MESOSCALE DISCUSSION 1730
   NWS STORM PREDICTION CENTER NORMAN OK
   0103 PM CDT FRI AUG 16 2013

   AREAS AFFECTED...PORTIONS OF SRN GA AND NRN FL

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 161803Z - 162030Z

   PROBABILITY OF WATCH ISSUANCE...5 PERCENT

   SUMMARY...AN ISOLATED DAMAGING WIND GUST WILL BE POSSIBLE THIS
   AFTERNOON.

   DISCUSSION...A PLUME OF RICH DEEP MOISTURE WITHIN A WARM CONVEYOR
   BELT E OF A MID-LEVEL TROUGH OVER PARTS OF THE SERN STATES IS
   CHARACTERIZED BY GPS PW VALUES OF 2.0-2.2 INCHES ACROSS THE
   AREA...WITH SFC OBS INDICATING DEWPOINTS IN THE LOWER AND MIDDLE
   70S. THE 12Z RAOBS AT CHS...JAX...AND TLH INDICATE DEEP LAYERS OF
   NEARLY MOIST-NEUTRAL PROFILES IN SECTIONS OF THE LOWER/MIDDLE
   TROPOSPHERE WITH GENERALLY POOR MID-LEVEL LAPSE RATES.
   HOWEVER...LOW-LEVEL LAPSE RATES ARE DIURNALLY STEEPENING IN RESPONSE
   TO MODEST INSOLATION IN AREAS OF AT LEAST PARTIAL SUNSHINE --
   GENERALLY ON THE WARM SIDE OF A WAVY...QUASI-STATIONARY...
   CONVECTIVE-OUTFLOW-AUGMENTED SYNOPTIC BOUNDARY. EARLY THIS
   AFTERNOON...THIS BOUNDARY WAS ANALYZED FROM SSE OF SAVANNAH GA TO
   WEAK LOW PRESSURE NW VIDALIA GA TO ANOTHER WEAK LOW NNE OF MARIANA
   FL THAT EXTENDS FARTHER SW INTO THE NRN GULF OF MEXICO.

   CONVECTION IS FORECAST TO INCREASE IN COVERAGE AND INTENSITY DURING
   THE NEXT FEW HOURS AMIDST A MODERATELY TO STRONGLY UNSTABLE AIR MASS
   AND VERY WEAK INHIBITION PER MODIFIED 12Z RAOBS. FOCI FOR ENHANCED
   THUNDERSTORM COVERAGE INCLUDE THE FOLLOWING:
   /1/ CONVERGENCE ALONG THE SYNOPTIC BOUNDARY...
   /2/ ASCENT ACCOMPANYING DIFFERENTIAL HEATING ZONES OVER THE
   PERIPHERIES OF MULTI-LAYERED CLOUD DECKS SCATTERED ACROSS THE
   AREA...
   /3/ LIFT INVOF REMNANT OUTFLOW BOUNDARIES ACROSS THE REGION...AND 
   /4/ ASCENT INVOF A SFC CONFLUENCE AXIS THAT ENTERS SWRN PARTS OF THE
   MCD AREA FROM THE MIDDLE AND EASTERN GULF.

   UPDRAFT INTENSITY WILL LARGELY BE MITIGATED BY WEAK MID-LEVEL LAPSE
   RATES. HOWEVER...WITH A BAND OF 20-25 KT OF MID-LEVEL FLOW E OF THE
   TROUGH -- STRONGEST NEAR THE AUGMENTED SYNOPTIC BOUNDARY -- A FEW
   MARGINALLY ORGANIZED STORM CLUSTERS MAY OCCUR. AND...WITH THE HIGH
   PW IN PLACE SUPPORTING ABUNDANT WATER LOADING...AN ISOLATED DMGG
   WIND GUST CANNOT BE RULED OUT.

   ..COHEN/KERR.. 08/16/2013


   ATTN...WFO...CHS...MLB...TBW...JAX...FFC...TAE...

   LAT...LON   30348560 31628343 32298231 32348144 31968106 30788146
               29308103 28788165 28848264 29878385 29658527 30348560