MESOSCALE DISCUSSION 0561
   NWS STORM PREDICTION CENTER NORMAN OK
   1224 PM CDT SAT APR 25 2009
   
   AREAS AFFECTED...NWRN PA...WRN NY
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 251724Z - 251830Z
   
   ISOLD THUNDERSTORMS CAPABLE OF MARGINALLY SVR DMGG WINDS WILL LIKELY
   DEVELOP BY MID AFTERNOON OVER THE TWIN TIERS. EWD MOVING CELLS AND
   SHORT LINE/BOWING SEGMENTS WILL BE FAVORED.
   
   RECENT SATELLITE IMAGERY REFLECTS A CU FIELD BEGINNING TO DEVELOP
   NEAR LAKE ERIE. GENERAL STABLE APPEARANCE OF THE CLOUD FIELD
   SUGGESTS WEAK CINH REMAINS...WHICH WILL LIKELY BE OVERCOME AS
   TEMPERATURES CONTINUE TO WARM TO WELL ABOVE NORMAL VALUES. GOES PWAT
   TRENDS/12Z SOUNDING DATA SHOW HIGHER PWAT/MOISTURE IS BEING ADVECTED
   INTO THE REGION...WHICH COMBINED WITH STEEP LAPSE RATES/MARGINAL
   INSTABILITY WILL SUPPORT THUNDERSTORM DEVELOPMENT BY MID
   AFTERNOON...DESPITE SOMEWHAT UNFAVORABLE DEW POINTS.
   HOWEVER...STEEPENING LOW LEVEL LAPSE RATES...RELATIVE DRY LOW
   LEVELS...AND 30-40 KTS LOW LEVEL FLOW WILL SUPPORT MARGINALLY SVR
   WIND GUSTS IN COMBINATION WITH EVAPORATIONAL COOLING IN DOWNDRAFTS
   BENEATH ANY STORMS THAT ARE ABLE TO FORM. UNIDIRECTIONAL WIND FIELDS
   SUGGEST PREDOMINANTLY CELLULAR AND/OR BRIEF/SHORT LINE SEGMENTS WILL
   BE FAVORED. A WW IS NOT ANTICIPATED DUE TO MARGINAL/ISOLD
   NATURE...BUT AREA WILL CONTINUE TO BE MONITORED.
   
   ..HURLBUT.. 04/25/2009
   
   
   ATTN...WFO...BGM...BUF...CTP...CLE...
   
   LAT...LON   42327646 41937719 41627824 41677949 41957985 42277966
               42677908 42947835 43117705 42797636 42327646