MESOSCALE DISCUSSION 0438
   NWS STORM PREDICTION CENTER NORMAN OK
   0853 PM CDT WED APR 04 2007
   
   AREAS AFFECTED...NRN NH AND MAINE
   
   CONCERNING...HEAVY SNOW 
   
   VALID 050153Z - 050800Z
   
   SNOWFALL RATES WILL GRADUALLY INCREASE TO MAX HRLY RATES OF 1-1.5
   IN...PRIMARILY AFTER 06Z FROM PARTS OF NRN NH INTO MAINE.  THOUGH
   MDT-HVY SNOWS WILL OCCUR OVER MOST OF REGION FOR A TIME
   TONIGHT...HEAVIEST RATES SHOULD EVOLVE ALONG THE ERN SLOPES OF THE
   WHITE MOUNTAINS IN NH NEWD INTO THE WRN/NRN MAINE MOUNTAIN RANGES NW
   OF I-95.
   
   H5 ANALYSIS SHOWS NOSE OF A 95 KT JET NOSING NEWD ACROSS THE
   MID-ATLANTIC WITH STRONG ASCENT SPREADING DOWNSTREAM INTO SRN NEW
   ENGLAND THIS EVE.  LOW-LEVEL FLOW WAS RESPONDING WITH 1-2 KM SSELY
   FLOW AT TAUNTON OF 40-45 KTS.  THIS SHOULD INCREASE TO NEARLY 60 KTS
   AFTER 06Z AT THE POINT WHERE CYCLOGENESIS IS MAXIMIZED... GENERALLY
   IN THE 06-12Z TIME FRAME.  BEGINNING OF THE HEAVIER PCPN MAY ALREADY
   BE EVOLVING DOWNSTREAM ACROSS SRN NEW ENGLAND COINCIDENT WITH
   COOLING CLOUD TOPS PER IR IMAGERY.  
   
   SFC PRESSURE FALL AXIS ACROSS SERN MA SUGGEST THAT THE LOW JUST SE
   OF LONG ISLAND AT 01Z WILL TRACK ALONG THE COASTAL FRONT AND  INTO
   THE GULF OF MAINE BY 09-12Z.  DEFORMATION ZONE NW OF THIS LOW WILL
   BECOME JUXTAPOSED WITH STRONG SELY UPSLOPE FLOW ALONG THE
   AFOREMENTIONED MOUNTAIN CHAINS...ENHANCING SNOWFALL RATES.  MOST
   FAVORABLE DENDRITIC GROWTH ZONE IS LIKELY TO REMAIN WEST OF THE
   REGION.  BUT...MAGNITUDE OF MOISTURE WRAPPING INTO THIS SYSTEM...
   10:1 SNOW RATIOS AND THE TIMING OF THE EVENT AT NIGHT WILL ALL
   COMPENSATE...RESULTING IN RATHER HEAVY SNOWFALL RATES.
   
   ..RACY.. 04/05/2007
   
   
   ATTN...WFO...CAR...GYX...
   
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