Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 121638
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
938 AM PDT Thu Oct 12 2017

.SYNOPSIS...
Dry with cooler temperatures for next few days. Northerly winds
breezy to gusty bringing critical fire weather conditions today
and again this weekend.

&&

.DISCUSSION...
Forecast still on track with the primary fire weather concern
being breezy to gusty winds today, then again on the weekend.

Clear skies prevail across interior Northern California, in the
wake of a dry frontal passage yesterday. Gusty north winds have
picked up behind this front, with local gusts to 35 mph being
reported over the Sacramento Valley early this morning. Visibility
has generally improved a bit this morning compared to the last
few nights, probably owing to these increased winds. Humidity
values are also extremely dry...with most locations only
rebounding to 30-50 percent this morning. A Red Flag Warning will
remain in place across much of the region through today. Winds
will diminish a bit this afternoon and tonight.

High temperatures the next few days will be a few degrees cooler
than normal owing to this cooler airmass.

The next frontal system will begin to drop southward across
Northern California late Friday into the weekend. Precipitation
will remain mainly north of our forecast area with that system,
not unlike our current windy pattern. That system is currently
modeled to take a trajectory that would be a bit windier than our
current event, though not nearly as strong as the recent winds
from Sunday, October 8. A Fire Weather Watch has been issued to
highlight concerns with the upcoming weekend event.

Dang/JBB

&&
.EXTENDED DISCUSSION (Monday THROUGH Thursday)

Weak ridging over the region on Monday will lead to above normal
temperatures for Monday by 5 to 10 degrees. A weak trough will
approach and pass through the region Tuesday and Tuesday night
but any precipitation will remain well north of the area. The main
impact will be to cool temperatures off to around seasonal
normals. Continued cooling on Wednesday as a trough deepens along
the west coast. Wednesday night into Thursday there will be a more
significant pattern change. Some model timing differences exist
but all models are indicating some much needed rainfall will move
through the northern third of the state.

&&

.AVIATION...

Northerly winds continue over the region. TAF sites will range
7-16 kts with local gusts around 20 kts today. Visibilities will
be good today for most areas with the exception of near wildfires.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until noon PDT today 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 Sacramento Valley to Southern Tehama
County Line Below 1000 Ft-Northern San Joaquin Valley in San
Joaquin and Stanislaus Counties 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)-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.

Fire Weather Watch from late Friday night through Sunday morning
for Lake County Portion of Lake-Napa-Sonoma Unit-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-Stanislaus NF
West of the Sierra Crest.

Fire Weather Watch from late Friday night through Saturday
evening for Carquinez Strait and Delta-Central Sacramento Valley
in Glenn, Colusa, Yuba, Northern Sutter, and Butte County Below
1000 Ft-Eastern Portion of Shasta/Trinity NF-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-Southern Sacramento Valley in
Yolo-Sacramento Far Western Placer, southern Sutter and Solano
County Below 1000 Ft.

&&

$$



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