San Mateo, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

116
FXUS66 KMTR 051150
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
350 AM PST Fri Dec 5 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 303 AM PST Fri Dec 5 2025

 - Hazardous cold conditions through Friday morning for North and
   East Bay Valleys and interior Central Coast

 - Persistent forecast through the next seven days with benign
   conditions and no precipitation expected

 - Impacts from Tule Fog continue in the interior East Bay

&&

.SHORT TERM...
Issued at 315 AM PST Fri Dec 5 2025
(Today and tonight)

First and foremost expanded the Cold Weather Advisory to include
the North and East Bay Valleys with the existing advisory over
the Interior Central Coast. A lot less mid-hgih level clouds are
being observed overnight. The clear skies combined with relatively
light winds increased radiational cooling effectiveness
overnight. As such, seeing a lot more observations around that 36
degree threshold. Therefore, went ahead and expanded the Cold
WEather Advisory. Also seeing some radiational fog form over the
North Valleys with patchy dense fog near Santa Rosa. Additionally,
the Central Valley is still seeing some Tule Fog. Just like the
last few nights it will creep into the West Delta and far interior
East Bay Valleys.

Otherwise, the large area of upper level high pressure parked off
the CA will slowly ooze eastward. At the same time a few weak
systems will ride the north periphery of the ridge and move
through the PacNW. These weak system will bring some clouds and
decaying fronts over the NorCal Coast. Previous forecast had a
mentions of showers over the coastal waters today and tonight, but
it`s looking less likely. Hi-res guidance is still picking up on
some moisture. In stead of completely removing the precip
converted it to drizzle. Regardless, no impact to land and kept
all chances over the waters.

Sensible weather today will be rather pleasant after the cool
start. Highs today will be mainly in the 60s. For tonight,
expecting less radiational cool due to some increasing clouds and
possible return of low stratus. Will hold off on extending any
Cold Weather Advisories tonight.

&&

.LONG TERM...
Issued at 320 AM PST Fri Dec 5 2025
(Saturday through Thursday)

Pretty benign weather through the long term. The ridge of high
pressure will keep the region high and dry with the exception of
drizzle over the coastal waters this weekend. The ridge of high
pressure is expected to build and strengthen over CA into early
next. As such, additional warming is expected with a general 2 to
4 degrees through the middle of next week. In fact, by next
Wednesday/Thursday interior Central Coast is forecast to reach the
mid 70s with solid 60s to near 70 elsewhere around the Bay Area.

How about rain? Longer range guidance still shows a possible
pattern change by the middle of the month. Cluster analysis of
ensembles show a majority still keeping a ridge, but a few
cluster groups show a breakdown of the ridge. FWIW CPC 8-14 day
outlook is now showing increasing chances for precip Dec 12-18.

&&

.AVIATION...
(12Z TAFS)
Issued at 349 AM PST Fri Dec 5 2025

Patches of fog and low clouds are affecting portions of the North
Bay and the East Bay. Expect mostly light to moderate winds through
the morning with fog and lower clouds clearing into the mid to late
morning. Winds increase turn northwest into the afternoon for all
but the North Bay and East Bay, which will see southerly and
easterly winds. Expect winds to reduce into the evening and
overnight with fog and low clouds building along the coast and
interior valleys later into the night.

Vicinity of SFO...VFR through the TAF period. Light and variable
winds last into the afternoon. Expect winds to turn northwest and
become moderate in the mid to late afternoon, and reduce into the
late night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period. Light to
moderate easterly winds last through the afternoon before becoming
northwesterly . Winds weaken and become light into the evening.
Southeast drainage winds look to affect SNS into the late night,
while winds at MRY stay light and variable.

&&

.MARINE...
(Today through Wednesday)
Issued at 305 AM PST Fri Dec 5 2025

Winds are building across the waters with fresh to strong gusts
expected. These winds persist into the work week. Localized near
gale force gusts are possible across the outer waters through
Saturday. Moderate seas continue with seas building to between 6
to 8 feet Friday through Sunday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 3 PM PST Sunday for CAZ006-506-508-
     529-530.

     Cold Weather Advisory until 8 AM PST this morning for CAZ506-510-
     516-518.

PZ...Small Craft Advisory from 9 AM this morning to 3 AM PST Saturday
     for Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory from 3 PM this afternoon to 3 AM PST Sunday
     for Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 9 PM PST Saturday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PST Sunday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...Murdock
MARINE...Murdock

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