MESOSCALE DISCUSSION 2613
   NWS STORM PREDICTION CENTER NORMAN OK
   0537 PM CST SUN DEC 14 2003
   
   AREAS AFFECTED...SERN NY/NRN NJ/SRN NEW ENGLAND
   
   CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 
   
   VALID 142337Z - 150430Z
   
   A NARROW AND COMPLEX PTYPE TRANSITION ZONE WILL GRADUALLY DEVELOP
   NWD ACROSS SERN NY AND SRN NEW ENGLAND...AND NWWD ACROSS SERN NEW
   ENGLAND OVER THE NEXT FEW HOURS AS A POWERFUL LOW LEVEL JET
   CONTINUES TO PUMP WARMER AIR AND ATLANTIC MOISTURE INLAND ATOP COLD
   SURFACE-BASED AIRMASS. WHILE RAIN SHOULD DEVELOP AT MOST COASTAL
   AREAS WITHIN 1-2 HOURS...SOME POCKETS OF FREEZING RAIN OR WET SNOW
   WILL STILL BE POSSIBLE JUST INLAND FROM THE COAST. A LITTLE FARTHER
   INLAND...SNOW WILL MIX WITH SLEET AND FREEZING RAIN...WITH SLEET AND
   FREEZING RAIN BECOMING MORE PREDOMINATE WITH TIME. SNOW WILL LIKELY
   REMAIN THE DOMINATE PTYPE NORTH OF A LINE FROM POU TO I90 AND ALONG
   AND NORTH OF I90 TO NW OF BOS THROUGH ABOUT 15/05Z....WITH A
   TRANSITION TO MIXED PRECIPITATION EVEN THIS FAR INLAND AFTER 05Z.
   
   LATEST RADAR COMPOSITE LOOP WAS SHOWING BREAKS IN THE PRECIPITATION
   SHIELD ACROSS SERN NY AND PORTIONS OF SRN NEW ENGLAND.
   HOWEVER...THIS TREND WILL LIKELY BE SHORT-LIVED AS HIGHER 
   REFLECTIVITY ECHOES WERE CONSOLIDATING OVER LONG ISLAND...AS WELL AS
   ERN PA. THUS...ANOTHER ROUND OF MODERATE TO HEAVY PRECIPITATION
   SHOULD SPREAD ACROSS THE REGION OVER THE NEXT FEW HOURS. LATEST
   SURFACE OBSERVATIONS SUGGEST THAT SURFACE FREEZING LINE HAS ONLY
   MADE IT INLAND AS FAR AS A HPN-PVD-FMH-BOS LINE AT 23Z/6PM EST.
   DESPITE THIS SLOW INLAND PENETRATION OF THE WARMER SURFACE AIR...
   INTENSE WARM AIR ADVECTION WAS OCCURRING ABOVE THE SURFACE AIDED BY
   70KT LOW LEVEL JET. EXPECT THE 850MB 0C ISOTHERM WILL MOVE ACROSS
   MUCH OF CT/RI AND SERN MA OVER THE NEXT FEW HOURS WHICH SHOULD
   RESULT IN A CHANGEOVER FROM SNOW IN MOST OF THESE AREAS TO RAIN NEAR
   THE COAST...AND SNOW MIXING WITH SLEET/FREEZING RAIN INLAND.
   
   ..CARBIN.. 12/14/2003
   
   
   ATTN...WFO...BOX...OKX...ALY...
   
   40937376 41157426 41547441 41847385 42217240 42377148
   42757092 42807068 41947076 41617096