MESOSCALE DISCUSSION 2043
   NWS STORM PREDICTION CENTER NORMAN OK
   1245 PM CDT MON SEP 28 2009
   
   AREAS AFFECTED...PORTIONS OF UPSTATE NY
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 748...
   
   VALID 281745Z - 281915Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 748
   CONTINUES.
   
   THE THREAT FOR DAMAGING WINDS CONTINUES ACROSS WW AREA. 
   EXTRAPOLATION OF CURRENT STORM MOTIONS SUGGESTS THAT THIS THREAT
   WILL REACH ERN EDGE OF WW PRIOR TO 20Z.  AN ADDITIONAL WW MAY BE
   REQUIRED.
   
   AS OF 1730Z...REGIONAL RADAR IMAGERY INDICATED A STRONGLY
   FORCED...BROKEN BAND OF TSTMS FROM APPROXIMATELY 60 W OF ART TO THE
   LAKE ONTARIO SHORE OF N-CNTRL WAYNE COUNTY...THEN SWD THROUGH
   PORTIONS OF LIVINGSTON...ONTARIO INTO ALLEGANY AND STEUBEN COUNTIES.
   STORM MOTION WAS GENERALLY 250/40-50 KT.  SYNTHESIS OF SATELLITE AND
   SURFACE OBSERVATIONAL DATA INDICATE THAT A 30-40 MN WIDE ZONE OF
   CLEARING IS PRESENT AHEAD OF ONGOING STORMS.  HERE...TEMPERATURES
   HAVE WARMED INTO THE LOWER/MID 60S.  WHEN COUPLED WITH DEWPOINTS IN
   THE LOW/MID 50S AND STRONG DYNAMIC COOLING ALOFT...ENVIRONMENT HAS
   BECOME AT LEAST WEAKLY UNSTABLE WITH MLCAPE OF A FEW HUNDRED J/KG.
   
   CURRENT BUF VWP SHOWS RELATIVELY STRONG WLY FLOW IN THE LOW-LEVELS
   WITH AROUND 50 KT OBSERVED AT 1 KM AGL.  THESE WINDS IN CONCERT WITH
   STEEPENING LOW-LEVEL LAPSE RATES FROM THE W WILL SERVE TO ENHANCE
   DOWNDRAFT POTENTIAL ALONG PRIMARY CONVECTIVE LINE...AS WELL AS ANY
   CONVECTIVE ELEMENTS MOVING OFF THE WARMER WATERS OF LAKE ERIE.
   
   ..MEAD.. 09/28/2009
   
   
   ATTN...WFO...BTV...ALY...BGM...BUF...
   
   LAT...LON   43117888 43477871 43537777 43487685 43837638 44097599
               44247573 44297543 43997507 43427503 43067512 42757582
               42487699 42567803 42687861 43117888