275
FXUS66 KMTR 121731
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
931 AM PST Wed Nov 12 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 414 AM PST Wed Nov 12 2025

 - Unsettled weather pattern returns today

 - Moderate to heavy rain and a slight chance for thunderstorms late
   tonight through Thursday

 - Strong southerly wind gusts up to 50-60 mph may cause property
   damage, downed tree limbs, and difficult travel conditions

 - Cool and unsettled weather Friday and through the weekend

&&

.UPDATE...
Issued at 903 AM PST Wed Nov 12 2025

Light rain is falling over the North Bay, with generally less than
0.05" over the past 3 hours in the higher terrain across the region
and along the coast. This is as the warm a result of orographic lift
as southwesterly winds continue to increase ahead of our main
frontal system that will move through the region late tonight and
into the morning on Thursday. The ongoing forecast remains on track
with no updates anticipated at this time. Look for a full forecast
update by 3 PM this afternoon.

RGass

&&

.SHORT TERM...
Issued at 414 AM PST Wed Nov 12 2025
(Today and tonight)

The picture from space this morning is absolutely mesmerizing. You
can clearly see the upcoming pattern change. High clouds continue to
stream in ahead of a deepening upper level low over the Pacific.
Radar shows light echos passing over portions of northern and
central CA at this time; however, soundings show a decent dry pocket
beneath the high clouds. Chances for rain will slowly increase
throughout the day, from north to south. The more prominent time for
rain will begin late tonight and into Thursday as the continues to
deepen and dig southwards as it moves towards the west coast. What
we can expect moderate to potentially heavy rain at times, and
perhaps a few rumbles of thunder. In terms of rainfall totals from
4AM this morning to 4AM Friday, the forecast amount has come up. The
North Bay will see between 1.25-5.0 inches, with the larger amounts
occuring in the higher portions of the and orographically favored
terrain. East Bay amounts vary from 0.75-2.25 inches with the higher
amounts expected over the terrain. From the San Francisco
Peninsula, Santa Cruz, and into the South Bay look for 1.25-3.5
inches. And finally for Monterey and San Benito amounts vary from
0.75-5.25". With that being said, the WPC has added a Slight Risk of
heavy rainfall around the Bay Area which may lead to poor drainage
and urban flooding due to runoff. This matches well with some of the
hi-res models and HREF where it pinpoints the potential for flooding
parts of northern California. For those commuting in the morning, be
prepared for rain and consider allowing extra time for your commute.

In addition to the rain, this system is expected to pack a potent
punch with winds. The strongest winds will be along our coastline,
especially from the North Bay Coast, including the Marin Hills, down
the San Francisco Peninsula. Here we can expected to see wind gusts
reaching 55 to 60 miles per hour, with gusts up to 70 mph possible
at favored coastal and higher terrain locations. A High Wind Warning
will go into effect from 10 PM tonight through 10 AM Thursday
morning. Elsewhere a Wind Advisory remains in effect from 10 PM
tonight through 10 AM Thursday morning 15 to 25 mph with gusts up to
45 mph.

&&

.LONG TERM...
Issued at 414 AM PST Wed Nov 12 2025
(Thursday through Tuesday)

As the front works its way through the region, we`ll be left with
post-frontal showers in its wake. An upper level trough looks to
meander over southern CA through Friday, and perhaps into the
weekend. Ensemble guidance shows either shows troughing or weak
zonal flow through early next week. This should lead to cooler
weather and unsettled weather.

&&

.AVIATION...
(18Z TAFS)
Issued at 924 AM PST Wed Nov 12 2025

Currently VFR at all terminals with the exception of SJC which has a
high-end MVFR ceiling. Low-end VFR ceilings will prevail today. Rain
showers are approaching the region from the southwest, so these can
be expected to make a run at the terminals this afternoon. Rain
showers will increase in coverage and intensity overnight with the
cold frontal passage. Southerly winds will increase ahead of the
cold front, becoming the strongest and gustiest during the
passage. An embedded thunderstorm cannot be ruled out, but
confidence is too low in timing and location to include in the
TAF. No definitive low-level wind shear, but bumpy conditions can
be expected. During the time of heaviest rainfall, MVFR conditions
can be expected to prevail with further deterioration possible.

Vicinity of SFO...Currently VFR with southerly flow. Low-end VFR
ceilings will prevail today. Southerly winds will increase through
the day, becoming gusty this afternoon. Rain showers are expected by
mid-afternoon, increasing in coverage and intensity overnight with
moderate rain expected by mid-morning. Conditions improve towards
the end of the 30 hour TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR and calm at MRY and VFR with
moderate drainage flow at SNS. Low-end VFR ceilings will prevail
today. Southerly winds will increase through the day, becoming
gusty this afternoon. Rain will approach the terminals towards the
end of the TAF period with the heaviest rainfall for the terminals
expected in the next TAF period.

&&

.MARINE...
(Today through Monday)
Issued at 903 AM PST Wed Nov 12 2025

Widespread hazardous marine conditions will develop this afternoon
with conditions deteriorating through tomorrow morning. Rain
showers this afternoon will increase in coverage and intensity
tonight into tomorrow morning with embedded thunderstorms
possible. Widespread gale force gusts are expected tonight through
tomorrow morning with storm force gusts expected for the northern
waters. Winds will quickly diminish Thursday night. Moderate seas
today will build to become rough for the inner waters and very
rough for the outer waters Thursday through Friday. Seas abate to
become moderate by Saturday.

&&

.BEACHES...
Issued at 414 AM PST Wed Nov 12 2025

Wave bulletins recently are showing potential for hazardous surf
conditions developing late to very late Thursday night and Friday.
However, currently it`s a low confidence forecast as to whether
we`ll reach beach hazard criteria or possibly high surf advisory
criteria. Complicating the forecast is in situ rapidly deepening
low pressure development 400 miles northwest of San Francisco that
has itself rapidly evolved just since the weekend, and part of
potentially hazardous surf may be related to the local wind field
in the vicinity of the storm developing in the nearest term. Wave
model forecasts also currently show much of the wave energy over
the offshore waters passing by to our west late this week which
may help mitigate coastal hazards. Please stay tuned to further
updates.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Warning from 10 PM this evening to 10 AM PST Thursday
     for CAZ006-502-505-509.

     Wind Advisory from 10 PM this evening to 10 AM PST Thursday for
     CAZ503-504-506-508-510-512>518-528>530.

PZ...Small Craft Advisory until 3 PM PST this afternoon for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60
     NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to
     Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.

     Gale Warning from 3 PM this afternoon to 9 AM PST Thursday for
     Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos
     10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-SF Bay N of
     Bay Bridge.

     Gale Warning until 9 PM PST this evening for Pt Arena to Pt
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Storm Warning from 9 PM this evening to 9 AM PST Thursday for Pt
     Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt
     Reyes to Pigeon Pt 0-10 nm.

     Gale Warning from 3 PM this afternoon to 9 PM PST this evening
     for Pt Reyes to Pigeon Pt 0-10 nm.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Sarment
MARINE...Sarment

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