521
FXUS66 KMTR 030908
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
108 AM PST Mon Nov 3 2025

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

.KEY MESSAGES...
Updated at 1224 AM PST Mon Nov 3 2025

 - Preparations for upcoming storm should be prioritized for today
   in Northern Sonoma and Napa. Areas south of Santa Rosa still
   have time Tuesday.

 - Mostly beneficial rainfall beginning early Wednesday morning.
   Slight potential for localized nuisance flooding in the North
   Bay.

 - Wind Advisory in effect late Tuesday night through Wednesday
   afternoon for North Bay, East Bay, SF Peninsula, and Santa Cruz
   Mtns. Gusty wind 35-45 mph with potential for brief 55 mph
   gusts along frontal passage Wednesday morning.

&&

.SHORT TERM...
Issued at 1224 AM PST Mon Nov 3 2025
(Today and tonight)

Another morning of mostly clear conditions with isolated patches
of fog along the coast. Temperatures return to normal today as
onshore flow is reinforced and we start to feel the effects of the
approaching weather system. We will see the marine layer deepen
through the next couple of days as additional moisture is advected
into the region.

&&

.LONG TERM...
Issued at 1224 AM PST Mon Nov 3 2025
(Tuesday through Sunday)

Tuesday will be our transition day into impactful weather. A
potent early season system will be digging its way into our
region. Light showers may begin as early as late Tuesday morning
across the northern reaches of Napa and Sonoma counties. These
showers will mostly be the result of orographic lift over the
terrain and will not contain the heaviest of the rain that we`re
expecting. How much rain we see out of these early showers will be
important for the rest of the event since they may increase the
likelihood of local flooding once the heavier rainfall arrive
Wednesday morning. Most of these early, prefrontal showers should
remain well to our north, but where this axis of enhanced moisture
transport sets up is still a bit uncertain. By late Tuesday, the
cold front dives southward, bringing moderate to heavy rainfall
and wind with it. Winds increase through the night Tuesday with
the heaviest rain and strongest wind expected to push through the
North Bay in the early morning hours just before sunrise, and the
rest of the Bay Area by sunrise.

Rainfall totals look to be mostly beneficial with a slight chance
for localized nuisance flooding in the North Bay, especially
dependent on how much warm sector rain we see on Tuesday. A spread
of 1-2" for the North Bay, isolated up to 2.5" in the northern
Sonoma coastal range. The rest of the Bay Area will likely end up
more in the 0.50-1.0" range, and 0.25-0.50" for the Santa Clara
Valley and Central Coast.

Regarding wind...we have issued a Wind Advisory for the North Bay,
East Bay, SF Peninsula, and Santa Cruz Mtns in effect from 10 PM
Tuesday to 4 PM Wednesday. Once again not much change in the
forecast, so we`re just consolidating our confidence intervals at
this point. Overall looking at gusts to 35-45 mph across these
areas with isolated gusts to 55 mph as the cold front passes
through Wednesday morning. This serves as a good reminder and now
is a good time to clean up any loose tree branches and other
debris that may be tossed around by the wind. Be mindful for the
morning commute and home/personal safety if you live in or travel
through treed areas. It`s never to early in the season to be
vigilant.

&&

.AVIATION...
(06Z TAFS)
Issued at 917 PM PST Sun Nov 2 2025

Generally VFR conditions across the region with some lingering
stratus along the immediate Big Sur coast. Winds are decreasing and
will remain generally light overnight. Moderate confidence in the
ceiling forecasts tonight. Dry air will intrude into the lower
layers from a baroclinic low off the coast near the Oregon-
California border, but most stratus development tonight should be
radiative in nature. Prime period for stratus development will be
early Monday morning with the stratus dissipating after sunrise.
Gentle onshore flow should return to the region Monday afternoon,
with coastal stratus returning in the evening hours. Some risk of
generally MVFR-IFR stratus in the North Bay towards the end of the
24-hour TAF period, but confidence is low at this time.

Vicinity of SFO... Moderate confidence of VFR conditions through the
TAF period. Select high resolution models are showing a chance (10-
20% probability) for radiative fog or stratus at the terminal early
Monday morning, with higher chances for stratus through the Golden
Gate with development across the East Bay terminals. Some models
indicate that stratus flow across the Golden Gate is possible, which
would complicate the forecast at the terminal. Any stratus that does
develop mixes out late Monday morning. Light to gentle northwest
breezes continue through the evening hours, turning light overnight
before resuming Monday afternoon and evening.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... VFR at present with LIFR-IFR stratus
expected to develop after midnight with moderate confidence on
timing; light drainage winds through the night. Stratus mixes out
late Monday morning as breezy onshore winds resume.

&&

.MARINE...
(Tonight through next Saturday)
Issued at 917 PM PST Sun Nov 2 2025

Fresh to strong north breezes continue to diminish overnight,
becoming moderate northwest breezes on Monday. Widespread
hazardous conditions will develop Tuesday night and continue
through Wednesday with near-gale force southerly winds with gale
force gusts, rough to very rough seas, rainfall, and a chance for
thunderstorms.

&&

.BEACHES...
Issued at 347 AM PST Sun Nov 2 2025

A long period northwesterly swell will bring an increased risk for
sneaker waves, rip currents, and breaking waves of up to 20 feet
to Pacific Coast beaches through tomorrow. High surf conditions
are possible, especially at the west and northwest facing beaches.
Remember, 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. Swimmers should always
swim near a lifeguard. Stay off the rocks, remain out of the
water to avoid hazardous swimming conditions, and never turn your
back on the ocean!

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through late tonight for CAZ006-505-509-
     529-530.

     Coastal Flood Advisory from 8 AM to 3 PM PST Tuesday for CAZ006-
     506-508-529-530.

PZ...Small Craft Advisory from 9 AM to 3 PM PST Tuesday for Pt Arena
     to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 PM PST this afternoon for Pt Arena
     to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PST early this morning for
     Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...DialH
MARINE...DialH

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