FXUS66 KMTR 230001
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
401 PM PST Thu Jan 22 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 213 PM PST Thu Jan 22 2026

 - Morning fog across some Bay Area Valleys and around Monterey

 - Gusty offshore winds across higher terrain of the North Bay
   late Friday into Saturday

 - Potential weak to moderate storm system next week around
   Wednesday

&&

.SHORT TERM...
Issued at 213 PM PST Thu Jan 22 2026
(This evening through Friday)

The closed low that brought showers to the area last night and
this morning is spinning further away to the south. An inside
tracking low pressure system (inside slider) will quickly dig into
Nevada late Friday. As a result, temperatures will not recover and
remain around normal, some issues will continue, and north to
northeast winds will start to develop. 

For the low clouds and fog, coverage should be fairly similar to
this morning, with the north hills, southern Bay Area, and
Monterey areas likely to see some. Visibilities could drop to
below 1 mile in some spots.

For the winds, speeds will be fairly light through mid-day Friday,
then northerly winds will start to pick up. By Friday evening,
gusts of 25 to 35 mph will develop mainly over the interior 
mountains of the North Bay area. The winds will turn northeasterly
and spread by early Saturday (see long term section).

&&

.LONG TERM...
Issued at 213 PM PST Thu Jan 22 2026
(Friday night through next Wednesday)

As the cold air from the insider slider settles into Idaho and
Nevada on Saturday, the offshore leaning surface pressure 
gradients will strengthen. The winds aloft will also become 
offshore from the surface through and above 10,000 feet, resulting
in a deep layer of 25 to 35 knot flow. The combination of this 
surface pattern and moderate upper level support will allow the 
winds at the ground to shift to north to northeasterly and expand 
on Saturday, then persist into Sunday. The winds will affect much 
of the wind prone areas, but be focused over the northern 
mountains and hills where wind gusts of 25 to 35 mph will be 
common, and isolated gusts of 45 mph are possible. The air will 
also get very dry, but fire weather concerns are low due to the
state of the fuels.

The offshore flow will shut down by Monday as weak ridging aloft 
will bring fairly quiet conditions into Tuesday. Some low clouds 
and fog will likely form over the coastal areas as the marine 
layer reestablishes itself. 

Then big question marks start to pop up after that. About half of
the ensemble projections show a rain making cold front moving 
down the coast around Wednesday or Thursday, with some gusty south
winds. The other half do not. If it does rain, the amounts will 
be light as none of the individual runs have anything over an 
inch.

&&

.AVIATION...
(00Z TAFS)
Issued at 332 PM PST Thu Jan 22 2026

The big story for the aviation forecast is the potential for fog 
formation overnight. Current dew points are in the mid to upper
40s across the San Francisco Bay Area, and low 50s across the
Monterey Bay area. This is a few degrees higher than yesterday,
but the temperature are anywhere from 5-15 degrees warmer so the
RH is actually lower across the board. However, the clearing skies
will allow for enhanced radiational cooling in the valleys. The
effect will be bolstered by the return of onshore winds and the
reintroduction of a cool, moist marine influenced air mass near
the coast and adjacent valleys.

Vicinity of SFO...The marine layer is expected to be around 1,000
feet deep when the onshore flow returns throughout the boundary
layer this evening. That's deep enough to spill over San Bruno
Mountain and impact the terminal. It's unclear if this will be in
the form of ceilings, fog, both, or neither. The most likely
outcome is IFR ceilings through the morning hours, but there is
still a lot of uncertainty until the winds flip to onshore and
clouds start to fill the coastal waters.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Marine layer impacts are expected at both
MRY and SNS Thursday night through Friday morning, with higher 
confidence than the northern terminals due to the higher dew 
points. 

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 113 PM PST Thu Jan 22 2026

North winds and choppy seas will steadily increase through Friday
over the region, strongest over the northern outer waters. Small
Craft Advisories are already posted, with a 30 percent chance of
localized Gale Force winds over the outer waters off Point Arena
on Friday. Seas and winds will gradually ease Saturday afternoon
and remain around typical into the beginning of next week. Steep
seas and gusty south winds possible around mid-week with a storm
system.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PST Saturday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...RK
LONG TERM....RK
AVIATION...Flynn
MARINE...RK

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Prepared by Boulder-Creek.com Weather at: Thu Jan 22 16:30:03 PST 2026