FXUS66 KMTR 042349
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
349 PM PST Thu Dec 4 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1139 AM PST Thu Dec 4 2025

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

 - Hazardous cold conditions continue in the interior Central
   Coast Friday morning

 - Impacts from Tule Fog continue in the interior East Bay

&&

.SHORT TERM...
Issued at 1139 AM PST Thu Dec 4 2025
(This afternoon through Friday)

Satellite imagery shows lingering stratus in the interior East Bay, 
an outgrowth of the Tule Fog across the Central Valley, and the very 
southern portion of the Salinas Valley. Isolated patches of higher 
clouds are scattered across the region. The general weather pattern 
continues to be dominated by ridging in the eastern Pacific, which 
has been edging into the western United States after a trough pulled 
away into the Central United States. The large scale flow continues 
to come from the north, and generally mild offshore flow persists 
across the higher elevations of the Bay Area, although as the 
offshore gradient begins to significantly weaken, the offshore flow 
will likewise decrease. Expect another round of Tule Fog impacts 
tonight into Friday morning, mainly across the interior Bay Area 
with potential impacts in the North Bay valleys.

Highs today range from the upper 50s to the middle 60s across the 
lower elevations, except in the interior East Bay where highs remain 
in the lower 50s. A Cold Weather Advisory remains in effect for the 
interior Central Coast, including the southern Salinas Valley, for 
the midnight to 8 AM timeframe on Friday morning, as lows reach the 
lower to middle 30s generally and down into the 20s for isolated 
locations in the higher elevations. Elsewhere, lows range from the 
lower to middle 40s in the lower elevations, reaching into the upper 
40s in the higher elevations. Temperatures in the interior East Bay 
are expected to warm slightly tomorrow into the lower 60s, while the 
rest of the region sees highs around 1 to 2 degrees warmer than 
today's.

&&

.LONG TERM...
Issued at 1139 AM PST Thu Dec 4 2025
(Friday night through next Wednesday)

The forecast conditions remain so stable that a lot of my discussion 
from yesterday still applies. We are still expecting the ridging to 
build into the southwestern US, promoting a gradual warming trend 
through the early part of next week with the inland valleys reaching 
the upper 60s to middle 70s. We are still expecting a couple of 
storm systems to get deflected into the Pacific Northwest and leave 
us with offshore showers, potential light drizzle in the Sonoma 
coastal ranges, and disappointment for fans of wet weather 
everywhere else. We are still seeing the next chance for widespread 
rain towards the middle of the month with very high levels of 
uncertainty for that part of the forecast.

&&

.AVIATION...
(00Z TAFS)
Issued at 349 PM PST Thu Dec 4 2025

VFR everywhere except STS and LVK. Guidance is showing some 
potential for fog to develop across the interior East Bay Valleys 
and North Bay Valleys tonight. For STS, fog chances increase after 
12-14Z. Confidence wasn't high enough to put dense fog just yet but 
added in visibilities trending lower to around 3SM around 14Z. For 
LVK, leaned more towards lower visibilities around 3SM impacting LVK 
overnight with guidance not showing visibilities below 3SM at the 
airport. Winds are generally light and offshore but there may be 
another round of breezy offshore winds during the morning hours 
again along the coast. Moderate confidence that we will see all 
sites switch back to onshore by tomorrow afternoon as the the SFO-
WMC gradient becomes positive again and strengthens.

Vicinity of SFO...VFR through the TAF period. A weak sea breeze may 
develop late this afternoon/evening before light offshore flow 
returns overnight. Confidence is higher that we'll return to our 
more typical moderate afternoon sea breeze pattern by tomorrow 
afternoon as the SFO-WMC gradient strengthens and becomes positive 
again.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Winds generally remain light through 
the TAF period. Winds generally stay onshore during the day before 
becoming lightly offshore overnight. Drainage winds out of the SE 
are expected at SNS with winds peaking around 10-12 knots tomorrow 
morning.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 349 PM PST Thu Dec 4 2025

A light to moderate northerly breeze will persist over the coastal
waters through Thursday night with generally low seas. Winds will
increase on Friday with strong gusts in the offshore and the
northern most nearshore waters along with building seas up to 8
feet by Friday night. Breezy and at times gusty winds will prevail
into next week.

&&

.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 Friday for CAZ516-518.

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

     Small Craft Advisory from 9 PM this evening to 3 AM PST Saturday 
     for Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 3 AM Friday to 3 AM PST Saturday for 
     Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Kennedy
MARINE...RGass

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Prepared by Boulder-Creek.com Weather at: Thu Dec 4 18:30:02 PST 2025