000
FXUS66 KSTO 041118
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
318 AM PST Mon Dec 4 2023


.Synopsis...
Areas of dense fog in the Valley today and likely tomorrow
morning, mainly from Marysville southward. Warm and dry to start
the week, then shower and high elevations snow chances return
Wednesday through Thursday.

&&

.Discussion...
Areas of patchy fog are being observed on traffic cameras across
the Sacramento Metro Area this morning along with few passing
high clouds this morning with areas of mountain fog per GOES-West
satellite imagery. An upper level ridge axis passing over
California resulting in very light to no winds is already
promoting areas of dense fog in the Sacramento Valley this
morning. Coverage likely to increasew in these early morning hours
across portions of the central Sacramento Valley. The HREF is
showing a 50-80% chance of visibility less than 1/4 mile in the
Sacramento Valley and Delta beginning from Yuba City down to
Stockton. Similar foggy conditions will likely occur tomorrow
morning from Yuba City southward past Modesto and potentially in
the Redding/Anderson area of the northern Sac Valley. Remember to
slow down and use low beam headlights if fog is encountered while
driving. Conditions on both days should clear by 11AM as the fog
mixes out.

Dry weather will continue through Tuesday as the aforementioned
high pressure ridge remains over California. Precipitation chances
return to the region beginning Wednesday as a low pressure trough
located off the coast of the Pacific Northwest moves onshore. The
bulk of the precipitation is expected to fall over the northern
Sacramento Valley and surrounding mountains early Wednesday before
coverage becomes more widespread later in the day. Currently, the
NBM is projecting a 60-80% chance of an 1" or more of rain over
the Northern Sacramento Valley and surrounding mountains. For rest
of the Valley, precipitation totals are expected to be lower with
only a 20-60% chance of areas receiving 0.50" of rainfall.
Rainfall amounts are expected to be lower Thursday morning through
the afternoon with only a 30-50% chance of the northern Sacramento
Valley and surrounding mountains seeing an inch or more of
rainfall. Snow levels will be around 7000-8000 feet on Wednesday
before lowering to 6000-7000 feet Thursday morning. Snow amounts
are trending lower but a few inches are still possible.

&&


.EXTENDED DISCUSSION (Friday THROUGH Monday)...
Friday will be a transition day with high pressure starting to
build over the region and potential breezy northerly winds for the
valley. A few lingering showers will be possible and those should
mainly be over the mountains. Both Clusters and deterministic
models are in good agreement with building a ridge over the area
starting on Friday and lasting into Sunday. Uncertainty increases
next week with the deterministic models indicating a breakdown in
the ridge starting late Sunday into Monday while the clusters are
keeping a ridge over the area. The NBM is still keeping some
showers over the area this weekend but the trend is towards more
dry weather.

&&

.AVIATION...
Areas of MVFR/IFR/LIFR in BR/FG from 12Z-19Z Monday (50-80%
probability of 1/4 SM visibility, mainly from MYV southward).
Surface winds will remain below 10 kts. Similar foggy conditions
expected tomorrow morning.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 10 AM PST this morning for Carquinez
Strait and Delta-Central Sacramento Valley-Northern San Joaquin
Valley-Southern Sacramento Valley.

&&

$$