Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 040630
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1030 PM PST Sun Dec 3 2017

.Synopsis...
Dry weather Monday through the week with breezy north winds
Monday and cold morning lows.

&&

.Discussion...
Update: Short wave just off the N coast at press time will be
working Swd on the backside (W side) of the interior West trof
tonight and Mon resulting in tight Nly pressure gradients and gusty
Nly winds. Current MFR-SAC gradient is about 8 mbs and forecast to
increase to about 11-12 mbs Mon morning. NAM 925 mbs increase to
over 40 kts in the Napa/Solano Co area Mon morning and it looks as
if the strongest winds in our CWA will be in Srn Lake, Wrn Colusa,
Wrn Yolo and Solano counties. These winds will be shifting west of
our CWA and offshore during the day. Surface high pressure building
in behind the trof axis will also cause strong Ely gradients and
katabatic winds over the Sierra Mon night into Tue morning as well.
First widespread freezing overnite min temps possible as well in the
Valley as winds subside Tue/Wed.   JHM

Cold front has moved east of the area and drier air is moving
into the region. Behind the front tonight into Monday the surface
gradient will increase and produce breezy to locally windy
conditions in the valley for Monday. The strongest winds are
expected over the west side of the valley and over Southern Lake
County where some gusts could be up 35 mph in the valley and up to
40 mph over Southern Lake County. Stronger northeast to east
winds will develop over the western slopes Monday night into
Tuesday where some of the favored windy locations could see gusts
around 50 mph.

Cold air advecting into the region behind the front will lead to
colder nighttime temperatures this week. The coldest mornings
look like they will be on Tuesday and Wednesday where some
locations in the valley could drop to around freezing or below.
Initially have issued the watch for the Northern San Joaquin
Valley and Southern Lake County since it looks like there might be
enough wind Monday night within the Sacramento Valley to prevent
any widespread freezing temperatures. Tuesday night into Wednesday
the winds will be lighter in the Sacramento Valley so have
expanded the Freeze Watch further northward during that time
period.

&&
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)

High pressure continues to dominate through at least the weekend
bringing dry, mild weather to interior NorCal. Above normal
daytime temperatures expected for early December as the upper
level ridge continues to amplify. Overnight temperatures will be a
few degrees below normal through Friday due to clear skies &
light winds allowing strong radiational cooling. HEC

&&

.AVIATION...

VFR conditions at all TAF sites. Could see MVFR/IFR conditions
over the Sierra through 20z due to lingering precipitation. North
winds generally less than 10 kts today. Winds increasing after 6z
Monday in Sacramento valley with gusts 20-25 kts possible north of
Sacramento. HEC

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Freeze Watch from late Monday night through Tuesday morning for
Clear Lake/Southern Lake County-Northern San Joaquin Valley-
Southern Sacramento Valley.

Freeze Watch from late Tuesday night through Wednesday morning
for Carquinez Strait and Delta-Central Sacramento Valley-Clear
Lake/Southern Lake County-Northern San Joaquin Valley-Southern
Sacramento Valley.

&&

$$



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