FXUS66 KMTR 251147
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
447 AM PDT Sun Oct 25 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1207 AM PDT Sun Oct 25 2026

 - Seasonably warm conditions today

 - Cool conditions through the next week

 - Rain chances late week into the upcoming weekend

 - Minor coastal flooding at high tide for Bayshore locations
   through the week

&&

.SHORT TERM...
Issued at 1207 AM PDT Sun Oct 25 2026
(Today and tonight)

Satellite imagery reveals mostly clear skies across the region save 
for a patch of stratus that has developed near Bodega Bay and Dillon 
Beach and a little bit eastward through the Petaluma Gap. Skies 
should remain mostly clear through the next day, barring any 
radiational stratus and fog that develops within the North Bay 
early in the morning, which should dissipate after sunrise. 

A warm period continues across the region as a shortwave ridge 
sandwiched between a departing low moving into the Desert Southwest 
and an developing one off the coast of British Columbia and the 
Pacific Northwest. Highs remain seasonably warm with highs in the 
lower to middle 70s expected across the inland valleys, highs in 
the upper 70s across the warmest spots of the southern Salinas 
Valley and the Morgan Hill-Gilroy area, the upper 60s to lower 70s 
close to the Bays, and the upper 50s to middle 60s along the Pacific 
coast. A gentle onshore breeze should develop in the afternoon, with 
gusts to 20 mph possible within the Salinas Valley. 

A combination of high astronomical tides and surge from thermal 
expansion effects brings the risk of minor coastal flooding across 
Bayshore locations within the San Pablo Bay, San Francisco Bay, and 
Monterey Bay at high tide today. At the San Francisco tidal gauge, 
high tide is expected to be 1.5 ft above normal (7.3 ft MLLW) at 
11:07 AM Sunday 10/25, including around 1.0 ft of surge residual 
partially attributed to impacts from El Nino.

&&

.LONG TERM...
Issued at 1207 AM PDT Sun Oct 25 2026
(Monday through Saturday)

Large-scale troughing persists across the Western US as a low moves 
across the Pacific Northwest, and by the middle of the week, a 
second developing low over British Columbia will interact with a 
decaying low moving in from the central Pacific to reinforce the 
troughing. Some light sprinkles are possible in the northern coastal 
waters and the adjacent areas of the North Bay on Monday morning as 
the low passes by, but most of the impacts will be felt along the 
North Coast and across Oregon. Otherwise, highs will start to dip 
for the work week, with highs in the inland valleys dropping to the 
middle to upper 60s by Monday and the lower to middle 60s for the 
second half of the week.

The end of the week into the upcoming weekend is where things get 
interesting in terms of the forecast, for it is where the model 
outputs start to diverge and the resulting uncertainty ratchets 
upward. Comparing mean outputs from two of the global ensemble 
models reveals a remarkably different solution across the Western 
United States. The European ECMWF ensemble model mean suggests that 
the trough will continue handing on through the upcoming weekend 
while the American GEFS ensemble model mean depicts a slight ridge 
coming in and breaking up the trough's influence by next Sunday, the 
first day of November. Ensemble model cluster analysis for Day 7 
(Saturday) reinforces this split between a more trough-influenced 
solution from the European ensemble members, and a more ridge-
influenced solution from the American ensemble members, with the 
members of the Canadian GEPS ensemble model split between the two 
with a slight lean towards the American ensemble solution. As a side 
note, this whole discussion may illuminate why model output around 
and beyond 200 hours is generally considered unreliable by those. 
The current forecast shows rain chances coming in Friday into the 
upcoming weekend, but with the split between the models that's 
pretty much all that can be said with even a moderate degree of 
confidence. We will keep a close eye on the forecast, not least 
because it could determine whether people need to consider ponchos 
or umbrellas as part of their Halloween plans.

Coastal flooding concerns continue across Bayshore locations within 
the San Pablo, San Francisco, and Monterey Bays through the next 
week, and will expand into the Pacific coastal regions by Monday 
through Friday. At the San Francisco tidal gauge, high tide is 
expected to be 1.6 ft above normal (7.4 ft MLLW) at 11:39 AM Monday 
10/26, 1.8 ft above normal (7.6 ft MLLW) at 12:15 PM Tuesday 10/27, 
1.9 ft above normal (7.7 ft MLLW) at 12:56 PM Wednesday 10/28, 1.7 
ft above normal (7.5 ft MLLW) at 01:43 PM Thursday 10/29, 1.4 ft 
above normal (7.2 ft MLLW) at 2:39 PM on Friday 10/30, and 1.0 feet 
above normal (6.8 ft MLLW) at 3:44 PM on Saturday 10/31, including 
around 1.0 ft of surge residual partially attributed to impacts from 
El Nino.

&&

.AVIATION...
(12Z TAFS)
Issued at 447 AM PDT Sun Oct 25 2026

Widespread VFR conditions prevail through the TAF cycle. Light 
offshore winds lingered overnight which reduced the chances for fog 
development in the North Bay interior valleys. By late morning, 
onshore winds increase with high clouds dominating the skies. As the 
mid to upper-level low pressure approaches the Pacific Northwest 
Sunday evening, the marine layer will gradually reform itself. Low 
confidence on its exact impacts and how much it will deepen. If 
ceilings develop, they are likely to remain MVFR and develop after 
the current TAF package.

Vicinity of SFO...VFR. Light and variable winds become west-
northwest around 10 kt through the afternoon and gradually ease post-
sunset. A deepening marine layer Sunday night may result in a few to 
scattered low cloud decks, though not currently expecting any 
impacts to flight categories within the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR with gentle to moderate south to 
southeast breezes through sunrise. Onshore winds prevail through the 
afternoon. Low cloud decks begin to develop around sunset with 
stratus impacts likely around sunrise, though low confidence on the 
exact timing.

&&

.MARINE...
(Today through Friday)
Issued at 250 AM PDT Sun Oct 25 2026

Gentle north to northwest breezes gradually become moderate to
fresh  early next week. Strong gusts increase across the southern
coastal  waters near Point Sur and Monterey Bay by Monday
afternoon. Wind  driven moderate (4 to 8 ft) seas persist into
much of next week  while remaining slight (2 to 3 ft) at the
immediate coastline.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 3 PM PDT Thursday for CAZ006-506-
     508-529-530.

     Coastal Flood Advisory from 9 AM Monday to 3 PM PDT Thursday for 
     CAZ505-509.

PZ...Small Craft Advisory from 3 PM to 9 PM PDT Monday for Mry Bay.

     Small Craft Advisory from 3 PM Monday to 3 AM PDT Tuesday for 
     Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras 
     Blancas 0-10 nm.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Navarrete
MARINE...Navarrete

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Prepared by Boulder-Creek.com Weather at: Sun Oct 25 08:30:02 PDT 2026