MESOSCALE DISCUSSION 0665
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 PM CDT THU APR 28 2011
   
   AREAS AFFECTED...DELMARVA INTO SRN VA
   
   CONCERNING...TORNADO WATCH 251...
   
   VALID 281800Z - 281900Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 251 CONTINUES.
   
   TORNADO WATCH 251 IS SCHEDULED TO EXPIRE AT 19Z BUT LOW LEVEL WINDS
   HAVE YET TO VEER SIGNIFICANTLY.  THIS HAS ALLOWED AN AXIS OF MODEST
   INSTABILITY TO LINGER ACROSS THE TIDEWATER REGION AHEAD OF THE MAIN
   COLD FRONT.  THERE IS SOME CONCERN THAT NEW DEVELOPMENT MAY OCCUR
   ALONG WRN FRINGE OF MOIST/INSTABILITY PLUME WHICH WOULD NECESSITATE
   AN EXTENSION OF THE ONGOING SEVERE THREAT.  A NEW WW MAY BE REQUIRED
   TO ACCOUNT FOR THIS SCENARIO.
   
   ..DARROW.. 04/28/2011
   
   
   ATTN...WFO...PHI...AKQ...LWX...
   
   LAT...LON   36637840 39127711 39527580 38367497 36557593 36637840