MESOSCALE DISCUSSION 0015
   NWS STORM PREDICTION CENTER NORMAN OK
   0543 PM CST WED JAN 14 2004
   
   AREAS AFFECTED...ERN PA/NJ/SERN NY/NRN MD/NRN DE
   
   CONCERNING...HEAVY SNOW 
   
   VALID 142343Z - 150545Z
   
   MESOSCALE BAND OF SNOW WITH HOURLY RATES OF 1 INCH/HOUR IS EXPECTED
   TO DEVELOP ESEWD ACROSS THE REGION THIS EVENING.
   
   LATEST MESOANALYSIS INDICATED PRIMARY SURFACE LOW OVER SERN MI WITH
   ATTENDANT WARM FRONT EXTENDING ESEWD THROUGH CNTRL LAKE ERIE AND
   ACROSS CNTRL PA. BROAD AREA OF 2-3MB/3HR PRESSURE FALLS E OF SURFACE
   LOW IS LIKELY INDICATIVE DEEP-LAYER ASCENT AHEAD OF VIGOROUS
   MID-LEVEL TROUGH DIVING SEWD OUT OF THE GREAT LAKES.
   
   LATEST MODEL GUIDANCE SUGGESTS THAT EVOLVING MESOSCALE BAND OF
   HEAVIER SNOW FROM SWRN LAKE ERIE EWD INTO CNTRL PA WILL SLOWLY
   DEVELOP ESEWD OVER THE NEXT 3-6 HOURS ACROSS ERN/SERN PA AND MUCH OF
   NJ. HERE...LARGE-SCALE ASCENT WILL BE AUGMENTED BY AGEOSTROPHIC
   RESPONSE TO MID-LEVEL FRONTOGENESIS REGION WHICH WILL DEVELOP
   GENERALLY EWD FROM SRN NY/NRN PA INTO SRN NEW ENGLAND THROUGH
   15/06Z. ALTHOUGH LOW-LEVEL AIRMASS REMAINS RELATIVELY DRY ACROSS ERN
   PA INTO NJ...RUC FORECAST SOUNDINGS INDICATE RAPID TOP-DOWN
   SATURATION WITH THE ONSET OF THIS INCREASED FORCING FOR ASCENT.
   MOREOVER...THESE SOUNDINGS ALSO INDICATE THE DEVELOPMENT OF AN
   ISOTHERMAL LAYER FROM 800-700MB WITH TEMPERATURES MARGINALLY COLD
   /I.E. -10 TO -12C/ FOR DENDRITIC SNOW CRYSTAL GROWTH...WHICH SHOULD
   ENHANCE SNOWFALL RATES.
   
   ..MEAD.. 01/14/2004
   
   
   ATTN...WFO...OKX...PHI...BGM...CTP...LWX...
   
   41007767 41287666 41127541 40387319 39487351 38937424
   39537625 40227797