Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 271720
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
920 AM PST Thu Nov 27 2014

.Synopsis...
Mild Thanksgiving will give way to a wet Friday and weekend.
Slick roads and snow above 6000 feet (where from 6 to 12 inches of
snow is possible late Friday into Sunday morning) may cause travel delays.
Unfortunately a lot of uncertainty remains with second storm
system arriving sometime in the Monday through Wednesday time
frame.

&&

.Discussion...
Mostly sunny Thanksgiving day with some mid and high clouds
moving through the area under weak ridge. Temperatures will peak in
the mid to upper 60s in the valley and upper 40s to low 60s in the
mountains this afternoon, which is about 6 to 12 degrees above
normal. Friday temperatures will cool with highs in the upper 50s
to mid 60s in the Valley and 40s to mid 50s in the mountains as
an upper level trough approaches the area. Precipitation will
start moving into the Coastal range and the Northern Sacramento
Valley Friday by noon and spread southeast to around the I-80
corridor in the evening and in the Northern San Joaquin Valley
Saturday morning as the jet and 1.3 in Precipitatable water plume
sag south. Precipitation is expected to continue during the day
Saturday with some weak upward motion and moisture. Saturday will
be cooler with highs in the low to mid 50s in the Valley and 30s
to mid 40s in the mountains. Snow levels will be around 7500 ft
(near pass level in the Sierra) Friday evening and drop down to
around 5500 ft Saturday morning. Several inches of snow are
possible above 6000 ft by Saturday evening. Rainfall amounts are
expected to be around a quarter to three quarters in the Valley and
generally around an inch to an inch and a half in the mountains by
Saturday evening. Precipitation will probably continue at least at
times on Sunday but there is more uncertainty in the amounts.
There is variability in the models with the ECMWF with the
strongest wave but all have a little lift and some moisture for
periods of precipitation.


.Extended Discussion (Monday through Thursday)

As noted from day shift yesterday...confidence unfortunately
decreasing with next system originally thought to be stronger of
these 2 systems. This still may be the case as it seems likely
upper low will eventually shift into CA but timing of that system
to arrive continues to be troublesome. GFS is deeper and further
east with the upper low Monday afternoon and night bringing
moisture into northern valley with ECMWF also unsettled but with
different solution keeping upper low further west.

Tuesday and Tuesday night...GFS moves the upper low to the coast
and into central CA which would bring some nice moisture to the area
(with parallel even wetter again)...with ECMWF again further west
delaying the arrival of it until Wednesday and Wednesday night. At
this time seems best message is that we should get another round
of rain...but when is unsure at this time. Either scenario though
doesn`t look to be much of an impact. Rasch


&&

.Aviation...

BKN-OVC high clouds today. Patchy IFR/LIFR fog will persist
through about 18z today across portions of the Central Valley,
otherwise VFR conditions with generally light winds expected
across TAF sites Thanksgiving. Local MVFR/IFR conditions are possible around
Sacramento and Stockton aft 10z until 18z Friday. Lowering
ceilings and precipitation possible with areas of MVFR conditions by Friday
afternoon around KRDD and KRBL.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$






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