Area Forecast Discussion
Issued by NWS Sacramento, CA

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956
FXUS66 KSTO 211226
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
426 AM PST Sat Jan 21 2017

.Synopsis...
Showers continue today, then the next in a series of winter storms
moves in tonight bringing heavier precipitation and strong winds.
Expect severe mountain travel impacts. Should see extended dry
period return next week.

&&

.Discussion...
Cold and unstable atmosphere will continue scattered showers
across the region today. A clap of thunder or two may accompany
some of the heavier showers. Snow levels will remain around 3-4K
ft. Breezy southerly winds will continue.

The next storm system will move through NorCal tonight into
Sunday with valley rainfall of 1 to 2 inches and mountain snow of
2 to 4 feet (locally higher amounts) and snow levels 3-4K feet.

Another round of strong gusty winds are anticipated with this
system. South to southeast winds will increase late this evening
beneath 55-65 kt 925 mb jet max. This will translate to 25-35 mph
winds with gusts to 55 mph over the Sacramento/northern San
Joaquin Valley (Redding to Modesto) into Sunday morning. Winds of
this magnitude will continue to pose a threat for tree damage and
power outages.

Front and deeper moisture are shunted south later Sunday for
diminishing precip and lighter winds. Some partial clearing across
the northern half of the Sacramento Valley Sunday afternoon may
pose a threat for some stronger thunderstorms. Showers continue
Monday.

Stacked surface/upper low progged to continue filling as it drops
southeastward Monday night into early Tuesday and will provide the
final chance for showers for NorCal through this period of wet
weather.

&&

.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)
Extended period of dry weather expected across the region during
the extended forecast period as models continue to show strong
ridging along the West Coast. Daytime highs start out slightly
below normal then climb to a little above normal by the end of the
week. Cool nights with fair skies allowing overnight lows to drop
to a little below normal.

&&

.AVIATION...
Mainly VFR TAF sites today except occasional MVFR/IFR ceilings
with passing showers. IFR ceilings and visibility over Sierra
Cascades. Deteriating conditions after about 06z tonight as next
frontal system pushes in with IFR/LIFR ceilings by 12z Sunday.
South winds 10 to 20 mph today increasing after 00z Sunday
reaching sustained 30 knots gusts to 50 knots by 12z Sunday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 4 AM PST Monday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

Winter Storm Warning from 7 PM this evening to 4 PM PST Sunday
for Mountains Southwestern Shasta County to Northern Lake County-
Shasta Lake Area / Northern Shasta County.

Wind Advisory from 10 PM this evening to 10 AM PST Sunday for
Carquinez Strait and Delta-Central Sacramento Valley-Clear
Lake/Southern Lake County-Motherlode-Mountains Southwestern
Shasta County to Northern Lake County-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Northern
San Joaquin Valley-Shasta Lake Area / Northern Shasta County-
Southern Sacramento Valley.

&&

$$



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