Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 132242
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
342 PM PDT Fri Oct 13 2017


.SYNOPSIS...
Dry weather continues into early next week. Gusty north winds
will return tonight into Saturday with critical fire weather
conditions expected again. Chance of rain arrives late next week.

&&

.DISCUSSION...

We want to emphasize that the gusty winds late tonight into
Saturday have heightened our concerns for fire weather conditions.
The fuels in CA are very dry right now so any fire that starts
anywhere could spread quickly and the already active wildfires add
complexity to the situation. Residents should consider having
things they need ready to go in their car in case of evacuation:
people, pets, prescriptions, papers/documents, plastic (credit &
debit cards), photos, personal computers/hard drives.

Surface pressure rises behind the upper level trough moving
across the Great Basin tonight and Saturday will result in an
increase in north to east winds over interior Norcal. Northerly
gradients forecast to increase to 11 to 14 mbs overnite and
easterly gradients forecast to about 8 mbs Sat morning. Building
surface high pressure over Nevada will result in the development
of a strong Northerly Barrier Jet on the West side of the
Sacramento Valley into Solano County after 06z or so tonight.
Forecast still on track for today into this weekend. Winds should
start to decrease Saturday night, but some areas, especially in
higher terrain, could have lingering winds into Sunday morning.
Lighter winds with slight warming in temperatures expected early
next week.

JBB/JHM

&&

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)

The extended period begins with weakening upper level high
pressure on Tuesday. An upper level low pressure system begins to
move through the Pacific northwest and break down the ridge axis
on Tuesday, allowing daytime temperatures to cool back to near
normal Tuesday into Wednesday. Models in continued agreement that
this trough will create an unsettled weather pattern midweek into
the weekend, bringing decent chances for much needed precipitation
to NorCal. Precipitation chances forecast to begin overnight
Wednesday for areas mainly north of the Sacramento area. As the
trough deepens Thursday into Friday, increased chances of
precipitation sweep over the entire interior NorCal area. Daytime
temperatures expected to cool to around 5 degrees below normal in
the southern Sacramento valley down to 15 degrees below normal in
the northern Sacramento valley and mountains. Snow levels expected
to drop to about 6000 ft to 7000 ft by Thursday night. Light snow
accumulations expected at higher elevations. HEC

&&

.AVIATION...

VFR conditions for the next 24 hours with northerly afternoon
gusty winds today. Stronger north to northeast wind increases
tonight with gusts in the 30 to 35 kt range for Coastal Range and
Sierra ridgetops, and similar wind speeds across northern and
western Central Valley by Saturday morning. JClapp

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 PM this evening to 8 AM PDT Sunday for
Carquinez Strait and Delta-Central Sacramento Valley in Glenn,
Colusa, Yuba, Northern Sutter, and Butte County Below 1000 Ft-
Eastern Mendocino NF-Eastern Portion of Shasta/Trinity NF-Lake
County Portion of Lake-Napa-Sonoma Unit-Northern Motherlode From
1000 to 3000 Ft. Includes portions of Nevada-Yuba-Placer-Amador
and ElDorado Units-Northern Sacramento Valley to Southern Tehama
County Line Below 1000 Ft-Northern Sierra Foothills from 1000 to
3000 Ft. Includes portions of Shasta-Trinity and Butte Units-
Northern Sierra Including Lassen NP and Plumas and Lassen NF/S
West of the Sierra Crest (West of Evans Peak-Grizzly Peak-
Beckworth Peak)-Northern Sierra Including the Tahoe and ElDorado
NF/S West of the Sierra Crest-Southeast Edge Shasta-Trinity NF
and Western Portions of Tehama-Glenn Unit-Southern Sacramento
Valley in Yolo-Sacramento Far Western Placer, southern Sutter
and Solano County Below 1000 Ft-Stanislaus NF West of the Sierra
Crest.

Wind Advisory from 11 PM this evening to 5 PM PDT Saturday for
Carquinez Strait and Delta-Central Sacramento Valley-Clear
Lake/Southern Lake County-Northern Sacramento Valley-Southern
Sacramento Valley.

&&

$$



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