Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 011014
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
314 AM PDT Sat Nov 1 2014

.Synopsis...
Lingering showers and possibly a few thunderstorms will continue
today and diminish this evening. Drier and milder weather is
expected for much of next week.

&&

.Discussion...
Satellite imagery early this morning shows an unseasonably deep
upper level trough lined up along the coast. Its associated
frontal system is running nearly parallel to the Sierra Nevada
this morning, with a solid band of precipitation generally along
the eastern Central Valley up into the mountains. Embedded heavier
showers generated a few lightning strikes early this morning from
Rocklin north to Oroville. Snow levels have dropped below trans-
Sierra passes, but we won`t have a good gage on snowfall totals
until later this morning. Storm total precipitation numbers as of
this writing range from a few tenths across parts of the Valley to
over an inch over some favored locations of the Northern Sierra.

Precipitation is expected to continue through the morning and into
the afternoon. The upper low will move overhead later this
morning, and shift eastward this afternoon. With partial clearing
likely across portions of the forecast area, and a vort on the
backside of the upper trough, some destabilization of the
atmosphere is likely this afternoon. As such, we`ve included
mention of a slight chance of thunderstorms this afternoon across
much of the Valley, Sierra Foothills, and Coastal Ranges.

Precipitation should be on the decrease this evening as the
atmosphere stabilizes, and as subsidence increases behind the
upper trough. We may see some patchy fog development occur
Saturday night and Sunday morning across some interior, wind-
sheltered Valleys as skies clear.

Some breezy north winds are likely to develop Sunday. However,
pressure gradients aren`t forecast to tighten too drastically, nor
will there be much cold advection to enhance winds. Thus, breezy
winds are likely to remain locally confined.

A modest warming trend is in store for early next week as high
pressure builds in from the eastern Pacific. Expect temperatures
to reach near-normal levels Monday and Tuesday.

Dang


.Extended Discussion (Wednesday through Saturday)

High pressure ridge will remain the dominant feature across the
forecast area through the extended period. Look for highs to be
around 5 degrees warmer than normal. Extended models do move a
weak system over the north end of the ridge and into the Pacific
Northwest on Thursday according to the ECMWF. On the other hand,
the GFS and GEM are a bit slower (12-18 hrs) and weaker with this
wave. We compromised with the models and meshed with our
neighboring coastal offices on introduced and slight chance of
precip over the Coastal Mountains Wed night into Thu night.

JClapp/Dang


&&

.Aviation...

Deep upper trough moving across NORCAL today. For the Sierra
Cascade range...MVFR/IFR in showers with snow above 050. Showers
ending after 06z Sunday. For the coastal range and central valley
sct IFR/LIFR cigs and visibility with isolated showers and
thunderstorms through 00z. Sct IFR/showers through about 06z then
clearing. Otherwise VFR. Some IFR in patchy fog locally near the
delta/Southern SAc and Northern San Joaquin valleys after 06z Sunday.
South to southwest winds to 15 knots today becoming northerly
tonight.

&&

.STO Watches/Warnings/Advisories...
winter weather advisory until 2 pm pdt this afternoon above 6000
feet in the western plumas county/lassen park.

winter storm warning until 2 pm pdt this afternoon above 6000
feet in the west slope northern sierra nevada.

&&

$$








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