MESOSCALE DISCUSSION 0189
   NWS STORM PREDICTION CENTER NORMAN OK
   0717 AM CST TUE MAR 16 2004
   
   AREAS AFFECTED...ERN PA...SERN NY...NRN NJ...WRN MA...WRN CT
   
   CONCERNING...HEAVY SNOW 
   
   VALID 161317Z - 161815Z
   
   SNOW WILL INCREASE IN COVERAGE AND INTENSITY THROUGH THE MORNING AND
   WILL CONTINUE INTO THE AFTERNOON. SNOW RATES OF 1 TO 2 INCHES/HOUR
   WILL BE POSSIBLE IN THIS AREA BY MID-LATE MORNING. SNOW MAY MIX WITH
   OR CHANGE TO SLEET ACROSS SE PA...NRN NJ AND SE NY BY LATE MORNING.
   
   A STRONG UPPER JET IS ROUNDING THE BASE OF OH VALLEY SHORTWAVE
   TROUGH. EXIT REGION OF THIS FEATURE IS BECOMING COUPLED WITH
   ENTRANCE REGION OF A DOWNSTREAM UPPER JET. WITHIN THE COUPLED JET
   STRUCTURE...LOW LEVEL JET WILL STRENGTHEN OVER THE NERN STATES WITH
   ATTENDANT STRONG FRONTOGENETIC FORCING...WARM ADVECTION AND
   ISENTROPIC ASCENT. THE STRONGEST ASCENT WILL EXTEND THROUGH THE
   LAYERS FAVORABLE FOR EFFICIENT SNOW CRYSTAL GROWTH. THE SNOW WILL
   CONTINUE TO EXPAND NEWD AND BECOME ORGANIZED IN BANDS. THE STRONG
   WARM ADVECTION MAY EVENTUALLY RESULT IN A NOSE OF WARM AIR ABOVE THE
   SUBFREEZING LAYER...WITH SNOW BECOMING MIXED WITH OR CHANGING TO
   SLEET ACROSS SRN PA THROUGH NRN NJ AND SE NY BY LATE MORNING OR
   EARLY AFTERNOON.
   
   ..DIAL.. 03/16/2004
   
   
   ATTN...WFO...BOX...OKX...ALY...PHI...BGM...CTP...
   
   41297276 40507416 40167687 42637605 42637319