MESOSCALE DISCUSSION 0020
   NWS STORM PREDICTION CENTER NORMAN OK
   0417 PM CST TUE JAN 06 2009
   
   AREAS AFFECTED...CENTRAL AND WESTERN PA...EXTREME EASTERN OH...FAR
   NORTHERN MD
   
   CONCERNING...FREEZING RAIN 
   
   VALID 062217Z - 070215Z
   
   FRZ RAIN IS EXPECTED TO INTENSIFY ACROSS CENTRAL AND WESTERN PA
   THROUGH 00Z...WITH RATES UP TO 0.05 IN/HR DURING THE
   EVENING...INCREASING TO 0.10 IN/HR TONIGHT.
   
   WV IMAGERY DEPICTS A PLUME OF MOISTURE ADVANCING TOWARDS THE
   NORTHEASTERN STATES...INDICATIVE OF INCREASING LARGE SCALE ASCENT.
   THIS WILL SUPPORT CONTINUED STRENGTHENING OF LOW LVL WAA REGIME
   /EVIDENT BY STRONGLY VEERING WIND PROFILE IN PBF VAD WIND
   PROFILE/...YIELDING AN INTENSIFICATION OF PRECIPITATION OVER PA. 22Z
   SURFACE OBS SHOW AN AXIS OF HIGH PRESSURE EXTENDING SOUTH FROM NEW
   ENGLAND INTO VA...WHICH WILL AID IN MAINTAINING SUBFREEZING
   TEMPERATURES ACROSS THE REGION. ADDITIONAL MOISTENING AND COOLING
   WILL OCCUR AS INTENSIFYING PRECIPITATION FALLS THROUGH A SLIGHTLY
   SUBSATURATED LOW LVL AIRMASS. PROMINENT ELEVATED WARM NOSE
   ASSOCIATED WITH WAA IN THE 850-700 MB LAYER WILL SUPPORT THE
   OCCURRENCE OF FRZ RAIN...WITH RATES OF 0.05-0.10 IN/HR LIKELY.
   
   ..GARNER/HURLBUT.. 01/06/2009
   
   
   ...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...PHI...BGM...CTP...LWX...PBZ...CLE...
   
   LAT...LON   41088080 41318067 41588034 41747970 41757835 41607693
               41247611 40767581 40227580 39627648 39647794 39687901
               39878067 40938083 41088080