642
FXUS66 KMTR 190012
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
412 PM PST Tue Nov 18 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 118 PM PST Tue Nov 18 2025

 - Mainly dry weather through Wednesday, with a few isolated showers
   being possible.

 - More beneficial type rain late Wednesday through Thursday.

 - Dry weather returns Friday and continues through the weekend.

&&

.SHORT TERM...
Issued at 118 PM PST Tue Nov 18 2025
(This evening through Wednesday)

Upper level troughing will slowly swing through southern CA today
and tomorrow, while weak upper level ridging quickly builds and then
flattens. Radar thus far has shown a few showers develop over
southern Monterey and San Benito counties, while elsewhere we have a
mix of sunny skies and fair weather cumulus. Tonight, skies should
clear and given the moisture we may see some valley fog. Tomorrow,
deterministic models suggest a weak disturbance passing over head,
which may bring some high clouds and perhaps a few isolated showers
to the region. Otherwise quiet weather prevails until the next
system approaches the PacNW. Rain chances begin to increase for the
North Bay during the evening hours.

&&

.LONG TERM...
Issued at 118 PM PST Tue Nov 18 2025
(Wednesday night through next Monday)

The aforementioned upper level low will bring a round of
beneficial rain late Wednesday into Thursday. Rainfall amounts
continue to be around 0.25" for the North Bay counties, with
perhaps slightly higher amounts in elevated terrain. Elsewhere,
amounts look to anywhere from 0.1- 0.25", with lower amounts
expected for interior locations. The Santa Cruz and Santa Lucia
mountains may see slightly higher amounts. Once this system exits
the region, ensemble and deterministic models show upper level
ridging building in for the weekend. Given additional moisture
from the rain, we should see some night and morning fog. The ridge
will also bring temperatures up a few degrees putting most areas
near or above normal.

&&

.AVIATION...
(00Z TAFS)
Issued at 349 PM PST Tue Nov 18 2025

VFR conditions with moderate diurnally driven wind dominate this
afternoon. Some low VFR cumulus clouds are gradually evaporating
across the East and South Bay. Overnight a deep but weak marine
layer will try to form, which could bring some MVFR or low VFR
clouds to the terminals by Wednesday morning. Beyond the TAF
period southerly winds will begin to increase as a cold front
approaches from the NW Wednesday night.

Vicinity of SFO...Standard afternoon moderate onshore wind will
gradually decrease through the evening. The ceiling forecast is
tricky for Wednesday. There is a good chance for a weak marine
layer to roll in early Wednesday morning, but there still a lot of
uncertainty whether it will carry clouds or if the bases will be
above or below 3,000 feet. As the day goes on cloud cover should
increase, but the ceilings will also lift. High clouds and southerly
winds will increase late in the TAF period as a cold front
approaches.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Mostly clear skies will continue through
the evening. We have another tricky forecast for Wednesday as
there is a roughly even chance for MVFR ceilings or VFR skies. SNS
has a better chance of higher ceilings and less cloud coverage
than MRY.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 349 PM PST Tue Nov 18 2025

Buoys are reporting a fresh NW breeze and rough seas. The winds
will decrease and shift to a gentle southerly breeze Wednesday,
allowing rough seas to subside and allowing for a brief favorable
weather window across the coastal waters. Late Wednesday an
approaching cold front will cause the southerly breeze to increase
to moderate before increasing and flipping back to a fresh to
strong NW breeze as the front passes early Thursday morning. The
winds will gradually diminish through the day Thursday as a very
high NW swell up to 15 feet arrives. This swell will stick around
for a while, very gradually subsiding through the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PST this evening for Pigeon Pt
     to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 3 AM PST Wednesday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Flynn
MARINE...Flynn

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