MESOSCALE DISCUSSION 0899
   NWS STORM PREDICTION CENTER NORMAN OK
   0340 PM CDT MON MAY 23 2011
   
   AREAS AFFECTED...CNTRL/ERN PA/MD...NRN VA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 338...
   
   VALID 232040Z - 232215Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 338
   CONTINUES.
   
   WW 338 IS SCHEDULED TO EXPIRE AT 22Z. GIVEN THE LIKELIHOOD OF AN
   ISOLATED SEVERE THREAT PERSISTING BEYOND THIS TIME FRAME...A
   REPLACEMENT WW WILL BE COORDINATED BETWEEN 21-22Z ALONG AND E OF
   ONGOING BROKEN LINE OF TSTMS FROM CNTRL PA INTO NRN VA.
   
   AS OF 2030Z...A BROKEN LINE OF TSTMS WAS LOCATED ALONG A CONFLUENCE
   AXIS FROM CLINTON COUNTY PA TO MADISON COUNTY VA. DESPITE SOME
   RECENT WEAKENING NOTED IN RADAR REFLECTIVITY ON THE SRN EXTENT OF
   TSTM CELLS IN NRN VA...ENVIRONMENT ALONG AND EAST OF THE CONFLUENCE
   AXIS REMAINS WEAKLY UNSTABLE ACROSS PA TO MODERATELY UNSTABLE SWD
   INTO NRN VA. EFFECTIVE SHEAR AROUND 40 KT WILL SUPPORT ORGANIZED
   UPDRAFTS PRIMARILY PRODUCING DAMAGING WINDS AND SEVERE HAIL.
   
   ..GRAMS.. 05/23/2011
   
   
   ATTN...WFO...PHI...BGM...CTP...LWX...
   
   LAT...LON   41127764 41787735 42117708 42127616 41977563 41037538
               39777558 39117596 38537644 38347784 38467830 38597827
               41127764