[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 171903
SWOMCD
SPC MCD 171903 
WAZ000-172330-

MESOSCALE DISCUSSION 0108
NWS STORM PREDICTION CENTER NORMAN OK
0103 PM CST MON JAN 17 2005

AREAS AFFECTED...INTERIOR WA

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 171903Z - 172330Z

FZRA EXPECTED TO CONTINUE IN MTN PASSES/ERN SLOPES OF CASCADES...
WITH 0.05 IN/HR LIQUID EQUIVALENTS AND SIGNIFICANT ICE ACCUMULATIONS
POSSIBLE...WHILE FZRA/SLEET SPREADS EWD INTO PORTIONS OF NE WA
MTNS/COLUMBIA BASIN THROUGH 00Z.

WSWLY PACIFIC JET/WARM CONVEYOR WILL CONTINUE TO STREAM VERY MOIST
AIRMASS /AS EVIDENT BY 1.08 IN PRECIP WATER IN 12Z UIL RAOB/ INTO
THE PACIFIC NORTHWEST THROUGH LATE AFTERNOON. AT 18Z...SURFACE
DIAGNOSTICS/MESONET OBSERVATIONS DEPICT SHALLOW COLD AIRMASS
REMAINING ENTRENCHED FROM THE COLUMBIA BASIN THROUGH THE ERN SLOPES
OF THE CASCADES ON PERIPHERY OF 1038 MB CNTRL/SRN ID HIGH PRESSURE.

AS HAS BEEN THE CASE THIS MORNING...15Z BASED RUC FCST SOUNDINGS
SUPPORT CONTINUANCE OF FZRA SCENARIO IN MTN PASS AREAS/ERN SLOPES OF
CASCADES WHERE SHALLOW SUB-FREEZING AIRMASS PERSISTS BENEATH
ENCROACHING ELEVATED WARM LAYER BASED AROUND 850 MB. FURTHER
EAST...A RELATIVELY LIGHTER MIX OF SLEET/FZRA EXPECTED TO EXPAND EWD
ACROSS PORTIONS OF THE NE WA MTNS/COLUMBIA BASIN THIS AFTERNOON
OWING TO 850-700 MB THETA-E ADVECTION/INCREASINGLY SATURATED
VERTICAL PROFILES.

..GUYER.. 01/17/2005

...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...OTX...PDT...SEW...

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