[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 311857
SWOMCD
SPC MCD 311857 
UTZ000-WYZ000-IDZ000-NVZ000-CAZ000-312300-

MESOSCALE DISCUSSION 2598
NWS STORM PREDICTION CENTER NORMAN OK
1257 PM CST FRI DEC 31 2004

AREAS AFFECTED...CENTRAL/SRN SIERRA NV NEWD INTO NRN UT/SERN ID

CONCERNING...HEAVY SNOW 

VALID 311857Z - 312300Z

HVY SNOW WILL COME TO AN END BY 20Z OVER THE CENTRAL/SRN SIERRA
NEVADA...WHILE DEVELOPING NEWD INTO CENTRAL/ECENTRAL NV. SNOWFALL
RATES FROM 1-2 IN/HR WILL BE POSSIBLE FOR A 2-3 HR PERIOD ACROSS
CENTRAL/NERN NV THROUGH 00Z. SNOWFALL SHOULD INCREASE IN INTENSITY
OVER THE NRN WASATCH UT AND THE CARIBOU HIGHLANDS OF SERN ID BETWEEN
21-00Z WITH HRLY RATES OVER 1 IN/HR BY 01Z. ADDITIONALLY...STRONG
WINDS IN EXCESS OF 40 MPH WILL PRODUCE CONSIDERABLE BLOWING AND
DRIFTING OF SNOW IN THE HIGHEST ELEVATIONS.

UPPER VORT MAX OVER THE CENTRAL SAN JOAQUIN VALLEY OF CA WILL
CONTINUE TO SHIFT NEWD ACROSS CENTRAL/NERN NV THROUGH 00Z. 2+ IN/HR
HVY SNOWFALL WILL COME TO AN END OVER THE CENTRAL/SRN SIERRA WITH
THE DEPARTURE OF THE UPPER VORT CENTER. STEEP MID LEVEL LAPSE RATES
FROM 7-7.5 DEG C/KM EVIDENT ON THE 12Z OAK SOUNDING AND RECENT VIS
IMAGERY WILL CONTINUE TO SUPPORT CONVECTIVE SNOWFALL RATES FROM 1-2
IN/HR AS THIS VORT CENTER PROGRESSES INTO CENTRAL/NERN NV ALONG
PREEXISTING MID LEVEL BAROCLINIC ZONE. PROGRESSIVE NATURE OF THE
UPPER FEATURES SUGGEST THAT HEAVIEST SNOW SHOULD ONLY LAST FOR 2-3
HOURS AT ANY LOCATION OVER THIS REGION. PER ELKO VWP DATA UPSLOPE
FLOW WILL BE MAXIMIZED ON SWLY FACING SLOPES OF RANGES ACROSS NV.
FARTHER NE ACROSS NRN UT/SERN ID...LOW LEVEL SWLY FLOW WILL CONTINUE
TO INCREASE WITH APPROACHING TROUGH. SNOW LEVELS INITIALLY STARTING
OUT AROUND 5-5.5 KFT THIS AFTERNOON BUT SHOULD LOWER QUICKLY WHEN
STRONGER FRONTAL DYNAMICS MOVE INTO THE REGION AFTER 00Z. IN
ADDITION THE HEAVIEST SNOWFALL OVER NRN UT/SERN ID WILL LIKELY BE
DURING THIS TIME..WHEN MAIN UPPER DEFORMATION ZONE AND FRONTOGENETIC
FORCING IN THE 700-600 MB LAYER COMBINES WITH INCREASING WLY LOW
LEVEL UPSLOPE FLOW.

..CROSBIE.. 12/31/2004

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A 
SCHEDULED BASIS...FOUR TIMES A DAY...BETWEEN 00-01 UTC...
06-07 UTC...12-13 UTC...AND 18-19 UTC AS SIGNIFICANT SHORT
RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
USED FROM DECEMBER 1 THROUGH FEBRUARY 28.

ATTN...WFO...RIW...SLC...PIH...VEF...BOI...LKN...REV...HNX...

42991258 40251699 39161816 38251956 37361924 36981825
37551659 38931395 40061167 40681098 43191117 

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