Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 261800
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1100 AM PDT Tue Sep 26 2017



.SYNOPSIS...
Breezy north winds today through early Wednesday for increased
fire danger. Remaining warmer than normal through the end of the
week with lighter winds. A little cooler over the weekend.

&&

.DISCUSSION...
No significant changes to forecast so far. Overall airmass warms
a few degrees today so expect daytime highs to come in a few
degrees above Monday and about 5 degrees above normal for this
time of year. Combination of northerly flow aloft and moderately
tight surface gradient will bring another day of breezy north
winds. RDD to SAC gradient also higher than 24 hours ago so expect
the north winds to be a little higher today. Combination of
breezy north winds and low RH continue to bring increased fire
danger so Red Flag warning will remain in place through Wednesday
morning. Upper level ridge is forecast to center over the west
coast by Wednesday afternoon bringing a slight warming trend and
lighter surface gradients so should see lighter winds by the
afternoon hours. Weather pattern changes little on Thursday as the
upper ridge slides slowly eastward over the region. An upper low
pushing into the Pacific Northwest is forecast to displace the
upper ridge into the Rockies on Friday, but not expecting any
precipitation. Daytime highs Friday will be down to near normal.
&&
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)
The extended forecast is now trending cooler for the weekend as a
trough moves through Saturday, potentially followed by a deeper
trough early next week. Extended models have struggled with
consistency, so confidence has lowered. Current forecast now
projects below normal temperatures for Sunday into Monday, with
Valley highs in the low 80s, along with breezy northerly winds.
Have introduced a slight chance of rain Monday and Tuesday, mainly
for northern Shasta County. May need to expand this further if
deeper trough solution trend continues. EK


&&

.AVIATION...
VFR conditions expected for Valley TAF sites for the next 24
hours. Northerly gusts up to 20kts possible in the Sacramento
Valley today through 02z. Easterly gusts up to 30kt possible over
the Sierra crest and foothills this morning.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 AM PDT Wednesday 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 Motherlode
From 1000 to 3000 Ft. Includes portions of Calaveras-Tuolumne
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.

&&

$$



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