MESOSCALE DISCUSSION 2510
   NWS STORM PREDICTION CENTER NORMAN OK
   1018 PM CST MON DEC 06 2004
   
   AREAS AFFECTED...SWRN ORE AND NRN CA
   
   CONCERNING...HEAVY SNOW AND NEAR BLIZZARD CONDITIONS 
   
   VALID 070418Z - 071015Z
   
   HVY SNOW WITH HOURLY RATES AT TIME OVER 3 INCHES WILL BEGIN TO
   DIMINISH OVER SWRN ORE AND THE SHASTA/SISKYOU MTNS AND THE COASTAL
   RANGE OF FAR NRN CA BETWEEN 05-08Z...WHILE DEVELOPING SEWD INTO THE
   NRN/CENTRAL SIERRA NEVADA THROUGH 11Z. IN ADDITION...STRONG WINDS
   FROM 30-40 MPH WILL BE LIKELY IN THE HIGHEST EXPOSED MTN PASSES
   LEADING TO NEAR BLIZZARD CONDITIONS.
   
   HVY SNOW AIDED BY STRONG OROGRAPHIC ASCENT AND POTENT WARM ADVECTION
   PATTERN WITH 70 KTS IN THE 1-3 KM LAYER NOTED ON RECENT VWP FROM
   MEDFORD WILL BEGIN TO DIMINISH OVER SWRN ORE/FAR NRN CA BETWEEN
   06-09Z AS UPPER TROUGH AND ASSOCIATED ASCENT SHIFTS SEWD OUT OF THE
   AREA. STRENGTH OF THE LOW-MID LEVEL ASCENT HAS LEAD TO OBSERVED
   HOURLY RATES FROM 3-4 INCHES IN WRN/SWRN FACING SLOPES DURING THE
   LAST 3-4 HOURS. AS THE UPPER TROUGH CONTINUES TO ADVANCE INTO SWRN
   ORE/NWRN CA...HVY SNOW WILL DEVELOP SEWD INTO THE NRN AND CENTRAL
   SIERRA THROUGH 12Z. SNOW LEVELS ARE RANGING FROM AROUND 3500 FT IN
   THE NRN SIERRA TO AROUND 5500 FT IN THE CENTRAL SIERRA NEVADA BASED
   RECENT ON RAWS/ASOS OBS. DESPITE THE STRENGTH OF LOW-MID LEVEL
   WAA...OVERALL STRONG DYNAMIC LIFT SHOULD COUNTERACT LOW LEVEL
   WARMING LIMITING ANY APPRECIABLE CHANGE IN THE SNOW LEVELS
   OVERNIGHT. CONTINUED STRONG SSWLY LOW-MID LEVEL FLOW WILL FAVOR THE
   HIGHEST SNOWFALL RATES FROM 2-3 INCHES PER HOUR OVER NW-SE MTNS IN
   THE LASSEN PARK REGION/NRN SIERRA NEVADA...WITH SLIGHTLY LESSER
   RATES EXPECTED IN THE CENTRAL SIERRA NEVADA WHERE FLOW WILL BE MORE
   PARALLEL TO THE RANGE.
   
   ..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...REV...HNX...MFR...STO...EKA...
   
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