Storm Prediction Center Mesoscale Discussion 939


   Mesoscale Discussion 0939
   NWS Storm Prediction Center Norman OK
   1109 AM CDT Fri May 23 2025

   Areas affected...southern Florida

   Concerning...Severe potential...Watch unlikely 

   Valid 231609Z - 231915Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Strong thunderstorm development, possibly including an
   isolated supercell or two, may initiate during the next 1-2 hours
   along the Atlantic coast sea-breeze, particularly near or
   north-northwest of the Palm Beach vicinity, before gradually
   increasing through late afternoon across the interior southern
   peninsula.

   DISCUSSION...Deepening convective development is evident along the
   Atlantic coast sea-breeze, south of Melbourne into the Palm Beach
   vicinity.  This is where the latest objective analysis indicates
   that mid-level inhibition is weakening in response to insolation, as
   heating of a seasonably moist boundary layer contributes to
   mixed-layer CAPE increasing in excess of 2000 J/kg.

   Stronger low-level confluence/convergence currently appears focused
   near/northwest of the Palm Beach vicinity, where isolated
   intensifying thunderstorm development might be most probable through
   17-18Z.  In the presence of moderate westerly shear, beneath broadly
   cyclonic, 30+ kt westerly mid-level flow and relatively cool
   mid-level temperatures, the evolution of a supercell posing a risk
   for large hail and perhaps a brief tornado appears possible.

   Thereafter, a gradual further increase in scattered thunderstorm
   development appears possible with continued destabilization
   along/ahead of slowly inland advancing Atlantic and Gulf coast
   sea-breezes.  Aided by interactions with outflow and, perhaps,
   gravity waves generated by earlier initiating convection, the
   convective evolution remains unclear, but widely scattered stronger
   cells across the interior southern peninsula may be accompanied by a
   risk for marginally severe hail and locally damaging wind gusts.

   ..Kerr/Guyer.. 05/23/2025

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...MFL...MLB...TBW...

   LAT...LON   27498104 28038058 26948002 25658004 25518074 25698082
               26098146 26618153 27048147 27498104 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN

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