MESOSCALE DISCUSSION 0638
   NWS STORM PREDICTION CENTER NORMAN OK
   0550 PM CDT WED APR 27 2011
   
   AREAS AFFECTED...WRN/CNTRL NY...CNTRL/ERN PA
   
   CONCERNING...TORNADO WATCH 236...
   
   VALID 272250Z - 272345Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 236 CONTINUES.
   
   TORNADO/DAMAGING WIND THREAT PERSISTS WITHIN THIN QLCS STRETCHING
   FROM MONROE COUNTY NY TO BLAIR COUNTY PA AS OF 2240Z AND DISCRETE
   CELLS OUT AHEAD OF THIS LINE IN CNTRL PA. DESPITE LINE ORIENTATION
   NEARLY PARALLEL TO THE DEEP-LAYER FLOW...LOW-LEVEL SHEAR REMAINS
   QUITE STRONG WITH 0-1 KM SRH AOA 300 M2/S2 AND IS EXPECTED TO
   STRENGTHEN FURTHER THROUGH THE EVENING. THIS MAY COMPENSATE FOR THE
   LOSS OF DIURNAL HEATING WITH UPPER 50S TO MIDDLE 60S SURFACE DEW
   POINTS PRESENT DOWNSTREAM. IF TSTM ACTIVITY IS ABLE TO BE MAINTAINED
   AS IT APPROACHES THE ERN EXTENT OF THE WW...A NEW WW ISSUANCE MAY
   BECOME NECESSARY IN THE 00-02Z TIME FRAME.
   
   ..GRAMS.. 04/27/2011
   
   
   ATTN...WFO...BTV...ALY...PHI...BGM...BUF...CTP...LWX...
   
   LAT...LON   42007513 40237526 39687567 39447668 39637812 40507852
               42487801 43887754 44537659 44537576 44327521 43567494
               42007513