MESOSCALE DISCUSSION 0487
   NWS STORM PREDICTION CENTER NORMAN OK
   1148 PM CDT TUE APR 28 2015

   AREAS AFFECTED...PARTS OF SRN FL AND THE KEY

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 290448Z - 290615Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...FREQUENT CLOUD TO GROUND LIGHTNING...MARGINALLY SEVERE
   HAIL AND PERHAPS GUSTY WINDS PERHAPS APPROACHING SEVERE LIMITS MAY
   ACCOMPANY AN EVOLVING CLUSTER OF STORMS WHICH COULD REACH NAPLES AND
   ADJACENT FLORIDA GULF COASTAL AREAS BY 07-08Z.  A SEVERE WEATHER
   WATCH PROBABLY IS NOT NEEDED...BUT TRENDS WILL BE MONITORED.

   DISCUSSION...MID/UPPER FORCING DOES NOT APPEAR PARTICULARLY
   STRONG...BUT INFRARED SATELLITE IMAGERY INDICATES THAT CLOUD TOPS
   CONTINUE TO COOL IN ASSOCIATION WITH AN EVOLVING MESOSCALE
   CONVECTIVE SYSTEM NEAR A WEAK FRONTAL WAVE WEST OF THE FLORIDA
   PENINSULA.  FREQUENT CLOUD TO GROUND LIGHTNING IS EVIDENT IN 5
   MINUTE LIGHTNING DATA WITH THE STRONGEST...FORWARD PROPAGATING
   PORTION OF THE CLUSTER WHICH APPEARS LIKELY TO REACH THE NAPLES FL
   AREA TOWARD 07-08Z.  MRMS MESH DATA SUGGEST THAT THIS
   CONVECTION...AND THE STRONGER CORES IN CONVECTION WITHIN THE
   DOWNSTREAM WARM ADVECTION WING...MAY BE PRODUCING AT LEAST
   MARGINALLY SEVERE HAIL...IN THE PRESENCE OF MODEST CAPE AND AND
   MODERATELY STRONG VERTICAL SHEAR BENEATH 35-40 KT 500 MB FLOW.  IT
   DOES NOT APPEAR OUT OF THE QUESTION THAT PEAK GUSTS COULD AT LEAST
   APPROACH SEVERE LIMITS AS THE DEVELOPING COLD POOL ADVANCES INTO
   SOUTHERN FLORIDA GULF COASTAL AREAS.  IT REMAINS A BIT MORE UNCLEAR
   HOW FAR INLAND THIS WILL REMAIN AN APPRECIABLE THREAT.

   ..KERR/THOMPSON.. 04/29/2015


   ATTN...WFO...MFL...KEY...TBW...

   LAT...LON   26808331 26658252 26388191 26158077 26008050 25618048
               25048075 24498177 25258288 25548378 25988433 26378375
               26808331