FXUS66 KMTR 120537
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
937 PM PST Thu Dec 11 2025
...New UPDATE, AVIATION, MARINE...
.KEY MESSAGES...
Updated at 209 PM PST Thu Dec 11 2025
- Hazardous beach conditions through Friday
- Tule fog and stratus continue for the North Bay, East Bay and
South Bay
- Light rain remains possible next week
&&
.UPDATE...
Issued at 912 PM PST Thu Dec 11 2025
Par for the course for this weather pattern, satellite shows fog
expanding back into the East Bay and North Bay. Visibility data
from Byron and the Concord Airport shows visibilities are lowering
to around 2 to 4 SM as of this evening. Given the persistent high
pressure and no real change to our atmospheric conditions, fog is
likely to be in the same locations tonight as it was last night.
While widespread dense fog is not expected, localized dense fog is
possible particularly across the North Bay Valleys and along the
delta. Make sure to take care while driving tonight and during the
morning commute and be prepared to slow down if you encounter any
sudden changes in visibility.
&&
.SHORT TERM...
Issued at 209 PM PST Thu Dec 11 2025
(This evening through Friday)
Clearing skies have finally returned to much of the region, aside
from the far interior East Bay and bay side areas of Marin County.
Thus, as high pressure remains in place over the Bay Area and
Central Coast, we are expecting to see temperatures reach into
the mid to lower 70s in the higher terrain and interior areas of
the Central Coast. Elsewhere, mid 50s to lower 60s can be expected
around much of the Bay Area, North Bay and East Bay this
afternoon. These areas still remain under the influence cooler
conditions observed in the Central Valley as offshore winds
persist.
Tonight, expecting another return of tule stratus and/or fog across
much the valleys in the North Bay, East Bay, South Bay, and areas
around the Bay Area. This is as high pressure remains parked over
the region and light to moderate offshore winds.
For Friday, temperatures will largely be above average for this time
of year, again expect for those that remain beneath the cloud cover
for much of the day. We have warmer temperatures across the board
for Friday but have largely used persistence as guidance.
&&
.LONG TERM...
Issued at 209 PM PST Thu Dec 11 2025
(Friday night through next Wednesday)
By Saturday the ridge axis shifts to the east and gives way to more
of a zonal flow aloft. However, temperatures will still remain some
5-10 degrees (up to 15 degrees in the higher elevations) above
seasonal averages. By Sunday and Monday we should begin to see high
level clouds move into the region from the north. This will be signs
of the ridge fattening and zonal flow returning with light the
potential for light rain by Monday, especially across the North Bay
and as far south as the Bay Area. Chances linger at times through
much Friday. Again, rainfall amounts are currently forecast to be
light and not amount to much more than 0.25" through next Friday
(again for the Bay Area and points northward). Little to no rainfall
(outside of the Santa Cruz Mountains) is expected across the Central
Coast and Santa Clara Valley.
From the previous forecaster: "The most interesting development in
the forecast is in the extended long range, where there is a
moderate chance for an atmospheric river late next week. It's too
early to talk about specific impacts or timing, but the Climate
Predication Center has placed the Bay Area in a moderate risk for
both heavy precipitation and strong winds from 12/18-12/21. The
bullseye looks like far northern California, but that has been
trending south over the last few model updates."
&&
.AVIATION...
(06Z TAFS)
Issued at 912 PM PST Thu Dec 11 2025
In the North Bay, KSTS is expected to remain IFR/LIFR with both vis
and cigs dropping to near minimums, through the overnight and
morning, with clearing expected in the early Friday afternoon.
KAPC will also hover between IFR/LIFR with low stratus being the
primary culprit. Given the persistent pattern, timing should also
be similar as past couple of days, with clearing beginning in the
early afternoon.
Vicinity of SFO...Light offshore flow will persist through the
forecast period with VFR conditions expected to prevail.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Similar to the Bay Area terminals, light
offshore flow is expected to produce VFR conditions through the
TAF period.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 912 PM PST Thu Dec 11 2025
Northerly winds over the coastal waters will continue tonight
into early Friday then becoming light and variable with a
gradually diminishing northwest swell through the day Friday.
Light offshore flow will persist from the Delta to the San
Francisco Bay and through the Golden Gate on Friday. Swells
continue to gradually diminish through the weekend.
&&
.BEACHES...
Issued at 1110 PM PST Wed Dec 10 2025
Long period NW swell is causing hazardous beach conditions
through Friday. This energy brings strong rip currents, an
increased risk for sneaker waves, and large breaking waves. This
coincides with nice warm weather, which will likely lure more
people to the beach under a false sense of security. A Beach
Hazard Statement is in effect through Friday evening. Respect the
power of the ocean and never turn your back on it.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Friday evening for CAZ006-505-
509-529-530.
PZ...None.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...JM
MARINE...JM
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Prepared by Boulder-Creek.com Weather at: Thu Dec 11 22:30:02 PST 2025
From the National Weather Service
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