MESOSCALE DISCUSSION 0174
   NWS STORM PREDICTION CENTER NORMAN OK
   1131 PM CST TUE FEB 19 2013
   
   AREAS AFFECTED...NRN MAINE
   
   CONCERNING...HEAVY SNOW 
   
   VALID 200531Z - 200930Z
   
   SUMMARY...SNOWFALL RATES UP TO 1 INCH/HR ARE PROBABLE ACROSS NRN
   MAINE TONIGHT.
   
   DISCUSSION...NEGATIVELY TILTED SHORTWAVE TROUGH IS PIVOTING NEWD
   ACROSS SRN NEW ENGLAND AS OF 0530Z. MEANWHILE...RELATIVELY MOIST SLY
   850 MB FLOW ASSOCIATED WITH A WARM CONVEYOR BELT IS SPREADING INTO
   MAINE. UPPER DIVERGENCE AND STRONG LARGE-SCALE ASCENT OVERSPREADING
   THIS MOIST SLY FLOW HAS RESULTED IN AN EXPANSIVE SHIELD OF
   PRECIPITATION MOVING NWD ACROSS COASTAL MAINE. MEANWHILE AT THE
   SURFACE...ELY WINDS ARE MAINTAINING A SUB-FREEZING AIRMASS ACROSS
   THE NRN HALF OF MAINE. AS THE PRECIPITATION SHIELD SPREADS N ACROSS
   THIS AIRMASS...SNOWFALL RATES OF 1 IN/HR WILL BECOME PROBABLE.
   SHORT-TERM MODEL GUIDANCE INDICATES HEAVY SNOW WILL OCCUR THROUGH
   12Z...AND THEN EXIT INTO CANADA BY MID MORNING.
   
   ..GARNER.. 02/20/2013
   
   
   ATTN...WFO...CAR...GYX...
   
   LAT...LON   47066762 45716744 45326799 45427044 45857058 47486925
               47066762