Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 250601
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1000 PM PST Fri Nov 24 2017

.Synopsis...
Mostly dry and mild during the day Saturday. Widespread rain
spreads south Saturday night and Sunday followed by a colder
system with mountain snow Sunday night into early Monday.

&&

.Discussion...
Some WAA light rain/sprinkles off the Bodega Bay coast are forecast
to spread NEwd across interior Norcal roughly N of a UKI-Lassen Park
line after midnight to about 12-15z. Otherwise, abundant mid to high
level cloudiness should once again preclude widespread F+ in our
CWA.

Stockton posted a new record high for the date at 76, breaking the
old record of 74 set in 1959. Modesto so far has made it to 75, 2
degrees shy of the record set in 1939.

Most of the region will remain dry and mild on Saturday. Some
morning mist and some patches of fog are possible, but cloud cover
will limit more widespread dense fog. A weak weather system brushes
the far north and precipitation chances will be limited to the far
northern portion of the state. High temperatures should be similar
to those we`ve seen today.

More widespread precipitation is expected Saturday night into
Sunday, with high snow levels. Models have slowed down the projected
speed of this system, with mainly dry conditions until after
midnight. Light to moderate rain will spread across the area south
of I80 during the day Sunday.

A colder system arrives Sunday night and continues into Monday.
This system has been trending wetter but also a little slower.
Accumulating snow is likely to impact travel. with. Snow levels
are expected to drop below the higher northern Sierra pass levels
Sunday evening as colder air pushes in, though there is some
uncertainty as to exactly when this will happen. Mountain
travelers should be prepared for winter driving conditions
overnight Sunday through Monday morning. Current projections
suggest snowfall of 4 to 8 inches above 6000 feet, up to a foot
over higher mountain peaks. In addition to snow, winds gusting up
to 55 mph in the Sierra are possible. In the northern Sacramento
Valley, there could be gusts to 40 mph.

There is uncertainty as to how quickly the system exits on Monday.
The GFS moves it out by mid day, while the ECMWF keeps it going
through the afternoon. This could greatly impact the amount of
snowfall in the Sierra. EK

&&
.EXTENDED DISCUSSION (Tuesday THROUGH Friday)



Seasonal weather for interior NorCal begins Tuesday as high
pressure dominates through the extended period. The building ridge
could produce gusty winds across the valley and mountain ridgetops
Wednesday through Thursday. Nightly fog is possible Tuesday and
Wednesday, though the development of strong winds could limit fog
formation. Models are hinting at another storm system impacting
the West Coast next weekend. However, consensus is very low on
timing and location of impact. HEC
&&

.AVIATION...


VFR conditions through the evening. Patchy fog could create
MVFR/IFR conditions after 6z Saturday. Light winds for all TAF
stations.

&&

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$



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