MESOSCALE DISCUSSION 2056
   NWS STORM PREDICTION CENTER NORMAN OK
   0147 PM CDT THU AUG 25 2011
   
   AREAS AFFECTED...PORTIONS OF SRN...CNTRL...AND NRN VA
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 251847Z - 251945Z
   
   TSTMS FORMING ALONG A PRE-FRONTAL SFC TROUGH WILL POSE A RISK FOR AT
   LEAST ISOLATED DMGG WIND GUSTS. CONVECTIVE TRENDS ARE BEING
   MONITORED FOR A POSSIBLE WW.
   
   LATEST RADAR IMAGERY SHOWS RECENT INTENSIFICATION OF SCT TSTMS NEAR
   THE BLUE RIDGE MTNS OF WRN VA. THESE TSTMS ARE FORMING ALONG A
   PRE-FRONTAL SFC TROUGH /ANALYZED FROM 20 SW SHD TO 10 NW ROA AT
   18Z/...WITH ADDITIONAL FORCED ASCENT PROVIDED BY AN UPPER LEVEL WAVE
   /VISIBLE IN WATER VAPOR IMAGERY/ OVER WV. THE DOWNSTREAM ENVIRONMENT
   HAS BECOME MODERATELY UNSTABLE /MLCAPE VALUES 1000-1500 J/KG/...IN
   PART DUE TO AMPLE SOLAR INSOLATION WITH TEMPERATURES REACHING THE
   LOWER 90S...WHILE PERSISTENT CLOUD COVER ACROSS FAR NRN VA AND
   POINTS NWD HAS LIMITED DESTABILIZATION THUS FAR. STRONGEST MIDLEVEL
   FLOW GENERALLY REMAINS POSITIONED N/E OF THE DISCUSSION AREA /AS
   NOTED IN REGIONAL 18Z SOUNDINGS/...BUT MAGNITUDE OF EFFECTIVE SHEAR
   REMAINS SUFFICIENT TO SUPPORT SOME ORGANIZED TSTMS/CLUSTERS ACROSS
   PORTIONS OF CNTRL/N-CNTRL VA...WITH A PRIMARY THREAT OF DMGG
   WINDS...AS WELL AS HAIL WITH THE STRONGEST CORES. DECREASING
   MIDLEVEL FLOW WITH SWD EXTENT SHOULD LEAD TO A LESS ORGANIZED SVR
   THREAT OVER SRN PORTIONS OF VA...BUT WITH A HOT BOUNDARY LAYER
   SUPPORTING DCAPE VALUES GREATER THAN 1000 J/KG...ISOLATED DMGG
   DOWNBURST WIND REPORTS MAY OCCUR THIS AFTERNOON. TRENDS WILL
   CONTINUE TO BE MONITORED FOR POSSIBLE WW.
   
   ..ROGERS.. 08/25/2011
   
   
   ATTN...WFO...AKQ...LWX...RAH...RNK...
   
   LAT...LON   38277703 37157729 36477823 36467981 36678059 37278048
               38137910 38517831 38757757 38677730 38277703