598
FXUS66 KMTR 141647 AAA
AFDMTR

Area Forecast Discussion...UPDATED
National Weather Service San Francisco CA
947 AM PDT Fri Aug 14 2026

...New UPDATE, MARINE...

.KEY MESSAGES...
Updated at 1101 PM PDT Thu Aug 13 2026

 - Well below normal temperatures with a deep marine layer and
   a chance for drizzle Friday

 - Gradual warming trend kicks off Saturday with temperatures
   slightly below normal into next week

&&

.UPDATE...
Issued at 945 AM PDT Fri Aug 14 2026

Overall, the short term forecast remains unchanged this morning.
24 hour temperature departures were running 5 to 7 degrees lower
thanks to plentiful cloud cover across a majority of the area.
Hourly temperatures through early afternoon were adjusted
downward to account for ongoing trends. Drizzle has persisted per
FAA and area web cams and a few more bucket tips are anticipated
along the immediate coastline through early this afternoon.
Gradual clearing is anticipated, but the timing should be similar
to what was observed yesterday based on the latest short term NWP
and trends (early to mid afternoon). MaxT remains unchanged and
I`m still anticipating today`s (Friday) highs in the 60s and 70s
with 80s across the valley locations along the US HWY 101
corridor. There`s some uncertainty across the North Bay with
respect to the clearing time as a pronounced eddy has developed
across Bodega Bay. This feature was present yesterday, however,
and areas did scatter out during the mid to late afternoon. This
seems plausible to repeat today. Onshore flow should translate to
winds accelerating through gaps and passes, with peak gusts
potentially as great as 40 mph in some of the wind corridors this
afternoon and into the pre-dawn hours on Saturday.

&&

.SHORT TERM...
Issued at 1101 PM PDT Thu Aug 13 2026
(Tonight through Saturday)

Upper-level shortwave troughing will bring the coolest conditions of
the week with well below normal temperatures and a deep marine layer
Friday. The 00Z sounding observed a marine layer of 2,400 feet with
satellite already showing an inland intrusion through the Delta and
Pacheco Pass. With the associated lift from the aforementioned
trough, drizzle can be expected along the coast and in the higher
terrain via orographic lift. Smoke from the Timber Fire is expected
to improve with the help of northwesterly transport winds.

&&

.LONG TERM...
Issued at 1101 PM PDT Thu Aug 13 2026
(Saturday night through next Thursday)

Gradual warming trend kicks off Saturday as upper-level ridging
builds into the Desert Southwest. Simultaneously, upper-level
troughing will develop well off the West Coast. This will keep the
ridge in check and onshore flow in place with temperatures remaining
below normal. The marine layer will likely be deeper in the Bay Area
than in the Central Coast with a chance for drizzle remaining across
the coast and higher terrain. Global ensemble clusters are in
agreement through Tuesday and then by Wednesday 60% show troughing
prevailing into Thursday. Sensible weather wise, this would result
in a cooling trend with increased onshore flow and the deepening of
the marine layer.

&&

.AVIATION...
(12Z TAFS)
Issued at 610 AM PDT Fri Aug 14 2026

The marine layer is around 2000-2500ft leaving the area with
widespread stratus and pockets of coastal drizzle. Cigs will take a
bit longer to clear this morning, generally by the late morning for
most sites. Breezy onshore winds return this afternoon and evening,
with another night of cloudy skies and MVFR cigs on tap. Medium to
high confidence in the forecast.

 Vicinity of SFO...Low clouds and reports of drizzle have come
across Bay Area terminals including, KSFO. Expect this to continue
through the next couple of hours, with conditions improving by mid
to late morning. The question for SFO today is whether or not the
site clears. Some models keep stratus on the western half of the TAF
ring which could leave us with SCT to BKN MVFR cigs through the
afternoon. Kept a slightly more optimistic forecast with more of the
FEW and SCT clouds, with stratus returning near or after sunset.
Medium confidence in the forecast.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...The marine layer is around 2000-2500ft
leaving the area with widespread stratus and pockets of coastal
drizzle. Cigs will take a bit longer to clear this morning, but may
struggle to actually clear at all today for KMRY.Stratus returns
early, and will likely fall to MVFR between 01-03Z. Medium
confidence in the forecast.

&&

.MARINE...
(Today through Wednesday)
Issued at 933 AM PDT Fri Aug 14 2026

Gentle to moderate northwest winds will continue through early
next week. Seas will continue to subside and become moderate in
response. A long period southerly swell of about 16 to 18 seconds
approaches the coast tonight into Sunday. Winds will freshen
early to mid next week, causing seas to build up to 9 feet. Light
drizzle is possible across the coastal waters. Haze and smoke may
also impact visibility along the Big Sur coastline due to the
Timber fire.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

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

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