Forest Knolls, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

493
FXUS66 KMTR 062003
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1203 PM PST Sat Dec 6 2025

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1200 PM PST Sat Dec 6 2025

 - Benign conditions through the next seven days with no
   precipitation expected and a gradual warming trend

 - Impacts from Tule Fog continue in the North Bay and interior
   East Bay valleys, with potential for expansion across the rest
   of the Bay Area tonight

 - Next chance for rain towards the middle of the month

&&

.SHORT TERM...
Issued at 1200 PM PST Sat Dec 6 2025
(This evening through Sunday)

The current satellite image shows dissipating stratus across the
Santa Clara Valley and the San Francisco Bay Shoreline, while the
City and the valleys of the North Bay and interior East Bay remain
socked in the spillover from the Tule Fog across the Central Valley.
Towards the western parts of Sonoma and Marin counties, the Tule Fog
spillover merges with marine layer stratus. The trend of the last
couple of days has been the models struggling to accurately reflect
the evolution of the Tule Fog in the North and East bay valleys.
Model output shows the stratus deck beginning to dissipate over the
North Bay valleys now, but that does not appear to be happening. I
have tamped down the highs for today and tomorrow across the Bay
Area in response to the model`s struggles. The current forecast has
today`s highs in the upper 50s across the Bay Area valleys, with
central and eastern Contra Costa County and far eastern Alameda
County seeing highs in the lower to middle 50s. This does assume
that the stratus does eventually mix out this afternoon, and if
the stratus lingers through the day, the North and East bay
valleys might not get out of the 40s. Tomorrow`s forecast
currently has the highs warming by a couple of degrees, within a
couple degrees of 60 for most of the area, but this is highly
dependent on how the Tule Fog evolves tonight into Sunday morning,
and could also need to be dropped if the stratus sticks around
long enough tomorrow.

Meanwhile, over in the Central Coast the skies are clear, have
remained generally clear this morning, and will remain clear during
the afternoon and evening hours. Model output is showing some
possibility for stratus to develop in the Monterey Bay region and
northern Salinas Valley tonight. While is some reason to second-
guess the model output, for the reasons stated above, those reasons
lean towards more stratus being present than the current forecast.
However, any influence from the Tule Fog will be limited to the far
eastern reaches of San Benito and southern Monterey Counties, where
the Gabilan Range abuts the Central Valley. Highs in the Central
Coast reach the middle to upper 60s in the inland valleys, to the
lower to middle 60s closer to Monterey Bay, perhaps into the lower
70s in some of the sheltered valleys within the Santa Lucia and
Gabilan ranges.

&&

.LONG TERM...
Issued at 1200 PM PST Sat Dec 6 2025
(Sunday night through next Friday)

Ridging will dominate the weather patterns through the rest of the 7-
day outlook, enabling a gradual warming trend across the region. The
highs will peak around the later part of the upcoming work week with
highs in the inland valleys reaching the middle 60s to middle 70s,
around 8 to 13 degrees above the seasonal average. As with the short
term forecast, the biggest source of uncertainty will be how the
Tule Fog develops every night and morning, impacting the
temperatures across the North and East Bay valleys. The
deterministic forecast has the East Bay interior valleys remaining
in the lower to middle 60s, but depending on how the Tule Fog
evolves the temperatures could easily vary by around 10 degrees on
either side of the current forecast.

A couple of storm systems will approach the West Coast during the 7-
day outlook, but the ridging pattern will deflect the brunt of the
storms to the Pacific Northwest and leave us with a chance of
drizzle in the coastal waters while land areas remain dry. Longer
range model guidance suggests a possible change in the weather
pattern towards the middle of the month. Ensemble model cluster
analysis continues to show some of the model members (somewhere
around 30-40% of the ensemble members) depicting a breakdown of the
ridge. however, most of the ensemble members and the ensemble means
point to the ridge persisting over the western United States, or
flattening out into a zonal flow pattern. Uncertainty remains rather
high in this part of the forecast and we will keep an eye on what
the trend from later model runs turns out to be.

&&

.AVIATION...
(18Z TAFS)
Issued at 940 AM PST Sat Dec 6 2025

LIFR to IFR conditions across much of the Bay Area this morning,
while VFR conditions prevail at the Monterey Bay terminals. Low
ceilings and/or visibilities are forecast to improve by around 20Z
and give way to mostly VFR conditions. Onshore winds increase by
mid- to-late afternoon across the San Francisco Bay and Monterey
Bay terminals. High confidence for low ceilings and/or
visibilities for the North Bay and East Bay with moderate
confidence for the Bay Area terminals late tonight through Sunday
morning. Moderate to high confidence for VFR conditions to prevail
through much of that TAF period for the Monterey Bay terminals.
Low clouds and/or fog look to improve by midday Sunday.

Vicinity of SFO...IFR conditions across much of the region this
morning. Conditions are forecast to improve by 19Z-20Z and give
way to VFR throughout the remainder of the afternoon. Moderate
confidence for IFR conditions to return either late tonight or
early Sunday morning as wind speeds turn more offshore. Onshore
winds are forecast by Sunday afternoon with VFR conditions.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period. Light to
southerly winds prevail this morning and are forecast to become
onshore by early-to-mid afternoon. Winds diminish overnight and
become southerly early Sunday morning.

&&

.MARINE...
(Today through Thursday)
Issued at 845 AM PST Sat Dec 6 2025

Fresh northwesterly winds persist through this weekend and into
the middle of next week. Strong to near gale force gusts will be
possible through this weekend. Moderate seas with wave heights 6
to 8 feet across the outer waters this weekend. A new, long period
northwesterly swell is anticipated by Wednesday of next week.

&&

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

PZ...Small Craft Advisory from 3 PM to 9 PM PST Sunday for Pigeon Pt
     to Pt Pinos 0-10 nm.

     Small Craft Advisory until 9 PM PST this evening for Pt Pinos to
     Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory from 9 AM Sunday to 3 AM PST Monday for Pt
     Pinos to Pt Piedras Blancas 0-10 nm.

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

     Small Craft Advisory from 9 AM to 9 PM PST Sunday for Pigeon Pt
     to Pt Pinos 10-60 NM.

&&

$$

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

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