Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 202327
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
327 PM PST Fri Jan 20 2017



.Synopsis...
A series of winter storms over the weekend with rain, mountain
snow and strong winds. Expect mountain travel impacts...Winds
could become damaging at times. Should see extended dry period for
the middle to end of next week.

&&

.Discussion...
Cold and unstable atmosphere is swinging into NorCal late this
afternoon behind frontal system that passed through area around
noon. Showers and isolated thunderstorms will continue through
the evening in this environment...with a few heavier bursts of
snow over the mountains. Some of the storms may contain abundant
small hail. Snow levels have dropped as low as as 3000 feet...but
should generally remain between 3500-4000 feet.

The next storm system will swing through NorCal Saturday night
into Sunday with valley rainfall of 1 to 2 inches and mountain
snow of 2 to 3 feet and snow levels 3000-4000 feet. Another round
of gusty winds with speeds to 50 mph anticipated with this
system. South to southeast winds will increase around 10 pm under
55-65 kt 925 jet max. This will translate to 30-35 mph winds with
a few gusts to 50 mph over the Sacramento/San Joaquin valley
Redding to Modesto into mid-day Sunday. This type of wind will
likely down trees and power lines...especially those weakened by
earlier strong winds. Power outages will be possible Saturday
night and Sunday morning.

Upper low is progged to drop southeast over northern California
Monday. Moisture will be less with this system versus previous
storms. However...very cold air aloft with low snow levels will
optimize snow amounts and accumulating snow may be possible down
to 1500 feet. Valley thunderstorms may also be possible with small
hail and locally heavier rain amounts.

&&

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)

Extended period of dry weather expected across the region during
the extended forecast period as models continue to show strong
ridging developing along the West Coast. Cool nights and mild
days with this dry pattern.

&&

.AVIATION...

Improving conditions this evening for the valley as this system
pushes off to our east. Mainly VFR conditions expected these next
24 hours although reduced visibilities (MVFR) could occur tonight
especially if we see some clearing. A shower or two is possible
Saturday morning in the valley with widespread rain returning in
the evening. Strong southerly winds will return late Saturday
night into Sunday morning. Wilson


&&

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

Winter Weather Advisory until 4 PM PST this afternoon for
Mountains Southwestern Shasta County to Northern Lake County.

Wind Advisory from 10 PM Saturday to 10 AM PST Sunday for
Carquinez Strait and Delta-Central Sacramento Valley-Motherlode-
Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-
Northern San Joaquin Valley-Southern Sacramento Valley.

Winter Weather Advisory until 10 PM PST this evening for Burney
Basin / Eastern Shasta County-Shasta Lake Area / Northern Shasta
County.

Winter Storm Warning from 7 PM Saturday to 4 PM PST Sunday for
Shasta Lake Area / Northern Shasta County.

&&

$$



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