FXUS66 KMTR 251137
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
337 AM PST Tue Nov 25 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 144 PM PST Mon Nov 24 2025

 - Dry and mild conditions continue until the end of the week 

 - Cooler temperatures this weekend as the next system approaches

 - Gusty offshore winds are possible by the end of the upcoming 
   weekend

&&

.SHORT TERM...
Issued at 252 AM PST Tue Nov 25 2025
(Today and tonight)

Primary concern in the short term is the dense fog that has 
developed overnight across the North Bay Interior Valleys and East 
Bay Interior Valleys, and may eventually have to be expanded further 
as we head toward and through sunrise. Attm a Dense Fog Advisory is 
in effect for the North Bay Interior Valleys and East Bay Interior 
Valleys until 11AM this morning. 

An offshore surface high pressure under broader ridging aloft is 
pulling a weak fetch of offshore flow across much of our area today 
and tomorrow. Subsidence beneath the ridge should keep a shallow 
marine layer just offshore this afternoon and evening area wide, 
resulting in a nice day. Todays temperatures will be similar to 
yesterday for the North Bay and Bay Area, slightly warmer for inland 
areas over the Central Coast where morning fog won't be as 
extensive. Patchy dense fog is expected to develop once again later 
tonight into the overnight hours over the North Bay Interior 
Valleys, however coverage should decrease as drier air associated 
with the shifting ridge mixes closer to the surface.

&&

.LONG TERM...
Issued at 252 AM PST Tue Nov 25 2025
(Wednesday through Monday)

Gradual warming through the middle of the week remains on track with 
temperatures peaking on Thursday afternoon while a progressive 
trough to our north continues to quickly get deflected north and 
east of our area. Weak amplified ridging aloft over the Pacific 
Northwest on Friday won't stop a weak back door cold front from 
pushing south through our area during the day Friday, cooling most 
areas off by a few degrees. The forecast for the weekend and 
beyond lacks consensus, but cooler temperatures than what we'll 
see the next few days seems likely as the longwave synoptic 
pattern becomes highly amplified, allowing for cooler Canadian air
to filter south across the entire West Coast.

&&

.AVIATION...
(12Z TAFS)
Issued at 337 AM PST Tue Nov 25 2025

LIFR-VLIFR conditions have developed across the North Bay valleys, 
parts of the East Bay exposed to the influence of the Central Valley 
fog bank, and the southern reaches of the Salinas Valley. The 
Central Valley fog has taken advantage of drainage flows and has 
dropped into parts of the San Francisco Bay, where SFO is currently 
reporting an IFR ceiling although with good surface visibilities. 
Some further expansion of the stratus is possible, particularly as 
clear skies across the rest of the region promote radiational 
cooling effects. Light offshore flow will continue across the region 
through the day, promoting a continued feed from the Central Valley 
fog minus any solar heating and potentially delaying clearance times 
across the Bay Area. This, in turn, could continue to promote dense 
fog formation tonight into Wednesday, although the exact details are 
not certain at this time.

Vicinity of SFO... IFR conditions at best through the morning hours, 
with the southwest flow helping stave off the most severe impacts 
from the Central Valley fog bank. A more northerly flow developing 
through the morning could bring poor visibilities to the terminal. 
Stratus will take quite a while to clear out this morning with light 
winds expected through the day. There is the potential for stratus 
and low fog to develop tonight through Wednesday morning, which is 
not being captured very well by the high resolution models. Have 
kept the TAF above IFR for now, but pilots should keep track of TAF 
updates as the day evolves in case the chances for fog increase.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... Low to moderate confidence of VFR 
conditions through the TAF period. Clear skies and dry offshore 
flows can promote radiational cooling, but the winds also mix the 
lower layers and prevent stratus from forming through the morning. 
VFR conditions continues through the late afternoon with winds 
shifting to a light onshore flow.

&&

.MARINE...
(Today through Sunday)
Issued at 252 AM PST Tue Nov 25 2025

Dense fog has developed across the West Delta, into the San Pablo
and San Francisco Bays, creating hazardous conditions for
mariners through the morning hours. High pressure will persist
over the coastal waters through mid to late week. Seas will
gradually ease through the middle of the week with gentle to
moderate northerly breezes. Winds will begin to increase again
late week, building moderate to rough seas.

&&

.BEACHES...
Issued at 923 PM PST Mon Nov 24 2025

The Beach Hazards Statement has been extended through 10 AM PST 
Tuesday. 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 until 10 AM PST this morning for CAZ006-
     505-509-529-530.

     Dense Fog Advisory until 11 AM PST this morning for CAZ506-510.

PZ...Dense Fog Advisory until 11 AM PST this morning for SF Bay N of 
     Bay Bridge.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...DialH
MARINE...DialH

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Prepared by Boulder-Creek.com Weather at: Tue Nov 25 06:30:02 PST 2025