"MAXIMUM SURFACE PRESSURE FALLS HAVE BECOME CENTERED ALONG WARM FRONT ACROSS COASTAL ME...DOWNSTREAM OF INTENSIFYING CYCLONE OVER MA BAY AT 16Z. AN INTENSE BAROCLINIC ZONE / CHARACTERIZED BY A SURFACE TEMPERATURE GRADIENT OF 45 F OVER 200 NM ACROSS ERN ME/ HAS RESULTED IN SUBSTANTIAL LOW-LEVEL WAA /INFERRED BY LARGE CYCLONIC HODOGRAPHS IN GRAY AND CARIBOU VAD PROFILERS/ AND SNOWFALL RATES REACHING 1 IN/HR /PER 16Z METARS IN BRUNSWICK ME AND PROVIDENCE RI/.WAA WILL STRENGTHEN AS THE LLJ INTENSIFIES THIS AFTERNOON WITH APPROACH OF SHORT WAVE TROUGH /CURRENTLY ROUNDING BASE OF LARGER-SCALE TROUGH OVER TN VALLEY/.
MORNING MODEL GUIDANCE QPF CORRESPONDINGLY INCREASE WITH BOTH GFS/NAM INDICATING PEAK AMOUNTS AROUND 0.50 IN FROM 21-00Z. ALTHOUGH SURFACE TEMPERATURES MAY WARM ABOVE FREEZING ACROSS IMMEDIATE COASTAL AREAS S OF THE US-1 CORRIDOR EAST OF ROCKLAND...HIGH SNOW TO LIQUID RATIOS FARTHER INLAND SHOULD RESULT IN SNOWFALL RATES OF 1 TO 2 IN/HR BECOMING PREVALENT."
..GRAMS/DARROW.. 01/18/2009
Graphic and discussion courtesy SPC.
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