MESOSCALE DISCUSSION 0023
   NWS STORM PREDICTION CENTER NORMAN OK
   1110 PM CST TUE JAN 06 2009
   
   AREAS AFFECTED...NORTHEAST/SRN NEW ENGLAND
   
   CONCERNING...FREEZING RAIN 
   
   VALID 070510Z - 070915Z
   
   ONGOING ICE STORM WILL GRADUALLY EXPAND NEWD OVERNIGHT. BY 12Z...THE
   TRANSITION BETWEEN SLEET AND FREEZING LINE SHOULD LIE ROUGHLY ALONG
   THE SRN SHORES OF LK ONTARIO TO NEAR THE ALB AND BOS METRO AREAS.
   WIDESPREAD FREEZING RAIN RATES OF 0.02 TO 0.10 IN/HR WILL
   CONTINUE...WITH THE MORE INTENSE RATES AND SIGNIFICANT ICE
   ACCUMULATIONS EXPECTED ACROSS ERN PA/NRN NJ/SERN NY/CT/RI. 
   
   RADAR/SATELLITE IMAGERY DEPICTS A LONG PLUME OF PRECIPITATION AND
   BAROCLINIC LEAF STRUCTURE EXTENDING FROM THE NORTHEAST TO CNTRL GULF
   COAST DOWNSTREAM OF POTENT SHORT WAVE TROUGH APPROACHING THE
   MID/LOWER MS RIVER VALLEY. AS CYCLOGENESIS ENSUES INVOF LK ERIE...A
   STRONG LLJ /60 KT AT 850 MB ALONG THE PIEDMONT AS SAMPLED BY 00Z FFC
   RAOB/...WILL LIKELY STRENGTHEN TO AROUND 75 KT BY 12Z AS IT SHIFTS
   NEWD. THIS WILL MAINTAIN/ENHANCE THE ALREADY ROBUST LOWER-LEVEL
   WARM/MOIST ADVECTION REGIME ACROSS THE NORTHEAST. LATEST NAM/NAMKF
   WERE TOO SLOW WITH THE LEADING EDGE OF MEASURABLE PRECIPITATION
   THROUGH 03Z...WITH THE GFS QPF APPEARING TO FIT CLOSER TO
   OBSERVATIONS. GIVEN THE EXPECTED STRENGTHENING OF LARGE-SCALE ASCENT
   AND RECENT RADAR TRENDS...THE GFS APPEARS CONSISTENT WITH INCREASING
   QPF VALUES TO AOA 0.25 IN BETWEEN 09-12Z FROM ERN PA TO CT/RI. 
   
   WITH SURFACE WINDS ORIENTED NEARLY PARALLEL TO THE WET-BULB FREEZING
   LINE...ONLY A SLOW NWD MOVEMENT OF THIS LINE IS EXPECTED GIVEN
   DOWNWARD SENSIBLE HEAT FLUX VIA PRECIPITATION FALLING FROM WARMER
   LAYER JUST ABOVE SURFACE. MODEL FORECASTS ADVECT THE WARM NOSE OF
   ABOVE-FREEZING TEMPERATURES ALOFT MUCH FARTHER NORTH. THIS SUGGESTS
   THAT THE AREAL COVERAGE OF FREEZING RAIN/SLEET WILL EXPAND NEWD WITH
   LITTLE CONTRACTION ALONG THE SRN EDGE.
   
   ..GRAMS.. 01/07/2009
   
   
   ...NOTICE...
   SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
   SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
   TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
   FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.
   
   ATTN...WFO...BOX...OKX...ALY...PHI...BGM...BUF...CTP...LWX...
   PBZ...
   
   LAT...LON   42327111 42727140 42897331 43087484 43387662 43467823
               43357898 42777891 42347946 41557951 41047889 40277794
               39587709 39917593 40347490 40647420 40867368 41207303
               41387208 41527155 41757118 42327111