MESOSCALE DISCUSSION 0849
   NWS STORM PREDICTION CENTER NORMAN OK
   0255 PM CDT SAT MAY 16 2009
   
   AREAS AFFECTED...PART OF NRN WV/MUCH OF PA/WRN AND CENTRAL NY
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 311...
   
   VALID 161955Z - 162100Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 311
   CONTINUES.
   
   PRIMARY THREAT AREAS WITHIN WW 311 SHOULD REMAIN ACROSS NRN PA INTO
   NY.
   
   OBJECTIVE ANALYSES INDICATE STRONG INSTABILITY ACROSS CENTRAL PA
   /MLCAPE 1000-1500 J/KG/.  ALTHOUGH INSTABILITY TENDS TO DECREASE
   WITH NWD EXTENT INTO NY...EFFECTIVE BULK SHEAR INCREASES INTO THIS
   REGION AND SUPPORTS STORM ORGANIZATION AS A BROKEN LINE OF STORMS
   PROGRESSES ENEWD ACROSS CENTRAL NY AND NORTH CENTRAL PA.  REGIONAL
   RADARS INDICATED A FEW STORMS WITH DEVIANT STORM MOTIONS /E.G. STORM
   IN SCHUYLER COUNTY NY/ HAVING A TENDENCY TO MAINTAIN LOW LEVEL STORM
   ROTATION...GIVEN 0-1 KM SHEAR VALUES OF 20-35 KT ACROSS WW 311
   SUPPORTING AN ISOLATED TORNADO THREAT.  HAIL AND STRONG WIND GUSTS
   WILL ALSO REMAIN A THREAT WITH STRONGER/SUSTAINED STORMS.
   
   A MORE STABLE BOUNDARY LAYER LOCATED ACROSS NERN/ERN NY...
   DOWNSTREAM OF WW 311...SHOULD CONTINUE TO INHIBIT STORMS FROM
   MAINTAINING A SEVERE WEATHER THREAT INTO THESE AREAS OF NY AND
   PRECLUDE THE NEED FOR A NEW WW.  MEANWHILE...FARTHER SW INTO SWRN
   PA...WEAKER INSTABILITY IS TENDING TO LIMIT STRONGER STORM
   DEVELOPMENT THUS FAR THIS AFTERNOON.
   
   ..PETERS.. 05/16/2009
   
   
   ATTN...WFO...ALY...PHI...BGM...BUF...CTP...LWX...PBZ...
   
   LAT...LON   43777453 41997499 39797606 39697812 39618046 40997984
               42127901 42487866 42977765 43417678 43647629 43777453