[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 301301
SWOMCD
SPC MCD 301301 
CAZ000-301700-

MESOSCALE DISCUSSION 2592
NWS STORM PREDICTION CENTER NORMAN OK
0701 AM CST THU DEC 30 2004

AREAS AFFECTED...CENTRAL/NRN SIERRA MTNS AND FAR NRN MTNS OF CA

CONCERNING...HEAVY SNOW 

VALID 301301Z - 301700Z

VERY HEAVY SNOW...WITH RATES OF 2"/HR...EXPECTED ACROSS THE CENTRAL
SIERRA MTNS THROUGH 18Z WITH SNOW LEVELS HOLDING AROUND 4000 FT.
SNOW WILL BECOME INTERMITTENT AND SHOWERY ACROSS THE MTNS OF FAR NRN
CA WITH SNOW LEVELS DROPPING TO 2500 FT BY 18Z.

AT 1230Z...MOSAIC RADAR IMAGERY SHOWS THE PRIMARY FRONTAL
PRECIPITATION BAND EXTENDING FROM SFO NEWD TO BLU AND INTO THE NRN
SIERRA MTNS...WITH EMBEDDED CONVECTIVE PRECIPITATION ASSOCIATED WITH
STEEP MID-LEVEL LAPSE RATES. MODERATE TO HVY SNOW HAS BEEN OBSERVED
AT BLUE CANYON SINCE 0530Z. VERY STRONG WLY TO SWLY FLOW IS EVIDENT
ON 12Z OAK SOUNDING...WITH 50KTS AT 700MB AND 90KTS AT 500MB. DEEP
LAYER SATURATION AND PRECIPITABLE WATER AROUND 0.75" SUGGEST
CONTINUED STRONG AND MOIST UPSLOPE FLOW...PROPAGATING SLOWLY SWD
INTO THE CENTRAL SIERRA MTNS THROUGH 18Z. SNOW RATES OF 2"/HR APPEAR
LIKELY WITH THIS PRIMARY AXIS OF PRECIPITATION INTO EARLY
AFTERNOON...WITH SNOW LEVELS HOLDING AROUND 4000 FT PER RUC FORECAST
SOUNDINGS.

PRECIPITATION SHOULD BECOME LIGHTER AND MORE SHOWERY ACROSS THE MTNS
OF FAR NRN CA AS COLD ADVECTION REGIME ADVECTS INLAND BEHIND PRIMARY
PRECIPITATION BAND. RUC SOUNDINGS BY 18Z INDICATE SNOW LEVELS AS LOW
AS 2500FT IN MT SHASTA VICINITY WITH SOME MINIMAL CAPE AROUND 100
J/KG WHICH WILL BE CONDUCIVE FOR CONVECTIVE SNOW SHOWERS AND
CONTINUED ISOLATED LIGHTNING STRIKES IN VICINITY OF THE COASTAL
RANGES. DESPITE OVERALL DECREASING SNOW RATES...BURSTS OF HEAVY SNOW
WILL REMAIN POSSIBLE THROUGH 18Z ASSOCIATED WITH LOW-TOPPED
CONVECTIVE CELLS.

..BANACOS.. 12/30/2004

...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...REV...HNX...MFR...STO...EKA...

39212109 38752083 38472067 38122040 37682003 37771917
38751994 39752029 40802077 41382112 41752138 41882200
41842280 41472343 41142356 40522343 40592290 41062255
41172226 41102191 40842167 

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