Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 242139

Area Forecast Discussion
National Weather Service Sacramento CA
239 PM PDT Thu Sep 24 2020

A cold front pushed across northwestern California bringing some
precip mostly to the northern Coast Range earlier today. Going
forward, dry weather is expected to prevail with normal
temperatures through Friday. With very dry fuels, increasing
north and east winds ushering in drier air Saturday through
Monday, leading to fire weather concerns. Unseasonably hot
weather returns Sunday and continues next week.


Fair weather today with mostly clear skies and near average
temperatures across the region. Similar conditions can be seen today
as compared to yesterday afternoon. Most areas are a hair cooler
with slightly higher humidity, thanks to continued onshore flow.

This is going to change however, as ensemble guidance is in good
agreement we will transition from a zonal pattern to one of
ridging by this weekend. As high pressure begins to build back
into our area, we will see a wind shift from the persistent delta
flow we have experienced all week. This wind shift will happen on
Saturday in the form of a drying north and east winds. As the
surface pressure gradient tightens on Saturday afternoon,winds will
ramp up across the western Sacramento Valley and the Cascade and
northern Sierra Nevada mountains. The strongest gusts are expected
overnight Saturday into early Sunday morning. Wind gusts are
expected to be near 30 mph, with some potential gusts to 40 mph
through wind favored cannons. Sunday will see winds decrease a
bit, but another round of gusty winds looks to develop Sunday
night into Monday. These winds will also bring drying conditions
with humidities lowering into the teens. Due to these conditions,
the fire weather watch for Saturday through Monday morning looks
on track.

Sunday will also be the beginning of a warming trend across the
Sacramento Valley. Temperatures will warm into the lower 90s with
overnight lows staying mild in the middle to upper 60s thanks to
the increased winds.


High pressure originating from the Pacific continues to build
over the West Coast through next week, bringing dry weather and
hot temperatures to interior NorCal. Daytime temperatures will be
10 to 15 degrees above average through next week with some Valley
locations seeing multiple days of 100+ degree temperatures.
Widespread moderate heat risk is expected in the Valley and
foothills which could impact any sensitive groups including
outdoor workers. As high pressure amplifies through the week,
winds should become lighter by mid- week with clear skies
prevailing (with the exception of any smoke or haze from area
wildfires). Looking a bit further, dry weather and warmer
temperatures are likely to continue into the weekend.


Mainly VFR conditions for the next 24 hours with the exception of
local MVFR at times at RDD/RBL due to wildfire FU/HZ. Gusts up to 25
knots in the Delta vicinity and up to 20 kts in the northwestern
San Joaquin Valley in the evening hours. Elsewhere, winds
generally below 12 knots.


Fire Weather Watch from Saturday morning through Monday morning
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-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 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)-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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