MESOSCALE DISCUSSION 2214
   NWS STORM PREDICTION CENTER NORMAN OK
   1255 AM CST THU DEC 13 2007
   
   AREAS AFFECTED...NRN OH...WRN/SCENTRAL PA...FAR NRN WV/WRN MARYLAND
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 130655Z - 131230Z
   
   A MIX OF FREEZING RAIN/SLEET AND MODERATE SNOW WILL DEVELOP NWD
   ACROSS THE AREA THROUGH 12Z. HRLY ACCUMULATIONS RATES UP TO 0.05
   INCH LIQUID WILL BE POSSIBLE...ESPECIALLY TOWARDS 12Z.
   
   LATEST RADAR MOSAIC SHOWS A BROAD AREA OF RAIN MOVING NEWD THROUGH
   THE OHIO VALLEY. AT 06Z SFC ANALYSIS SHOWS THE SFC FREEZING LINE
   EXTENDING FROM NEAR FINDLAY OH SEWD TO NEAR PIT AND INTO FAR WRN MD.
   STRENGTHENING LOW LEVEL WAA NOTED BY 1-2 MB/HR PRESSURE FALLS OVER
   CENTRAL IND/WRN OH /AIDED BY A 50 KT LOW LEVEL JET/ WILL SUPPORT THE
   CONTINUED RAPID NEWD DEVELOPMENT OF PRECIPITATION INTO AREAS THAT
   ARE BELOW FREEZING OVER THE NEXT 6 HRS. A FAIRLY DEEP DRY SUB-CLOUD
   AIRMASS FROM THE SFC TO NEAR 700 MB WILL INITIALLY LIMIT
   ACCUMULATIONS/RATES...BUT AS THE STRONGEST WAA OVERSPREADS THE
   REGION BETWEEN 09-12Z...SUFFICIENT SATURATION IS EXPECTED TO ENHANCE
   PRECIP RATES. DESPITE THE STRENGTH IN THE WAA...WET BULB EFFECTS
   SHOULD AID IN A SLOW SWD MOVEMENT OF THE LOCATION OF THE 06Z SFC
   FREEZING LINE. THE DEPTH OF THE ELEVATED WARM LAYER WILL BE GREATEST
   OVER MOST OF NRN OH...FAR NRN WV/SWRN PA AND WRN MD WHERE FREEZING
   RAIN IS EXPECTED TO BE THE PREDOMINANT P-TYPE THROUGH 12Z. FURTHER
   NE...OVER FAR NERN OH...MOST OF WRN AND SCENTRAL PA A MIX OF SLEET
   AND OR MODERATE SNOW IS EXPECTED BETWEEN 10-12Z WHERE THE ELEVATED
   WARM LAYER WILL BE MORE LIMITED OR NON-EXISTENT.
   
   ..CROSBIE.. 12/13/2007
   
   
   ...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...CTP...LWX...PBZ...RLX...CLE...ILN...IWX...
   
   41698085 41528283 41438419 40918480 40648448 40208254
   39918157 39658085 39428030 39137927 39177812 39337788
   39777768 40777848 41607970