FXUS66 KMTR 241147
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
347 AM PST Mon Nov 24 2025
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1226 AM PST Mon Nov 24 2025
- Dry and mild this week with stratus overnight and through the
morning
- Cooler temperatures this weekend as the next system approaches
- Confidence increasing for gusty offshore winds by the end of
the upcoming weekend
&&
.SHORT TERM...
Issued at 1226 AM PST Mon Nov 24 2025
(Today and tonight)
The stratus layer envelops most of the Bay Area valleys and extends
in to the Monterey Bay and Salinas Valley regions, with the
expectation that the layer continues to build through the night
somewhat undercut by the clearing of the Santa Rosa Plain. Will
monitor how the stratus evolves through the night, but will hold
firm on seeing a general expansion of the stratus layer through the
rest of the morning. A more pressing question will be how dense fog
evolves through the next several hours. At this point the only
station that has consistently reported dense fog (1/4 mi visibility
or less) is Byron in the southeastern corner of Contra Costa County,
with trends across the Central Valley suggesting that dense fog is
also present across the eastern tier of Contra Costa County (east of
the Diablo Hills, including the Antioch area). Fog has also been
reported across other regions of the Bay Area, including Concord and
Novato, but we have not seen the widespread dense fog anywhere that
would trigger a Dense Fog Advisory. If observations show more
widespread fog development, one may need to be issued later this
morning. For those morning commuters who do encounter dense fog,
slow down, use low-beam headlights, and allow extra distance between
you and the car in front of you. In any case, stratus should begin
to dissipate sometime after sunrise and be generally cleared out by
the afternoon.
The weather pattern remains largely similar to yesterday's with a
weak ridge aloft and a gentle onshore flow this afternoon. High
temperatures range from the middle to upper 60s in the inland
valleys to the upper 50s to middle 60s across the coastal and
Bayside regions.
&&
.LONG TERM...
Issued at 1226 AM PST Mon Nov 24 2025
(Tuesday through Sunday)
A building ridge aloft brings a gradual warming trend for Tuesday
into Thanksgiving (Thursday), compressing the marine layer and
raising temperatures by a few degrees, with the rise in temperatures
somewhat balanced out by some cold air advection stemming from an
interaction between a building high in the east Pacific and a
building low in the Desert Southwest. The warmest spots of the
inland valleys (think the Morgan Hill-Gilroy region and the southern
Salinas Valley) might touch the lower 70s on Wednesday and Thursday.
Towards Friday into the upcoming weekend, a pattern change will
occur as the ridge over the western United States breaks down, and
one amplifies upstream across the Gulf of Alaska. As a result, cold
Arctic air descends into the Mountain West and Central Plains
states. Ensemble model guidance continues to point to this system
following more of an inside slider like development in our region.
In other words, the impacts of this trough fall into the windy and
dry side rather than the rainy side. Still too early to tell how
strong the impacts will be and where the greatest threats will
occur, but the current forecast has a period of gusty offshore winds
developing across the Bay Area and Central Coast late Saturday
through, and somewhat beyond, the end of the 7-day forecast period.
Confidence in the exact nature of the impacts will improve through
the rest of the week, so keep in touch with the forecast updates for
the most up to date information.
&&
.AVIATION...
(12Z TAFS)
Issued at 332 AM PST Mon Nov 24 2025
Low level stratus has filled in across the interior valleys,
along with patchy dense fog across portions of the North Bay,
including KSTS which is expected to remain LIFR/IFR until clearing
out later this morning.
Vicinity of SFO...Weak surface meso low/otter eddy over the Bay
Area combined with weak onshore flow just above the marine layer has
resulted in some drier air mixing closer to the surface and less
coverage than we saw 24hrs ago. MVFR ceilings are expected to
persist through sunrise before clearing out by late morning/early
afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Low level stratus has filled in over the
Salinas Valley and is expected to persist with IFR ceilings
through mid-morning, then VFR for the remainder of the day and
evening. A transition to weak onshore flow today will bring
MVFR/IFR ceilings back late tonight into early Tuesday morning.
&&
.MARINE...
(Today through Saturday)
Issued at 332 AM PST Mon Nov 24 2025
Seas have begun to ease and will continue to do so through the
middle of the week as high pressure build across our area. Expect
light to moderate northerly breezes through early Thursday. By the
end of the week into next weekend, winds will begin to increase
along with building seas.
&&
.BEACHES...
Issued at 614 PM PST Sun Nov 23 2025
A Beach Hazards Statement is in effect through Monday evening. A
long period northwesterly swell will result in an increased risk
for sneaker waves and rip currents. Breaking waves of 13 to 18
feet are expected. Sneaker waves can unexpectedly run
significantly farther up the beach than normal, including over
rocks and jetties. Rip currents are typically more frequent and
stronger in the vicinity of jetties, inlets, and piers.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through this evening for CAZ006-505-509-
529-530.
PZ...None.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...JM
MARINE...JM
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Prepared by Boulder-Creek.com Weather at: Mon Nov 24 08:30:02 PST 2025
From the National Weather Service
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