MESOSCALE DISCUSSION 0986
   NWS STORM PREDICTION CENTER NORMAN OK
   1226 PM CDT FRI JUN 12 2015

   AREAS AFFECTED...PARTS OF WESTERN/CENTRAL NEW YORK STATE

   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

   VALID 121726Z - 121830Z

   PROBABILITY OF WATCH ISSUANCE...80 PERCENT

   SUMMARY...SEVERE STORM POTENTIAL IS EXPECTED TO INCREASE THROUGH THE
   19-21Z TIME FRAME.  THE ISSUANCE OF SEVERE WEATHER WATCH IS
   LIKELY...POSSIBLY A TORNADO WATCH.

   DISCUSSION...AS EVIDENCED BY ONGOING DEEPENING CUMULIFORM CLOUDS TO
   THE WEST OF THE FINGER LAKES REGION...BOUNDARY LAYER DESTABILIZATION
   IS GRADUALLY UNDERWAY TO THE SOUTH OF A DEVELOPING WARM FRONT.  THIS
   SHOULD CONTINUE THROUGH THE AFTERNOON WITH FURTHER SURFACE
   HEATING...WITH MIXED LAYER CAPE INCREASING TO 1000-2000 J/KG ACROSS
   MUCH OF WESTERN INTO CENTRAL NEW YORK STATE TO THE SOUTH OF LAKE
   ONTARIO.  AT THE SAME TIME...FORCING ASSOCIATED WITH AN APPROACHING
   SHORT WAVE IMPULSE...CURRENTLY SUPPORTING AN INCREASE IN CONVECTION
   ACROSS PARTS OF SOUTHWESTERN ONTARIO...APPEARS LIKELY TO BEGIN TO
   SPREAD TO THE EAST/SOUTHEAST OF LAKES ERIE AND ONTARIO AS EARLY AS
   THE 19-21Z TIME FRAME.  AS THIS OCCURS...THE ENVIRONMENT IS EXPECTED
   TO BECOME INCREASINGLY CONDUCIVE TO ORGANIZED CONVECTIVE DEVELOPMENT
   IN THE PRESENCE OF MODERATELY STRONGLY AND SHEARED 40 KT WESTERLY
   DEEP LAYER MEAN FLOW.  30-40 KT WEST SOUTHWESTERLY FLOW AS LOW AS
   850 MB MAY BE A BIT SLOWER TO EDGE EAST OF THE LOWER GREAT
   LAKES...AHEAD OF A WEAK FRONTAL WAVE.  BUT AS IT DOES...ENLARGING
   LOW-LEVEL HODOGRAPHS...PARTICULARLY ALONG THE WARM FRONTAL
   ZONE...MAY BECOME INCREASINGLY FAVORABLE FOR SUPERCELLS WITH A RISK
   FOR TORNADOES.

   ..KERR/CORFIDI.. 06/12/2015


   ATTN...WFO...ALY...BGM...BUF...

   LAT...LON   43697893 43667632 43217474 42127697 42147925 42257962
               42857934 43697893