780
FXUS66 KMTR 071050
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
350 AM PDT Tue Oct 7 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.KEY MESSAGES...
Updated at 344 AM PDT Tue Oct 7 2025

 - Cool at the coast, while everywhere else sees the warmest
   temperatures of the forecast today.

 - Cooler and cloudier for Wednesday

 - Drizzle and light rain arrives into the second half of the week

&&

.SHORT TERM...
Issued at 344 AM PDT Tue Oct 7 2025
(Today and tonight)

Low clouds have been moving up from the Central Coast and have
filtered into the Monterey Bay. This is looking like a weak
"Southerly Surge" pattern, but is enough to warrant some adjustments
to the today`s high temperatures along the coast. That being said,
today will still be the warmest day of the forecast for most. The
cloud covered coastal areas will struggle to make it out of the 60s
while the areas slightly inland and exposed to the clear skies will
quickly climb. This will result in some tight temperature gradients,
for example: Oceanside Sanfrancisco looks to peak in the mid 60s,
while eastern San Francisco looks to peak around just under 85
degrees. The warmest of the warm will be in the higher elevations in
the interior where the mid 90s are not out of the question.

Interior temperatures will be quick to cool after sunset, falling
into the mid to low 50s for most areas, with some 40s in the far
interior portions of Monterey Co. Patches of fog and chances for
drizzle arrive to the Monterey Bay into the late night, signaling
the start of quite the pattern change.

&&

.LONG TERM...
Issued at 344 AM PDT Tue Oct 7 2025
(Wednesday through Monday)

Wednesday will be a big pivot in conditions as onshore flow, marine
layer influence, and more persistent cloud cover will call for a
much cooler day across the region. Expect the coast to remain in the
60s while the inland areas mostly stick to the 70s and only a few of
the interior areas break into the 80s. Cloud cover will be quick to
rebuild into the evening as the approaching low pressure allows the
marine layer to expand and the increased onshore flow will push
moisture into that expanded marine influence. Additionally, near
term models are showing good confidence on drizzle to pockets of
light rain arriving to the coast and the Bays into Wednesday night
and building into Thursday morning.


Drizzle chances will turn to light rain chances for the North Bay
into Thursday and chances look to spread farther south and east into
that evening. While rain chances look to spread as far south as the
Monterey Bay, the rain will mostly be focused in the northern
portions of the CWA. As of the current forecast, the highest amounts
of rainfall look to be the northernmost portions of the mountains on
the Sonoma Coast, with around a third of an inch between Thursday
evening to early Saturday. The SF Bay itself looks to see less than
a tenth of an inch, and these amounts get less and less the farther
south and east you look. This is also over a fair amount of time, so
most of the rainfall looks to be unimpactful. Some models are
entertaining the possibility of isolated thunderstorms in the far
northern portions of Sonoma Co into Friday afternoon, but these
chances cap off around 12%.

Models and longer term ensembles show some potential for this low
pressure to slow into the weekend, which could allow rain chances to
exit further into Saturday. This doesn`t look to add much to the
over all rainfall totals, though. Onshore flow and the building of
a cooler airmass will allow for conditions to remain cool through
the weekend.

Models diverge into the next work week, but most are calling for
additional rains. The transport of these rains varies as the
movements of additional troughing and low pressures are in poor
agreement amongst the long term models. It looks like the models
are struggling, which is kind of typical for long term forecasts in
the shoulder seasons. It will be interesting to see how the models
continue to evolve and resolve.

&&

.AVIATION...
(12Z TAFS)
Issued at 344 AM PDT Tue Oct 7 2025

It`s VFR except satellite and surface observations show areas
of fog and stratus /IFR-LIFR/ moving northward along the coast.
The marine layer depth remains near or at sea level under thermal
ridging aloft. Fog and stratus will continue to advance northward
through the morning, the early October sun mixing out some of the
fog and stratus otherwise an inland intrusion of fog and stratus
is likely tonight and Wednesday morning.

Vicinity of SFO...VFR through today, stratus /IFR/ developing early
Wednesday morning. Light northeast wind this morning becoming west
to northwest 10 to 15 knots this afternoon and early evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Satellite and surface observations show
areas of fog and stratus /IFR-LIFR/ around the Monterey Bay. A
southerly wind reversal will bring a northwest wind to KSNS and a
southwest wind to KMRY today. Fog and stratus will mix out in the
afternoon, however fog and stratus /IFR/ will return tonight and
Wednesday morning.


&&

.MARINE...
(Today through Sunday)
Issued at 344 AM PDT Tue Oct 7 2025

Expect mostly light to moderate winds accompanied by low to
moderate seas will prevail through early Wednesday before winds
begin to build in the northern outer waters. Winds and seas
continue to increase in the mid week and again into the next work
week. Drizzle chances affect the waters Wednesday and Thursday
with chances for light rain affecting the northern waters late
Thursday through early Saturday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM to 9 PM PDT Wednesday for Pt
     Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...Canepa
MARINE...Murdock

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