329
FXUS66 KMTR 122336
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
436 PM PDT Sun Oct 12 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 215 PM PDT Sun Oct 12 2025

 - Widespread rainfall and isolated thunderstorms Monday and Tuesday

 - Heaviest rainfall is likely across the Central Coast

 - Warming and drying trend kicks off Wednesday

&&

.SHORT TERM...
Issued at 215 PM PDT Sun Oct 12 2025
(This evening through Monday)

Yet another beautiful afternoon across the region with sunny skies
and temperatures warming into the low to mid 60`s near the coast and
lower 70`s across the interior. Breezy conditions are occuring near
the coast and in the higher elevations with gusts between 20 and 30
mph, however stronger northwesterly winds are occuring just
offshore. Tonight temperatures will cool into the upper 40s to mid
50s across much of the region. However, increasing cloud cover from
an approaching cold front is likely which may limit radiational
cooling.

Rain showers return to the region on Monday, first over the North
Bay around or after sunrise and then over the greater San Francisco
Bay Area by midday. Isolated thunderstorms are also expected as the
front progresses southward into the Central Coast by early
afternoon. This is as CAPE values approach 500 J/kg and lapse rates
reach or exceed 7 C/km as the airmass aloft becomes more unstable
late Monday morning through the evening. The front is currently
expected to clear the Central Coast around 7 PM PDT with post-
frontal rain showers and isolated thunderstorms continuing into
Monday night and Tuesday morning.

&&

.LONG TERM...
Issued at 215 PM PDT Sun Oct 12 2025
(Monday night through next Saturday)

On Tuesday, lingering post-frontal rain showers and isolated
thunderstorms will persist, especially over the Central Coast before
the mid/upper level low pushes inland. Winds will be strongest over
the Central Coast and into the Diablo Range Monday afternoon and
into Tuesday morning with southwesterly gusts up to 50 mph,
especially in the higher elevations. This does not appear to be long-
lived  or encompass enough of an area to warrant a Wind Advisory,
however we will continue to monitor closely.

Rain chances will greatly diminish Tuesday night and moreso into
Wednesday as the pushes into Nevada. In fact, most of the day on
Wednesday will be dry across the region. Rainfall totals from Monday
through Tuesday night: 0.25"-0.75" across the North Bay; 0.50"-1.00"
across the Bay Area, East Bay, South Bay, and southern Salinas
Valley; 1.00"-1.25" around the Monterey Bay; 1.25"-1.75" in the
Santa Cruz Mountains, Santa Lucia Range, and Diablo Range. Isolated
higher amounts up to 3.00" will be possible especially in the higher
peaks of the Santa Cruz Mountains and Santa Lucia Range. Any heavier
showers and/or thunderstorms will be capable of producing lightning,
brief heavy downpours, and gusty, erratic winds. This amount of
rainfall would lead to minor/nuisance flooding concerns across much
of the Central Coast.

Tuesday night will be a cold one, with the coldest temperatures
expected across interior Central Coast with lows dropping into the
upper 30`s to lower 40`s. From the previous forecaster: "With the
recent rainfall, conditions will feel colder than what the
thermometer reads - please take care of people, pets, and plants.

Global ensemble clusters are in agreement that the upper-level low
will weaken and shift east Wednesday into Thursday with the help of
upper-level shortwave ridging nosing in from the Eastern Pacific
Ocean. This feature will quickly get flattened by an upper-level
shortwave trough, putting the region under the influence of the
eastern periphery of the high pressure over the Eastern Pacific
Ocean. This will translate to a warming and drying trend Wednesday
through Saturday."

&&

.AVIATION...
(00Z TAFS)
Issued at 423 PM PDT Sun Oct 12 2025

Clear skies will continue this afternoon but an approaching storm
will bring drastically different conditions tomorrow. High clouds
will gradually lower through the night as the system approaches.
By midday Monday a band of strong showers and possible
thunderstorms will push through as an occluded front and the
associated surface low moves through. This system will also bring
shifting winds in addition to the erratic gusts associated with
any strong showers or thunderstorms. Showers should become lighter
and more scattered after 14/06Z or so, but the chance for
isolated thunderstorms will continue through Tuesday afternoon.

Vicinity of SFO...Mostly clear skies and moderate westerly winds
will continue through the afternoon. High clouds will roll in
overnight and winds will remain stronger than normal through
Monday morning. The first band of organized showers is expected
to arrive around 18-20Z. The stronger cells should last until
around 01Z before the intensity starts to wane. There is a 20%
chance for embedded thunderstorms within the first push of strong
showers. Temporary erratic gusty winds and sharp visibility drops
are possible through Monday afternoon.

SFO Bridge Approach...Ceilings are expected to be between 3,000
and 5,000 feet when the showers arrive Monday, impacting the
approach.

Monterey Bay Terminals...All indications are that the storms will
be more organized along the Central Coast Monday afternoon. These
terminals have the best chance for thunderstorms (roughly 30%,
peaking in the evening) and TSRA has been added to the TAFS for
MRY and SNS.

&&

.MARINE...
(Tonight through next Friday)
Issued at 423 PM PDT Sun Oct 12 2025

Strong NW wind are being reported across the coastal waters, with
rough seas up to 12 feet. A deep low pressure system will move
over the coastal waters Monday. While this system will decrease
the sustained winds to a fresh breeze, it will bring strong
showers and possible thunderstorms that will bring local gales,
steep wind waves, reduced visibility and a slight chance for
waterspouts. The showers will persist Tuesday, but become more
isolated through the day while the winds continue to decrease.
Rough seas will  persist into Wednesday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 PM this evening to 5 AM PDT Monday
     for SF Bay N of Bay Bridge.

     Small Craft Advisory until 3 AM PDT Monday for Mry Bay.

     Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Small Craft Advisory until 9 AM PDT Monday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Reyes to
     Pigeon Pt 0-10 nm.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Flynn
MARINE...Flynn

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea