..SEVERE STORM THREAT WITH DAMAGING WINDS AND POSSIBLE ISOLATED TORNADOES OVER NIGHT STAY ALERT!..

 

Mesoscale Discussion 2331
   NWS Storm Prediction Center Norman OK
   0759 PM CST Sat Dec 16 2023

   Areas affected...portions of the southern and central Florida
   Peninsula and Keys

   Concerning...Severe potential...Watch possible 

   Valid 170159Z - 170430Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Strong to potentially severe thunderstorms may move ashore
   from the Gulf of Mexico over the next several hours. Isolated
   tornadoes and damaging gusts are the main threats. The need for a
   Tornado Watch issuance depends on how much instability can precede
   the approaching line of thunderstorms.

   DISCUSSION...A surface low continues to deepen across the eastern
   Gulf of Mexico and approach the FL Peninsula as an upper-level
   trough continues to amplify over the MS Valley. A confluence band
   preceding the aforementioned surface low is comprised of convection
   that has percolated in intensity over the last few hours, and is
   poised to move ashore sometime before Midnight EST. Widespread rain
   and convection have been overspreading the Peninsula for much of the
   day, with 00Z soundings over TBW and MFL depicting low/mid-level
   lapse rates barely exceeding 5 C/km. Despite low 70s F dewpoints,
   buoyancy has been meager so far, though gradual increases in
   instability are possible across southern FL tonight. 

   Shear profiles are impressive ahead of the rapidly deepening surface
   low, with the same aforementioned observed soundings showing very
   large, curved hodographs in the 0-3 km layer. As such, it is not out
   of the question for a few damaging gusts or tornadoes to occur if a
   persistent updraft can develop and ingest any available
   surface-based, unstable parcels. As such, conditions are being
   monitored for the need of a Tornado Watch issuance.

   ..Squitieri/Smith.. 12/17/2023