MESOSCALE DISCUSSION 0998
   NWS STORM PREDICTION CENTER NORMAN OK
   0501 AM CDT TUE JUN 09 2009
   
   AREAS AFFECTED...ERN PA/SERN NY SWD TO MD/NRN VA
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 091001Z - 091100Z
   
   ISOLATED STRONG WIND GUSTS AND GENERALLY SMALL HAIL...SOME
   APPROACHING SEVERE VALUES...ARE POSSIBLE WITH THE LINE OF TSTMS
   MOVING EWD THROUGH ERN PA...AND ALSO ATTENDANT TO RECENT TSTM
   DEVELOPMENT OVER NERN VA TO ADJACENT MD /VICINITY OF D.C./.
   
   OBJECTIVE ANALYSES INDICATED A MOIST/MODERATELY UNSTABLE AIRMASS
   EXTENDING NWD IN LEE OF THE APPALACHIANS FROM VA/MD TO ERN PA/NJ. 
   INCREASE IN TSTM INTENSITY /DURING THE LAST 1-2 HOURS/ PER REGIONAL
   RADAR DATA APPEARS TO BE ASSOCIATED WITH LEADING EDGE OF FORCING FOR
   ASCENT /ATTENDANT TO SRN EXTENT OF ONTARIO SHORTWAVE TROUGH/
   SPREADING EWD AND ENCOUNTERING THE MORE MOIST/UNSTABLE AIR MASS. 
   DESPITE THE INCREASE IN STORM INTENSITY...MODEST MID LEVEL LAPSE
   RATES /AROUND 6.5 C/KM/ AND EFFECTIVE BULK SHEAR /25-30 KT/ SUGGEST
   STORMS SHOULD BE MULTICELLULAR AND TEND TO HAVE DIFFICULTY
   MAINTAINING MORE PERSISTENT UPDRAFTS...AND AN OVERALL ATTENDANT
   SEVERE THREAT.  ALTHOUGH SHEAR VALUES ARE GREATER WITH NWD EXTENT
   INTO NY...WEAKER INSTABILITY SHOULD LIMIT STRONGER STORM DEVELOPMENT
   INTO SERN NY.  THESE TSTMS ARE EXPECTED TO MOVE EWD AND OFF THE NJ
   COAST BY MID-LATE MORNING...WHILE FURTHER S THE VA TSTMS MOVE INTO
   THE DELMARVA REGION.
   
   ..PETERS.. 06/09/2009
   
   
   ATTN...WFO...OKX...ALY...PHI...BGM...AKQ...CTP...LWX...
   
   LAT...LON   38437797 39527718 40437626 41317539 41907457 41987406
               41327359 40637374 40117420 39457453 38567514 38047534
               37797622 38437797