MESOSCALE DISCUSSION 2265
   NWS STORM PREDICTION CENTER NORMAN OK
   0558 AM CST THU DEC 05 2002
   
   AREAS AFFECTED...ERN PA...NRN NJ...SERN NY AND PARTS OF SRN CT
   
   CONCERNING...HEAVY SNOW
   
   VALID 051158Z - 051800Z
   
   SNOW RATES ARE EXPECTED TO INCREASE TO LOCALLY IN EXCESS OF 1 IN
   PER HOUR FROM ERN PA THROUGH SERN NY AND PART OF SRN NEW ENGLAND.
   THE INCREASE IS EXPECTED TO OCCUR AFTER 13Z OVER THE WRN PORTIONS
   
   OF THE AREA AND AFTER 15Z OVER ERN PORTIONS.
   
   THE LATEST SURFACE ANALYSIS SHOWS A SURFACE LOW NEAR CAPE
   HATTERAS ON THE NC OUTER BANKS WITH A WARM FRONT EXTENDING EWD
   INTO THE ATLANTIC. RATHER LARGE PRESSURE FALLS EXIST NEAR AND NE
   OF THE LOW. A SHORTWAVE TROUGH CURRENTLY NEAR THE SRN
   APPALACHIANS WILL CONTINUE NEWD AND APPROACH THE MID ATLANTIC
   REGION BY MID-DAY. LARGE SCALE ASCENT ASSOCIATED WITH THIS
   FEATURE WILL RESULT IN DEEPENING OF THE SURFACE LOW AS IT LIFTS
   NWD ALONG THE COAST TOWARD SRN NEW ENGLAND. AS THE SHORTWAVE
   TROUGH CONTINUES NEWD AND THE LOW DEEPENS...A SECONDARY LOW LEVEL
   JET WILL INTENSIFY JUST E OF THE LOW CENTER. THIS WILL ENHANCE
   NWD TRANSPORT OF MOISTURE FROM THE WRN ATLANTIC AS WELL AS MID
   LEVEL ASCENT ALONG ERN PART OF PRE-EXISTING DEFORMATION ZONE
   CURRENTLY EXTENDING FROM THE OH VALLEY EWD INTO SRN NEW ENGLAND.
   WITH A DEEP LAYER OF COLD AIR WELL ENTRENCHED OVER THE
   AREA...PTYPE IS EXPECTED TO BE MOSTLY ALL SNOW WITH RATES IN
   EXCESS OF 1 INCH PER HOUR POSSIBLE ONCE VERTICAL MOTION INCREASES
   IN THE LAYER CRITICAL FOR RAPID ICE CRYSTAL GROWTH. SNOWFALL
   RATES MAY ALSO BE ENHANCED BY THE VERY COLD NATURE OF THE AIR
   WHICH SHOULD YIELD RELATIVELY HIGH FROZEN/LIQUID RATIOS.
   
   
   ..DIAL.. 12/05/2002
   
   
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