FXUS66 KMTR 232350
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
350 PM PST Fri Jan 23 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1209 PM PST Fri Jan 23 2026

 - Gusty offshore winds across higher terrain of the North Bay and
   East Bay Friday night through Sunday morning

 - Morning fog across some Bay Area Valleys

 - Potential weak storm system in the middle of the next work week

&&

.SHORT TERM...
Issued at 1209 PM PST Fri Jan 23 2026
(This evening through Saturday)

Low clouds linger across much of the lower elevations across the 
region this afternoon as the return of a ~1500 ft marine layer 
returned overnight. In addition, tule fog from the Central Valley as 
pushed westward into the East Bay Valleys. By mid afternoon, mostly 
sunny sky conditions are forecast expect for locations near the 
coast where the marine layer persists. 

Expecting offshore winds to develop across the higher elevations of 
the North and East Bay valleys tonight and persist into Saturday. 
Localized gust may exceed 50 mph in some of the peaks across the 
region. This will dry things out considerably in these areas which 
may also mix down into the valleys on Saturday. However, winds are 
not forecast to be strong in the lower elevations. Afternoon 
humidity values are likely to fall below 20% in the higher terrain. 

Saturday, we are expecting offshore winds to persist in the higher 
terrain. This offshore flow will work to compress the marine layer 
and essentially completely mixing it out. Thus, a slight warm up in 
temperatures can be expected with low to mid 60s for much of the 
region. 

&&

.LONG TERM...
Issued at 1209 PM PST Fri Jan 23 2026
(Saturday night through next Thursday)

Offshore winds look to diminish Saturday night into Sunday morning, 
yet will still be moderate in the higher terrain. Therefore, low 
clouds cover and/or fog will have a difficult time developing early 
Sunday morning with continued offshore flow aloft. However, high 
clouds will will begin to spread in from the west by that time. 

From the previous forecaster: "The ridge looks to flatten into 
Sunday evening, with a zonal jetstream pattern taking its place, and 
offering more onshore flow. However the jetstream looks to snap back 
to a quick ridge into the next work week. This means temperatures 
will and some bounces up and down by a few degrees, and low cloud 
formation will be spotty.

Despite the quick ridge development, high clouds look to move 
through the region as a trough develops to the west. The trough 
formation is well-argeed upon between the longer term models, but 
the trajectory is a matter of debate. More models point to a cold 
front, and maybe a weak low pushing through the area, bringing good 
chances for widespread moderate rains by the mid week. However, the 
GFS and its ensemble members seem keen on this trough getting pushed 
up against the ridge ahead of it, and placing all the moisture well 
to the north. The GFS output looks a bit less firm than other models 
and the national blend, but is something to keep in mind as the 
longer term models update. For now, the official forecast places 
rain chances in the middle of the next work week along the initial 
front with additional chances possible beyond the forecast
period."

&&

.AVIATION...
(00Z TAFS)
Issued at 350 PM PST Fri Jan 23 2026

Stratus is much more progressive on satellite than was initially 
expected so have opted for much more pessimistic 00Z TAFs. Pulled 
out clearing for STS and APC - APC may briefly clear this evening 
but this will be temporary before stratus rebuilds in. Opted to push 
the arrival of fog earlier with dense fog possible at STS and LVK. 
Ceilings should rapidly clear out by 14-18Z as moderate offshore 
winds develop across the region. Breezier afternoon conditions are 
expected tomorrow with most sites expected to be between 10-15 knots.

Vicinity of SFO...VFR. Confidence is low that stratus will impact 
SFO tonight with LAMP guidance showing a "chance" (less than 40%) of 
stratus developing from 07-11Z. HREF guidance does not clearly show 
stratus impacting SFO either so have opted to maintain SCT in the 
TAF but not adjust to overcast conditions quite yet. IF any stratus 
is able to develop it is likely to clear by 15Z due to the more 
moderate offshore flow set to develop.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR. Moderate to high confidence that MVFR 
CIGs will persist through at least 15Z. Kept the clearing time for 
MRY closer to 17Z but it could clear as early as 14/15Z. Winds shift 
southeasterly overnight before switching onshore again during the 
daytime/evening hours.

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 350 PM PST Fri Jan 23 2026

Fresh to strong northerly breezes will prevail today with near
gale force gusts in the northwest waters. Elsewhere, gentle to
fresh northerly winds prevail. Seas will build to 8-12 feet
across exposed waters today through early Saturday. Conditions
will improve this weekend with a gentle breeze and moderate seas.

&&

.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...RGass
LONG TERM....RGass
AVIATION...Kennedy
MARINE...KR

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Prepared by Boulder-Creek.com Weather at: Fri Jan 23 20:30:03 PST 2026