MESOSCALE DISCUSSION 1480, AREAS AFFECTED...UPSTATE NY...NRN NEW ENGLAND CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

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MESOSCALE DISCUSSION 1480 NWS STORM PREDICTION CENTER NORMAN OK 1102 AM CDT TUE JUL 17 2012 AREAS AFFECTED...UPSTATE NY...NRN NEW ENGLAND CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 171602Z - 171700Z PROBABILITY OF WATCH ISSUANCE...95 PERCENT SUMMARY...CONVECTIVE INITIATION IS EXPECTED N OF THE INTERNATIONAL BORDER BY 17-18Z. THE W-E ORIENTED LINE OF STORMS WILL THEN PROGRESS SWD INTO UPSTATE NY AND NRN NEW ENGLAND...WITH A PREDOMINANT THREAT OF DMGG WINDS AND PERHAPS A FEW TORNADOES. HAIL WILL BE POSSIBLE WITH ANY INITIALLY DISCRETE STORMS THAT CAN DEVELOP. A WW APPEARS LIKELY BY 17-18Z. DISCUSSION...INITIAL STRATUS FROM EARLIER CONVECTION IS QUICKLY PROGRESSING EWD...WITH CLEARING AND AMPLE SURFACE HEATING CONTRIBUTING TO WELL ABOVE NORMAL TEMPERATURES. LOCATIONS ACROSS CNTRL AND UPSTATE NY THAT HAVE CLEARED HAVE ALREADY ACHIEVED FORECAST HIGHS APPROXIMATELY FOUR HOURS EARLIER THAN MODEL CONSENSUS FORECAST. AS SUCH...MODERATE SURFACE-BASED DESTABILIZATION IS RAPIDLY OCCURRING...PARTICULARLY NEAR THE INTERNATIONAL BORDER WHERE SURFACE DEW POINTS REMAIN IN THE UPPER 60S TO LOWER 70S. UPSTREAM SOUNDINGS ACROSS MI SUGGEST STEEPER MID-LEVEL LAPSE RATES WILL ADVECT EWD ACROSS THE NORTHEAST...WHILE A DEEP LAYER STRENGTHENING OF WINDS OCCURS AROUND THE BASE OF A HUDSON BAY TROUGH. ATTM...IT APPEARS CONVECTIVE INITIATION WILL OCCUR ALONG A COLD FRONT THAT HAS BEEN REINFORCED BY DIFFERENTIAL HEATING RESIDING ACROSS NRN ME...SRN QC AND ON. A LINE OF BOWING SEGMENTS AND POSSIBLE SUPERCELLS SHOULD THEN PROGRESS SWD...FAVORABLY TIMED WITH STEEP LAPSE RATES/INCREASING DEEP LAYER SHEAR. ..HURLBUT/MEAD.. 07/17/2012 ATTN...WFO...GYX...BTV...ALY...BGM...BUF... LAT...LON 44327600 44987497 45037189 45267119 45187053 44677033 44087067 43707163 43547355 43467544 43617618 44107640 44327600