MESOSCALE DISCUSSION 2228
   NWS STORM PREDICTION CENTER NORMAN OK
   0643 PM CST SAT DEC 15 2007
   
   AREAS AFFECTED...FAR SRN NY...MUCH OF PA...WRN MD...NRN AND WRN
   VA...ERN WV
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 160043Z - 160645Z
   
   A MIX OF FREEZING RAIN...SLEET AND SNOW WILL INCREASE ACROSS THE
   AREA THROUGH THE EVENING. POCKETS OF SIGNIFICANT ICING WILL BE
   POSSIBLE...ALONG WITH MDT TO HEAVY SLEET.
   
   BROAD ZONE OF WARM ADVECTION PERSISTS AHEAD OF DEEPENING SURFACE LOW
   WITH INCREASING RADAR RETURNS MOVING NWD OUT OF WV/VA. SURFACE
   ANALYSIS SHOWS FREEZING LINE EXTENDS SWWD OUT OF ERN PA INTO THE ERN
   APPALACHIANS WITH COLD AIR DAMMING. MEANWHILE...00Z RNK SOUNDING
   SHOWS A FAVORABLE PROFILE FOR FREEZING RAIN AS DOES THE IAD SOUNDING
   GIVEN EXPECTED LOW LEVEL EVAPORATIVE COOLING. TO THE N...PROFILES
   FROM SOUTH CNTRL PA N WERE ENTIRELY BELOW FREEZING AS OF 00Z.
   
   CONTINUED ISENTROPIC LIFT WILL RESULT IN PRECIPITATION RATES
   INCREASING TO 0.05 - 0.10 IN/HR IN GENERAL. FREEZING RAIN WILL BE A
   PROBLEM MAINLY FROM FAR SRN PA...WRN MD SWD ALONG THE WV/VA BORDER
   TOWARD RNK. THE PREDOMINATE PRECIPITATION TYPE WILL BE SLEET...SOME
   HEAVY...ACROSS CNTRL PA. A CHANGE FROM MDT SNOW TO A MIXTURE OF
   SLEET AND SNOW WILL OCCUR OVER NRN PA INTO FAR SRN NY BY 06Z AS WARM
   NOSE NEAR 800 MB MIGRATES N.
   
   ..JEWELL.. 12/16/2007
   
   
   ...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...PHI...BGM...BUF...CTP...LWX...RNK...PBZ...RLX...CLE...
   
   41807583 39397664 38667807 37167982 36998050 37178110
   37638119 37848102 38148045 38497995 39007960 39397949
   40118012 40498091 40848095 42387978 42577797