MESOSCALE DISCUSSION 1215
   NWS STORM PREDICTION CENTER NORMAN OK
   0523 PM CDT SAT JUN 27 2015

   AREAS AFFECTED...CAROLINA AND VIRGINIA PIEDMONT INTO COASTAL AREAS

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 272223Z - 280030Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...AT LEAST SCATTERED THUNDERSTORM DEVELOPMENT IS EXPECTED TO
   CONTINUE TO DEVELOP ACROSS MUCH OF THE REGION THROUGH MID TO LATE
   EVENING.  DAMAGING WIND GUSTS APPEAR THE PRIMARY THREAT IN STRONGER
   STORMS.  THE POTENTIAL FOR UPSCALE CONVECTIVE GROWTH INTO AN
   EVOLVING MESOSCALE CONVECTIVE SYSTEM REMAINS UNCLEAR...BUT SEEMS LOW
   AT THIS POINT.  UNLESS THIS OCCURS...THE SEVERE WIND POTENTIAL MAY
   REMAIN SOMEWHAT SPOTTY IN NATURE.

   DISCUSSION...DUE TO GENERALLY WEAK LOWER/MID TROPOSPHERIC LAPSE
   RATES AND LIMITED SURFACE HEATING...MIXED LAYER CAPE ACROSS MUCH OF
   THE REGION IS RATHER MODEST...TO THE SOUTH OF A CONVECTIVELY
   REINFORCED FRONTAL ZONE ACROSS THE EASTERN VIRGINIA PANHANDLE AND
   NORTHERN VIRGINIA INTO THE DELMARVA PENINSULA.  ASIDE FROM A
   CORRIDOR OF STRONGER HEATING TO AROUND 90F ACROSS THE SOUTH CAROLINA
   PIEDMONT...WHERE CAPE MAY BE IN EXCESS OF 2000 J/KG... VALUES APPEAR
   GENERALLY ON THE ORDER OF 1000-1500 J/KG ELSEWHERE.

   IN THE WAKE OF THE CONVECTIVE BAND NOW SPREADING INTO/THROUGH THE
   DELMARVA PENINSULA...SOUTHERLY 850 MB FLOW /AND LOW-LEVEL SHEAR/ IS
   FAIRLY WEAK.  BUT SOUTHWESTERLY MID-LEVEL FLOW IS AT LEAST MODEST IN
   STRENGTH /30-40 KT AROUND 500 MB/....AHEAD OF A SIGNIFICANT SHORT
   WAVE TROUGH GRADUALLY PIVOTING THROUGH THE OHIO VALLEY.  AS THIS
   IMPULSE APPROACHES THE CENTRAL APPALACHIANS LATER THIS
   EVENING...MODELS SUGGEST THAT IT WILL TAKE ON AN INCREASINGLY
   NEUTRAL TO NEGATIVE TILT.  FORCING ASSOCIATED WITH THIS
   FEATURE...COUPLED WITH SEASONABLY STRONG DEEP LAYER SHEAR... WILL
   CONTINUE TO PROVIDE AT LEAST SOME POTENTIAL FOR STRONG/SEVERE STORM
   DEVELOPMENT...INCLUDING ISOLATED SUPERCELLS.  
   GIVEN THE MOIST NATURE OF THE BOUNDARY LAYER...AND PERHAPS SOME
   DRYING IN MID-LEVELS...HEAVY PRECIPITATION LOADING AND EVAPORATIVE
   COOLING NEAR DOWNDRAFTS MAY CONTRIBUTE TO THE RISK FOR STRONG
   SURFACE GUSTS.

   ..KERR/WEISS.. 06/27/2015


   ATTN...WFO...AKQ...MHX...LWX...RAH...ILM...RNK...CHS...CAE...
   GSP...FFC...

   LAT...LON   38787849 38817705 38087627 36687607 35177653 33397950
               32948250 34478275 35928151 38787849