700
FXUS66 KMTR 140456
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
956 PM PDT Mon Oct 13 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 122 PM PDT Mon Oct 13 2025

 - Widespread rainfall and thunderstorm chances through this evening

 - Post-frontal rain showers and isolated thunderstorms tomorrow,
   tapering off by the afternoon

 - Warming and drying trend Wednesday through Saturday

&&

.UPDATE...
Issued at 845 PM PDT Mon Oct 13 2025

At the time of writing, the main frontal rain band stretches from
Napa County through the interior portions of Alameda and Contra
Costa County, across the eastern hills of Santa Clara County and
stretching across Monterey and San Benito Counties. Numerous
roadway flooding reports have come into the office, triggering the
issuance of numerous Flood Advisories across all the counties
within our area of responsibility. If there is heavy rain where
you are located, remember that it is more difficult to determine
if a road is flooded at night. "Turn around, don`t drown" is
critical advice during the daytime and even more so at night.

Selected rainfall totals as of the time of writing include 0.93
inches at the Sonoma County Airport, 0.92 inches at Napa Airport,
0.93 inches at San Rafael, 0.75 inches at downtown San Francisco,
0.89 inches at the Oakland Museum, 0.87 inches at San Francisco
International Airport, 0.50 inches in Redwood City, 1.49 inches at
San Jose International Airport, and 0.60 inches at the Monterey
Airport.

No changes to the forecast at this time.

DialH

&&

.SHORT TERM...
Issued at 122 PM PDT Mon Oct 13 2025
(This evening through Tuesday)

Rain showers have returned to the North Bay and are moving inland
across the San Francisco Bay Area. Rain showers will spread
southward across the Central Coast with increasing chances for
thunderstorms this afternoon and evening. Overall, thunderstorm
chances remain about 25% across much of the region as the atmosphere
becomes more unstable in wake of the frontal passage. CAPE values
look to range between 250-500 J/kg and lapse rates around 7 C/km
this afternoon and evening before lowering to below 250 J/kg. Ahead
of the cold front, strong and gusty winds are expected from the
southwest with gusts up to 35-45 mph in the higher terrain, gaps and
passes around the Bay Area and 40-50 mph in the higher terrain of
the Central Coast.

Post-frontal rain showers and isolated thunderstorms will continue
into the night, but the thunderstorm threat drops to around 10% or
less. However, a much colder air mass will filter into the region as
the cold core mid/upper low moves inland over the Central Coast
and/or Bay Area. However, the lack of complete clearing of clouds
may limit low temperatures Tuesday morning. Generally expecting mid
to upper 40`s inland away from the coast to lower 50`s around the
San Francisco Bayshore and along the coast. Upper 30`s will be
possible in the highest peaks across the region, especially the
Central Coast.

Rain showers may linger into Tuesday morning before tapering off by
the afternoon and especially so by the evening. Given the cold air
mass in place, afternoon temperatures will struggle to warm into the
mid 60`s. Generally speaking, temperatures look to peak in the upper
50`s to lower 60`s tomorrow afternoon.

&&

.LONG TERM...
Issued at 122 PM PDT Mon Oct 13 2025
(Tuesday night through next Sunday)

The mid/upper level low will shift east by a building shortwave
ridge nosing in from the eastern Pacific. This will result in a
gradual warming and drying trend from Wednesday through Saturday.
There has been a slight delay in the expected return of unsettled
conditions to next Monday, however cooling is still anticipated on
Sunday as a potential frontal boundary approaches. The 6-10 Day
Outlook from the Climate Prediction Center has temperatures leaning
below normal and precipitation leaning above normal.

&&

.AVIATION...
(06Z TAFS)
Issued at 955 PM PDT Mon Oct 13 2025

The main frontal band of rain, and its attendant reduced
visibilities and gusty winds, has moved into the interior portions
of the Bay Area but is still making its way through the Central
Coast. Overnight, winds will generally be light and mostly driven by
local effects, with generally VFR conditions with mid-level ceilings
possible. A chance for scattered showers and isolated thunderstorms
continues across the region through Tuesday with reduced
visibilities and gusty winds expected within and near the
thunderstorm cells. In addition, the North Bay could see steadier
light rain from the backside of the frontal system through Tuesday
morning. Otherwise, afternoon winds will be muted on Tuesday with
hints of a weak onshore flow within the models. In the post-frontal
environment, ceilings are tricky to forecast, but indications point
to generally VFR conditions with mid-level ceilings outside of the
strongest storms, barring the North Bay where MVFR ceilings could
accompany the steady rain.

Vicinity of SFO... Moderate confidence of VFR with mid-level
ceilings through the TAF period. Chance for scattered showers with
isolated thunderstorms continues through Tuesday morning, with the
main impacts being reduced visibilities and gusty winds if one
develops over the terminal. Otherwise winds will be weakly onshore
with gusts reaching 8 kt. Some divergence in the model outputs
towards the end of the TAF period with some high resolution models
pointing to southerly winds Tuesday night.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... The main rain band is expected to push out
of the terminal areas within the next couple of hours. VFR with mid-
level ceilings persists through the TAF period with light drainage
winds overnight followed by breezy west winds Tuesday afternoon.
Isolated showers and thunderstorms are possible through Tuesday
morning with the main impacts being reduced visibilities and
gusty winds if one forms or moves over a terminal.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 845 PM PDT Mon Oct 13 2025

The strongest winds and heaviest rains have moved inland, but a
chance for showers and isolated thunderstorms persists through
Tuesday morning. The showers will become more isolated while the
winds decrease overall. Rough seas to 10 feet will persist into
Wednesday, then becoming moderate through late Thursday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 PM PDT Tuesday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...DialH
MARINE...DialH

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