MESOSCALE DISCUSSION 2418
   NWS STORM PREDICTION CENTER NORMAN OK
   1030 AM CST SUN NOV 21 2004
   
   AREAS AFFECTED...PARTS OF NCNTRL THROUGH NW AZ INTO SW UT
   
   CONCERNING...HEAVY SNOW 
   
   VALID 211630Z - 212230Z
   
   HEAVY SNOW WITH RATES LOCALLY TO 2-2.5 INCHES PER HOUR EXPECTED
   ACROSS PARTS OF NCNTRL THROUGH NW AZ AND INTO SW UT THROUGH THE
   AFTERNOON. SNOW ELEVATIONS WILL GENERALLY BE AOA 6000 FT EAST OF 
   A KINGMAN TO ST GEORGE LINE. SNOW ELEVATIONS WILL BE LOCALLY AOB
   5000 FT WEST OF THIS LINE BUT MAY RISE SLOWLY DURING THE DAY.
   
   THIS MORNING A BAROCLINIC ZONE EXTENDS FROM NWRN AZ NEWD THROUGH S
   CNTRL UT. THE UPPER LOW AND ASSOCIATED STRONG UPPER JET WILL DROP
   SSEWD THROUGH SRN CA AND INTO WRN AZ...MAINTAINING STRONG UPPER
   DIVERGENCE...FRONTOGENETIC AND Q-G FORCING IN VICINITY OF THIS
   BOUNDARY THROUGH THE AFTERNOON. STRONG SLY FLOW WILL PERSIST
   DOWNSTREAM FROM THE UPPER LOW THROUGH AZ...ENHANCING UPSLOPE FLOW
   OVER THE HIGHER TERRAIN ALONG AND N OF THE MOGOLLON RIM FROM NRN AZ
   INTO SRN UT. THE STRONG Q-G FORCING AND UPSLOPE FLOW WILL RESULT IN
   LOCALLY HEAVY SNOWFALL ESPECIALLY IN VICINITY OF BAROCLINIC ZONE
   FROM NRN AZ INTO SRN UT. STEEP MID LEVEL LAPSE RATES IN THE PRESENCE
   OF STRONG FORCING FOR MID LEVEL ASCENT WILL ALSO SUPPORT
   CONVECTIVELY ENHANCED SNOWFALL. THE STRONG SLY FLOW ASSOCIATED WITH
   THE UPPER LOW MAY CONTRIBUTE TO THE BAROCLINIC ZONE PIVOTING NWWD
   WITH TIME...AND SUGGESTS SNOW LEVELS OVER NW AZ MAY UNDERGO SOME
   INCREASE DURING THE AFTERNOON.
   
   ..DIAL.. 11/21/2004
   
   
   ATTN...WFO...FGZ...SLC...VEF...
   
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