Altadena, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

551
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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