MESOSCALE DISCUSSION 0676
   NWS STORM PREDICTION CENTER NORMAN OK
   1135 AM CDT SAT APR 23 2005
   
   AREAS AFFECTED...VA...MD...SRN PA
   
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL 
   
   VALID 231635Z - 231830Z
   
   ...SEVERE THUNDERSTORM WATCH MAY BE REQUIRED FOR PORTIONS OF THE
   MIDDLE ATLANTIC...
   
   STRONG HEATING AHEAD OF UPPER TROUGH HAS AIDED DESTABILIZATION EAST
   OF THE APPALACHIANS FROM NRN NC INTO EXTREME SRN PA.  AS A
   RESULT...LOW LEVEL LAPSE RATES ARE NOW RELATIVELY STEEP WITH
   7.5-8C/KM VALUES OBSERVED.  THIS SUPPORTS THE RECENT BOUNDARY LAYER
   CU DEVELOPMENT AS SCATTERED SHOWERS ARE SLOWLY DEEPENING.  WITH TIME
   THUNDERSTORMS WILL EVOLVE...POSSIBLY BECOMING ORGANIZED IN THE FORM
   OF A SQUALL LINE WITH EMBEDDED BOWS ALONG LEADING EDGE OF STRONGEST
   FORCING.  WW WILL BE CONSIDERED FOR THIS AREA BY 17-18Z.
   
   ..DARROW.. 04/23/2005
   
   
   ATTN...WFO...AKQ...CTP...LWX...RNK...
   
   37257908 38937840 40067871 39657685 37207696