162
FXUS66 KMTR 190529
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
929 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.

&&

.UPDATE...
Issued at 833 PM PST Tue Nov 18 2025

An upper level low will remain located over southern California
tonight into Wednesday while high pressure moves in across our
forecast area from the northwest. High pressure will bring dry
weather along with night-time radiative cooling resulting in patchy
fog during the overnight and Wednesday morning. Newly arriving 00z
forecast guidance agrees with previous guidance that the dry weather
break will be temporary. Another low pressure system is forecast
to arrive from the northwest later Wednesday, Wednesday night and
Thursday bringing more wet weather to our forecast area. For additional
info on the forecast please see the previous discussions.

&&

.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...
(06Z TAFS)
Issued at 918 PM PST Tue Nov 18 2025

Low clouds are moving in from the coast, driven by a mesoscale low
pressure system near Bodega Bay. These clouds will impact many
terminals with MVFR ceilings overnight, but they should help limit
fog formation. Towards the end of the TAF period southerly winds
will begin to increase as a cold front approaches from the NW
Wednesday night.

Vicinity of SFO...Winds have decreased to a gentle onshore breeze
and the terminal has dodged ceilings for now. As the night goes
on, the chance for high MVFR or low VFR ceilings increases,
particularly in the hours around sunrise. If these ceilings form,
they will lift in the late morning. It now looks like southerly
winds will persist through the majority of the TAF period once
they become established. The cold front will bring another round
of lower ceilings and some light rain late in the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...A small pesky patch of stratus at MRY is
making the short term forecast challenging. While the ceilings may
clear in the short term, the overall trend is for a more robust
area of stratus to move over the terminal early Wednesday morning.
The ceiling height is a little uncertain but should be somewhere
between FL 015 and 050 through the majority of the TAF period
before the low clouds start to clear Wednesday afternoon. The cold
front will bring some light rain here as well, but it`s outside of
the current TAF window.

&&

.MARINE...
(Tonight through next Monday)
Issued at 918 PM PST Tue Nov 18 2025

Buoys are reporting a moderate northerly breeze and rough seas.
The winds will shift to a gentle southerly breeze Wednesday,
allowing rough seas to subside for a brief favorable weather
window. 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 3 AM PST Wednesday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory from 3 AM to 9 AM PST Thursday for Pt Arena
     to Pt Reyes 10-60 NM.

&&

$$

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

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