MESOSCALE DISCUSSION 1609
   NWS STORM PREDICTION CENTER NORMAN OK
   0636 PM CDT WED JUL 13 2011
   
   AREAS AFFECTED...SRN VA...MUCH OF NC
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 638...
   
   VALID 132336Z - 140030Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 638
   CONTINUES.
   
   THREAT OF DMGG WIND AND HEAVY RAINFALL CONTINUES FOR WW 638.
   
   TWO SEPARATE CLUSTERS OF STORMS CONTINUE ACROSS THE WW AREA...ONE
   ALONG A SWD SAGGING COLD FRONT ACROSS VA...AND ANOTHER HEAVY
   RAINFALL PRODUCING MCS ALONG THE CAROLINA BORDERS. 
   
   FOR THE NRN CLUSTER IN VA...FRONTAL FORCING WILL CONTINUE TO ALLOW
   STORMS TO DEVELOP IN ADVANCE OF A STRONGER UPPER WAVE...OBSERVED ON
   WV IMAGERY ACROSS SRN PA. 30-40 KTS 0-6 KM EFFECTIVE SHEAR WILL
   SUPPORT ORGANIZED CLUSTERS CAPABLE OF DMGG WINDS ALONG THE WRN MOST
   STORMS...WHILE SHEAR VECTORS ORIENTED PARALLEL TO THE COLD FRONT
   WILL GENERALLY LEAD TO STORM INTERFERENCE AND A HEAVY RAINFALL
   THREAT FOR THE ERN MOST STORMS. STORMS WILL GRADUALLY WEAKEN AS THE
   FRONT SAGS SWD INTO A RAIN COOLED AIR MASS LEFT BY THE SRN MCS.
   
   FOR THE MCS NEAR THE CAROLINA BORDER...STORM INTERFERENCE HAS LED TO
   A HEAVY RAINFALL THREAT...WHILE AN EXTREMELY NARROW CORRIDOR OF
   INSTABILITY REMAINS NEAR THE COAST. HOWEVER...DIURNAL COOLING
   CONTINUES TO STABILIZE THE SURFACE...AND WILL GRADUALLY LEAD TO
   ELEVATED STORMS AND A SUBSEQUENTLY DIMINISHING THREAT OF DMGG WINDS.
   
   ..HURLBUT.. 07/13/2011
   
   
   ATTN...WFO...AKQ...MHX...LWX...RAH...ILM...RNK...CAE...
   
   LAT...LON   36527972 37807862 37737626 36017693 33967850 33977951
               35338016 36527972