Area Forecast Discussion
Issued by NWS Sacramento, CA

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776
FXUS66 KSTO 210557
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
947 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...
Bright band over the Motherlode suggesting a mix of wet snow and
graupel around the 3500 ft level. This band will be moving into
higher Sierra elevations by midnight, continuing the heavy snow for
zone 69.

Cold and unstable atmosphere swinging through NorCal will continue
the showery regime tonight and into Saturday. This will provide
somewhat of a break over the Wrn portions of the CWA until the next
storm system.

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. NAM 925
mbs winds look as strong or even stronger than last Wed evening and
we will consider high wind warning for portions of the valley.

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.   /JHM

&&

.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.

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

&&

$$



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