MESOSCALE DISCUSSION 0657
   NWS STORM PREDICTION CENTER NORMAN OK
   0521 AM CDT THU APR 28 2011
   
   AREAS AFFECTED...NWRN NC...SWRN THROUGH NRN VA AND NRN MD
   
   CONCERNING...TORNADO WATCH 247...
   
   VALID 281021Z - 281145Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 247 CONTINUES.
   
   SEVERE THREAT CONTINUES ACROSS REMAINING PARTS OF WW 247...THOUGH
   OVERALL THREAT HAS AT LEAST TEMPORARILY DECREASED.
   
   SCATTERED PRE-FRONTAL CONVECTION PERSISTS MAINLY ACROSS NRN VA INTO
   MD. OVERALL TREND HAS BEEN FOR STORMS TO DECREASE IN COVERAGE ACROSS
   CNTRL VA. MODEL SOUNDINGS INDICATE A MODEST WARM LAYER FROM 850-600
   MB...AND ZONE OF DEEPER FORCING FOR ASCENT HAS BEEN SHIFTING NWD
   INTO THE NERN STATES IN ASSOCIATION WITH SHORTWAVE TROUGH EJECTING
   INTO THE GREAT LAKES. OTHER STORMS ARE DEVELOPING ACROSS SWRN VA
   INTO WRN NC ALONG DEEPER BAROCLINIC ZONE ACCOMPANYING THE COLD
   FRONT. SOME OF THIS ACTIVITY COULD POSE A SEVERE THREAT AS IT
   DEVELOPS NEWD WHERE INSTABILITY REMAINS MARGINAL...BUT VERTICAL
   SHEAR AND HODOGRAPHS ARE SUPPORTIVE OF SUPERCELLS AND LEWP
   STRUCTURES.
   
   ..DIAL.. 04/28/2011
   
   
   ATTN...WFO...PHI...AKQ...LWX...RAH...RNK...
   
   LAT...LON   36088062 36228128 38077890 39317785 39647717 39467649
               38187629 38077731 36717822 36088062