MD CONCERNING...SEVERE THUNDERSTORM WATCH 489 FOR UPSTATE NY AND NRN NEW ENGLAND

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MESOSCALE DISCUSSION 1484 NWS STORM PREDICTION CENTER NORMAN OK 0232 PM CDT TUE JUL 17 2012 AREAS AFFECTED...UPSTATE NY AND NRN NEW ENGLAND CONCERNING...SEVERE THUNDERSTORM WATCH 489... VALID 171932Z - 172030Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 489 CONTINUES. SUMMARY...A THREAT OF DMGG WINDS...HAIL...AND AN ISOLATED TORNADO PERSISTS ACROSS THE WW AREA. STORMS ARE JUST BEGINNING TO CROSS SWD ACROSS THE INTERNATIONAL BORDER...AND WILL CONTINUE TO PROGRESS THROUGH THE WW AREA THIS AFTERNOON AND EVENING. DISCUSSION...THUNDERSTORMS NEAR THE INTERNATIONAL BORDER HAVE BEGUN TO INCREASE IN INTENSITY...WITH A LEFT SPLIT NOTED NW OF LK CHAMPLAIN AROUND 1815Z. A STRONGER CELL WITH ROTATION IS CURRENTLY /AS OF 1915Z/ SHIFTING INTO ST LAWRENCE COUNTY. STEEP MID-LEVEL LAPSE RATES PROGRESSING EWD AND WELL ABOVE NORMAL SURFACE TEMPERATURES ARE CONTRIBUTING TO MODERATE INSTABILITY ACROSS THE WW AREA...WITH DEEP LAYER WINDS STRENGTHENING AROUND THE BASE OF A HUDSON BAY TROUGH. SEVERE STORMS WILL CONTINUE TO GRADUALLY PROGRESS SWD ATTENDANT TO A COLD FRONT...WITH MAINTAINED INTENSITY. ..HURLBUT.. 07/17/2012 ATTN...WFO...GYX...BOX...BTV...ALY...BGM...BUF... LAT...LON 43457625 44167623 44857529 44967487 45037263 45017147 45287106 44997073 44327068 43827052 43317104 43067190 42887449 43107591 43457625