MESOSCALE DISCUSSION 2514
   NWS STORM PREDICTION CENTER NORMAN OK
   0555 AM CST TUE DEC 07 2004
   
   AREAS AFFECTED...CENTRAL/SRN SIERRA NEVADA ABOVE 5000 FT
   
   CONCERNING...HEAVY SNOW 
   
   VALID 071155Z - 071800Z
   
   HVY SNOW WITH HRLY ACCUMULATIONS AROUND 2 INCHES WILL CONTINUE TO
   SPREAD SWD INTO SRN SIERRA NEVADA THROUGH 18Z...WITH DIMINISHING
   TRENDS EXPECTED OVER THE CENTRAL SIERRA NEVADA DURING THE SAME TIME
   FRAME.
   
   LATEST IR IMAGERY SHOWS REINVIGORATION OF COOLING CLOUD TOPS OVER
   CENTRAL CA...DUE TO STRENGTHENING UPPER FORCING LIKELY A RESULT OF A
   SECONDARY JET MAX ROTATING INTO THE REGION AND ENHANCING THE LOW
   LEVEL FRONTOGENETIC CIRCULATION. AS THE BAROCLINIC ZONE CONTINUES TO
   SLIDE SEWD THROUGH THE SRN SIERRA...EXPECT A RELAXING OF HVY SNOW
   OVER THE CENTRAL SIERRA NEVADA THROUGH THE LATE MORNING AS FORCING
   IN THE DENDRITIC SNOW GROWTH LAYER WEAKENS. HOWEVER...SNOW SHOULD
   REMAIN MODERATE OVER THE WRN SLOPES THROUGH THE EARLY AFTERNOON
   BEHIND THE MAIN FRONTAL ZONE...AS STRONG WLY LOW LEVEL FLOW
   MAINTAINS STRONG OROGRAPHIC ASCENT. SNOW LEVELS CURRENTLY ARE
   RUNNING FROM 4500 FT IN THE CENTRAL SIERRA TO AROUND 5500 FT IN THE
   SRN SIERRA. IT IS ANTICIPATED THAT THE SNOW LEVELS WILL FALL SLOWLY
   OR REMAIN NEAR THE PRESENT VALUES IN THE SRN SIERRA NEVADA GIVEN THE
   STRENGTH OF THE VERTICAL MOTION AND LOW LEVEL SELY FLOW MAINTAINING
   WEAK CAA IN THE NEAR SFC LAYER AHEAD OF THE FRONTAL BOUNDARY.
   
   ..CROSBIE.. 12/07/2004
   
   
   ...NOTICE...
   SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A 
   SCHEDULED BASIS...FOUR TIMES A DAY...BETWEEN 05-06 UTC...
   11-12 UTC...17-18 UTC...AND 23-00 UTC AS SIGNIFICANT SHORT
   RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
   USED FROM DECEMBER 1 THROUGH FEBRUARY 28 TO ALLOW PARTNERS
   AND USERS TO BETTER ANTICIPATE THE TIMING OF SPC WINTER WEATHER
   MESOSCALE DISCUSSIONS.
   
   ATTN...WFO...VEF...REV...HNX...STO...
   
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