MESOSCALE DISCUSSION 1840
   NWS STORM PREDICTION CENTER NORMAN OK
   1203 PM CDT WED AUG 03 2011
   
   AREAS AFFECTED...MUCH OF CNTRL/ERN VA...SERN MD
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 031703Z - 031830Z
   
   SCATTERED THUNDERSTORM DEVELOPMENT IS POSSIBLE DURING THE NEXT FEW
   HRS OVER PORTIONS OF CNTRL/ERN VA AND SERN MD. ENVIRONMENT MAY
   SUPPORT A RISK FOR DAMAGING WINDS. CONDITIONS WILL CONTINUE TO BE
   MONITORED FOR POSSIBLE WW.
   
   LATEST VIS SATELLITE IMAGERY INDICATES REMNANT CLOUD COVER
   ASSOCIATED WITH EARLIER MCS OVER THE OH VALLEY IS SPREADING EWD
   ACROSS THE APPALACHIANS. AHEAD OF THIS CLOUDINESS...MOSTLY CLEAR
   SKIES EXIST OVER SRN VA...WITH PARTLY CLOUDY CONDITIONS OVER
   CNTRL/ERN VA AND SERN MD. AREAS OF INSOLATION ARE ALLOWING
   TEMPERATURES TO WARM FROM THE LOW/MID 80S INTO THE LWR 90S AT 16Z.
   THIS HEATING COMBINED WITH SURFACE DEWPOINTS IN THE 70S IS AIDING IN
   THE DEVELOPMENT OF WEAK TO MODERATELY UNSTABLE CONDITIONS /I.E.
   MLCAPE VALUES NEAR 1000 J PER KG/...WITH GREATEST INSTABILITY
   CENTERED OVER S-CNTRL VA WHERE WARMEST SURFACE TEMPERATURES EXIST.
   ATTM...IT IS SOMEWHAT UNCERTAIN HOW THUNDERSTORM INITIATION WILL
   EVOLVE...BUT LATEST HI-RES MODEL GUIDANCE SUGGESTS STORMS WILL FORM
   ALONG LEADING EDGE OF REMNANT MCS CLOUD SHIELD APPROACHING CNTRL VA.
   THIS ACTIVITY IS THEN FORECAST TO SPREAD E-SEWD TOWARD SERN MD/VA BY
   MID TO LATE AFTERNOON. DESPITE CONTINUED BOUNDARY LAYER
   HEATING...WEAK MIDLEVEL LAPSE RATES WILL LIKELY LIMIT MAGNITUDE OF
   INSTABILITY THROUGH THE AFTERNOON. HOWEVER...THE PRESENCE OF 30+ KT
   MIDLEVEL NWLYS COMBINED WITH STEEPENING LOW-LEVEL LAPSE RATES MAY
   FAVOR THE DEVELOPMENT OF MOBILE LINE SEGMENTS OR MULTICELL
   CLUSTERS...POSING MAINLY A THREAT FOR DAMAGING WINDS.
   
   ..GARNER.. 08/03/2011
   
   
   ATTN...WFO...PHI...AKQ...LWX...RNK...
   
   LAT...LON   38027514 36867571 36547659 36548016 37418027 38487853
               38777691 38577587 38027514