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Area forecast discussion
National Weather Service Sacramento California
220 PM PDT sun Sep 22 2019



Synopsis...
dry and mild weather with a few showers possible over the
mountains later today. Breezy northerly winds early next week will
lead to elevated fire weather concerns. Above normal temperatures
for Tuesday and Wednesday while a significant cool down and
increasing precipitation chances return late in the week.

&&

Discussion...
a trough of low pressure will move through the northern part of
the state this evening. It's more like an inside slider type of
system so not much in the way of precipitation is expected and
mainly across the northern mountains and foothills. Amounts will
generally range from trace to a tenth of an inch. A stray shower
may be able to make its way into the north end of the valley but
for the most part expect dry conditions.

The low will move south of the area by late Monday centered
near Las Vegas. Breezy to locally windy northerly flow will
develop behind the low to elevate fire weather concerns Monday
through Wednesday morning. The strongest north winds for the
valley will occur along the west side of the valley each afternoon
and evening (monday and tuesday) where some gusts are expected
between 30 and 40 mph. The strongest northeast winds in the
mountains will occur each night into Wednesday morning with local
gusts up to 50 mph. Temperatures will be rising each day warming
well into the 90s for Tuesday within the valley and to around 80
degrees for the mountains. Some of the warmer locations over the
north end of the valley and along the west side may top out around
100 degrees.

Wednesday a light northerly flow will continue and temperatures
with temperatures remaining very warm perhaps a degree or two
warmer than tuesday's highs. This will be that last very warm day
before a cooling trend starts.

&&
Extended discussion (thursday through sunday)...

Anomalously deep troughing will settle over the western U.S. Late
this week into early next week, bringing significantly cooler
temperatures and precipitation chances across interior norcal. The
highly amplified setup over North America has been rather well
advertised as a powerful ridge across the Gulf of Alaska forces a
deep trough to position itself over the west. During the Fri-sun
timeframe, forecast highs could drop 15 to 25 degrees below
seasonal normals. Valley locations should see temperatures in the
upper 60s to low 70s, while 30s and 40s would be more commonplace
across the mountains. At this point, precipitation coverage and
amounts remain uncertain, but it appears best chances will be
over higher terrain. Snow levels could lower to around 5,500 to
6,500 foot over the weekend, so cannot rule out the potential for
some snow over the higher elevations. ~Bro/idm
&&

Aviation...

VFR conditions are expected over the next 24 hours. Northerly wind
gusts increase to 20-30 kts across the Sacramento Valley by 15z-
18z Monday.

&&

Sto watches/warnings/advisories...
red flag warning from 1 PM Monday to 11 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

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