MESOSCALE DISCUSSION 2175
   NWS STORM PREDICTION CENTER NORMAN OK
   0600 PM CDT TUE SEP 13 2011
   
   AREAS AFFECTED...NWRN PA...AND WRN-NRN NY
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 132300Z - 140000Z
   
   A FEW STRONG TO SEVERE TSTMS WILL BE POSSIBLE DURING THE EARLY
   EVENING FROM NWRN PA INTO WRN-NRN NY.  GIVEN TIME OF DAY WITH THE
   ONSET OF BOUNDARY LAYER COOLING/STABILIZATION...SPATIOTEMPORAL
   LIMITATIONS PRECLUDE THE NEED FOR A WW. 
   
   EARLY EVENING VISIBLE/REGIONAL RADAR IMAGERY AND LIGHTNING DATA
   INDICATED A COUPLE NE-SW ORIENTED BANDS OF CONVECTION /WITH EMBEDDED
   TSTMS/ IN LEE OF LAKES ONTARIO AND ERIE.  THIS CONVECTION IS LOCATED
   ALONG LAKE BREEZES AND A PRE-FRONTAL WIND SHIFT THAT HAS JUST MOVED
   E AND S OF LAKE ERIE.  THE NEWD EXTENSION OF LATE DAY INSTABILITY
   EXTENDED INTO NERN OH/NWRN PA...WHILE INSTABILITY WAS WEAKER FARTHER
   NNEWD TO IN LEE OF LAKE ONTARIO.  9 KM CAPPI IMAGERY SHOWED THE MORE
   PERSISTENT STORMS LOCATED OVER NWRN PA INTO ADJACENT SWRN NY AND FAR
   NERN OH WHERE THE GREATER INSTABILITY WAS JUXTAPOSED WITH THE SRN
   EXTENT OF STRONG EFFECTIVE BULK SHEAR.  A FEW OF THESE STORMS COULD
   PRODUCE HAIL APPROACHING SEVERE VALUES...GIVEN PROXIMITY TO STEEPER
   MIDLEVEL LAPSE RATES OVER THE OH VALLEY.  DESPITE WEAKER INSTABILITY
   IN LEE OF LAKE ONTARIO...STRONG EFFECTIVE BULK SHEAR MAY CONTINUE TO
   SUPPORT A COUPLE OF STRONGER UPDRAFTS YET THIS EVENING WITH AN
   ISOLATED THREAT FOR STRONGER WIND GUSTS AND/OR SMALL HAIL.
   
   ..PETERS.. 09/13/2011
   
   
   ATTN...WFO...BTV...ALY...BGM...BUF...CTP...PBZ...CLE...
   
   LAT...LON   41367909 41148050 41438125 42038036 42867843 43197706
               43597609 44247532 44277460 43217503 42207701 41667851
               41367909