MESOSCALE DISCUSSION 2617 NWS STORM PREDICTION CENTER NORMAN OK 1120 PM CST SUN DEC 14 2003 AREAS AFFECTED...NERN NY ACROSS NRN NEW ENGLAND CONCERNING...HEAVY SNOW VALID 150520Z - 151115Z EXTREME DEEP LAYER ASCENT AND MOISTURE TRANSPORT INTO FAVORABLE MID LEVEL THERMODYNAMIC ZONE FOR DENDRITIC SNOW CRYSTAL GROWTH WILL CONTINUE TO PRODUCE COPIOUS SNOWFALL AMOUNTS ACROSS PORTIONS OF NERN NY AND NRN NEW ENGLAND THROUGH DAYBREAK. SNOWFALL RATES FROM THE NRN ADIRONDACKS ACROSS THE NRN GREEN AND WHITE MOUNTAINS EWD ACROSS MUCH OF MAINE WILL BE AROUND 1-2 INCHES PER HOUR WITH POCKETS OF MORE THAT 2 INCHES AN HOUR LIKELY...ESPECIALLY FROM NRN NH INTO MAINE. PARTS OF ERN/NERN VT MAY SEE SOMEWHAT LOWER SNOWFALL RATES DUE TO MID LEVEL DRY AIR INTRUSION AND SNOW SHADOW EFFECT FROM THE WHITE MOUNTAINS. 997MB SURFACE LOW WAS LOCATED NEAR SANDY HOOK NJ AT 15/05Z AND WILL TRACK TO NEAR CAPE COD THROUGH 15/12Z WHILE DEEPENING AT 1-3MB PER HOUR. 18Z RUN OF THE ETA WAS VERY ACCURATE WITH SHORT-TERM QPF AMOUNTS ACROSS NERN NY SHOWING 0.20-0.30 INCHES PER HOUR POSSIBLE ACROSS THE ADIRONDACKS. IT APPEARS THESE QPF RATES...AMOUNTING TO 2-3 INCHES OF SNOW PER HOUR...WILL VERIFY QUITE WELL BASED ON SLK OBS AND RADAR IMAGERY DURING THE EVENING. OVER THE NEXT 3-6 HOURS...LATEST ETA AND NCEP ENSEMBLE FCSTS INDICATE THAT THE AXIS OF STRONGEST 600-500MB FRONTOGENESIS... CORRESPONDING TO THE BAND OF HEAVIEST SNOW...WILL SHIFT FROM NERN NY ACROSS SRN QUEBEC AND INTO MAINE AND NRN NH. MEANWHILE...AS MID LEVEL CYCLOGENESIS OVER ERN NY RESULTS IN A CLOSED LOW FORMING AROUND 700MB...WRAPAROUND ASCENT WITHIN THE COMMA HEAD SHOULD KEEP MODERATE TO HEAVY SNOW GOING ACROSS THE NRN CHAMPLAIN VALLEY AND THE SPINE OF THE GREEN MOUNTAINS FOR SEVERAL MORE HOURS. AS THE LOW DEEPENS AND SURFACE PRESSURE GRADIENT TIGHTENS THROUGH THE REST OF THE NIGHT...BLOWING AND DRIFTING SNOW WILL LIKELY INCREASE...ESPECIALLY ACROSS THE HIGHER ELEVATIONS. ..CARBIN.. 12/15/2003 ATTN...WFO...CAR...GYX...BTV...ALY... 44956748 44117035 43597122 44477168 44417218 43647258 43537314 43947354 43787505 44447503 44787447 45307342 45957176 46597028 46736916 46836744
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