   morning across southern portions of the Florida Peninsula in advance
   of the cold front, where moisture and some buoyancy resides.

   ..Squitieri.. 02/12/2022

   .PREV DISCUSSION... /ISSUED 0958 AM CST Sat Feb 12 2022/

   ...Synopsis...

   A series of midlevel shortwave troughs will migrate across the Gulf
   of Mexico region ahead of the larger-scale mid/upper trough ejecting
   eastward across the southern Plains and Lower MS Valley. At the
   surface, a cold front is oriented just offshore from the
   Middle/Upper TX coast southwestward into far south TX. Most
   thunderstorm activity the remainder of the day will remain over the
   open Gulf waters ahead of the front. However, forecast soundings
   continue to indicate warm advection atop the shallow near-surface
   cool layer, supporting isolated, mostly elevated thunderstorms from
   south TX, northeast along the TX coast into parts of southeast TX
   for a few more hours. 

   Additional thunderstorms are possible this afternoon/evening across
   southeast FL along a modified front/low-level confluence zone.
   Heating along this boundary will result in weak destabilization amid
   moderate effective shear. However, weak 0-3 km flow and poor
   midlevel lapse rates will limit severe potential. As the upper
   trough of the Plains ejects eastward toward the Lower MS Valley
   overnight and the surface cold front pushes east across the Gulf,
   additional thunderstorms are possible late in the period across
   southwest FL and the Keys.

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z