285
FXUS66 KMTR 040935
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
235 AM PDT Sat Oct 4 2025

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1245 AM PDT Sat Oct 4 2025

 - Warmer and drier conditions through mid week.

 - Next chance for rain late next week.

&&

.SHORT TERM...
Issued at 1245 AM PDT Sat Oct 4 2025
(Today and tonight)

The 500 mb low has moved into Nevada and will continue NE while
being absorbed back into the long wave pattern over the next 24
hours. Meanwhile a surface low pressure trough will develop over
California. The gradient between this low pressure and building
high pressure over the subtropical Eastern Pacific will support
moderate N-NW winds along the coast and NW-SE oriented valleys.
The marine layer will gradually recover today as warmer, drier
air moves over the stable pool of cool air near the surface.
Temperatures will be near seasonal normal with mid to upper 70s
inland and mid to upper 60s along the coast. Overall a pretty nice
Saturday.

&&

.LONG TERM...
Issued at 1245 AM PDT Sat Oct 4 2025
(Sunday through Friday)

The trough over California will gradually shift towards the coast
starting Sunday, nudged by weak upper level troughing. The upper
level trough will evolve into a cut-off low off the Central Coast
by Sunday, further pushing the surface trough to the coast or even
offshore. As the surface trough shifts further west, high pressure
will build over the northern Rockies. This set up will support
down-gradient, offshore N or NE winds. These winds will bring a
warmer, drier air mass to the Bay Area from Sunday through mid
week. The 500 mb height will remain below the median for this
time of year (5800 m) which will moderate the temperatures and
should allow a 1,000-1,500 ft marine layer to survive under the
offshore winds. The skies will be clear in the afternoon, but
morning clouds are still expected in the typical marine layer
locations this week. While the minimum humidity will drop below
30% across the North Bay interior mountains, the mild
temperatures, moderate wind speed, and higher than normal fuel
moisture will limit fire weather concerns.

The offshore winds will die down by Friday as a new, deep low
pressure system approaches the west coast and becomes the dominant
feature. This system will bring a cold front through the Bay Area
next weekend, with some rain likely. The ensembles have backed
off on the amount, however. There is now a 10-30% chance of
receiving more than 1" of rain across the North Bay, with less
than 10% of reaching that threshold across the rest of the cwa.
The disturbed weather looks to last for several days, with
stratiform rain ahead of the front, and showers after it moves
through.

&&

.AVIATION...
(06Z TAFS)
Issued at 925 PM PDT Fri Oct 3 2025

VFR-MVFR except patchy valley fog /IFR-LIFR/ late tonight and
Saturday morning. Mainly west to northwest winds 5 to 12 knots
except light cool air drainage winds in the valleys late tonight
and Saturday morning.

Vicinity of SFO...VFR except tempo MVFR 12z-16z Saturday. West
wind diminishing to 10 knots tonight. West wind near 10 knots
Saturday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR-MVFR. West to northwest winds 5 to
10 knots tonight. Light southeast winds in the valleys late
tonight and Saturday morning. Winds west to northwest 10 to 15
knots Saturday afternoon and early evening.

&&

.MARINE...
(Tonight through next Thursday)
Issued at 814 PM PDT Fri Oct 3 2025

Fresh to gale force breezes are forecast, especially for the outer
waters near and north of Pigeon Point tonight into the pre-dawn
hours Saturday. This will translate to steep and rough seas up to
10 feet resulting in hazardous boating conditions. Winds abate
after through sunrise Saturday, however, fresh to near gale-force
northerly winds resume Saturday afternoon. Winds and seas ease
next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT early this morning for Mry
     Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-
     10 nm.

     Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Gale Warning until 3 AM PDT early this morning for Pt Arena to
     Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Sunday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Canepa
MARINE...Canepa

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