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Mesoscale Discussion 663
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   MESOSCALE DISCUSSION 0663
   NWS STORM PREDICTION CENTER NORMAN OK
   0120 PM CDT SAT MAY 21 2016

   AREAS AFFECTED...NERN GA...NWRN SC...CNTRL/WRN NC...EXTREME SWRN VA

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 211820Z - 212045Z

   PROBABILITY OF WATCH ISSUANCE...5 PERCENT

   SUMMARY...A SLOW INCREASE IN COVERAGE AND INTENSITY OF THUNDERSTORMS
   IS EXPECTED THIS AFTERNOON...WITH A PRIMARY THREAT OF LOCALLY
   DAMAGING WIND.

   DISCUSSION...AT 1815 UTC...A CLUSTER OF THUNDERSTORMS IS ONGOING SE
   OF ATL...WITH ADDITIONAL CONVECTION BEGINNING TO DEVELOP ACROSS THE
   HIGHER TERRAIN OF WRN NC. COVERAGE IS EXPECTED TO CONTINUE
   INCREASING INTO MID-AFTERNOON...AS LARGE-SCALE ASCENT INCREASES
   AHEAD OF A STRONG UPPER TROUGH OVER THE OHIO VALLEY.

   WHILE LAPSE RATES ARE RELATIVELY POOR...DIURNAL HEATING AND LOW/MID
   60S DEWPOINTS ARE RESULTING IN SBCAPE OF 1000-1500 J/KG PER RECENT
   MESOANALYSIS. MODERATE WLY FLOW ALOFT IS SUPPORTING EFFECTIVE SHEAR
   OF 30-40 KTS...WHICH WILL BE SUFFICIENT FOR A FEW ORGANIZED
   STRUCTURES AS THUNDERSTORMS MATURE. WHILE WEAK LOW-LEVEL FLOW WILL
   TEMPER THE SEVERE WIND RISK...ISOLATED DAMAGING WIND GUSTS WILL BE
   POSSIBLE THIS AFTERNOON...PARTICULARLY WITH ANY SMALL BOWING
   SEGMENTS THAT MAY RESULT FROM STORM INTERACTIONS. SMALL HAIL WILL
   ALSO BE POSSIBLE...BUT THE SEVERE HAIL RISK IS EXPECTED TO REMAIN
   LOW DUE TO WEAK LAPSE RATES AND LACK OF STRONGER INSTABILITY. GIVEN
   THE MARGINAL NATURE OF THE THREAT...WW ISSUANCE IS NOT ANTICIPATED.

   ..DEAN/HART.. 05/21/2016


   ATTN...WFO...RAH...ILM...RNK...CAE...GSP...FFC...

   LAT...LON   32918496 34658354 35898173 36578067 36667974 36357930
               35667934 34727994 34178053 33548155 33018300 32528472
               32918496 

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Page last modified: May 21, 2016
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