Nicasio, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

926
FXUS66 KMTR 121948
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1248 PM PDT Sat Jul 12 2025

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

.KEY MESSAGES...
Updated at 1243 PM PDT Sat Jul 12 2025

 - Near to below normal temperatures with a more notable cooling
   trend to begin Tuesday of this upcoming week.

 - Localized elevated fire weather threat continues across higher
   elevations.

&&

.SHORT TERM...
Issued at 1243 PM PDT Sat Jul 12 2025
(This evening through Sunday)

Stratus has retreated to the coast as of early this afternoon, yet a
stream continues to push through the Golden Gate, Half Moon Bay, and
around the Monterey Bay region. This is where temperatures are only
forecast to warm into the upper 50s to lower 70s this afternoon.
Across the interior, where we have pockets of Moderate HeatRisk,
temperatures will warm into the 80s and 90s with a few of the most
interior areas potentially exceeding 100 degrees F.

For tonight, look for low clouds to penetrate back inland into the
coastal valleys with the higher terrain remaining clear. As a warn
air mass remains in place aloft, minimum temperatures are forecast
to remain in the 60s to 70s in the peaks and higher ridgelines.
Elsewhere, with around a 1500 foot marine layer, temperatures will
generally be in the 50s into Sunday morning. There remains the
potential for coastal drizzle and/or mist overnight into Sunday
morning, yet not expecting enough coverage to put in the official
forecast.

For Sunday, expecting a near repeat of today. Onshore winds will
increase slightly by the afternoon and continue into the evening
before easing after sunset.

&&

.LONG TERM...
Issued at 1243 PM PDT Sat Jul 12 2025
(Sunday night through next Friday)

A slight cooling trend will return by Tuesday with temperatures
holding steady for the remainder of the week, of course with the
typical diurnal trend. These maximum temperatures will be anywhere
between 5-15 degrees below seasonal averages across the interior.
The marine layer is forecast to deepen a bit as we move into late
week which will likely lead to increase/further inland penetration
of stratus into the coastal valleys each night. This will be as an
upper level ridge surrounds most of the region, while a quasi-
permanent shortwave through is embedded in the ridge aloft.

&&

.AVIATION...
(18Z TAFS)
Issued at 1016 AM PDT Sat Jul 12 2025

Currently a mixed bag of LIFR-VFR at the terminals. High confidence
in all terminals deteriorating to sub-VFR conditions tonight with
the exception of LVK which only has a 20% probability. Smoke from
wildfires burning in Northern California will likely filter into the
region and reduce slight range visibilities.

Vicinity of SFO...Currently VFR with northeasterly flow. Westerly
flow will return once the sea breeze kicks in this afternoon. High
confidence in sub-VFR ceilings returning tonight, likely on the
cusp of IFR/MVFR.

SFO Bridge Approach...The approach still has some low stratus this
morning, but that should evaporate very quickly. Low stratus clouds
will begin to filter in through the Golden Gate Gap by 01Z with
visuals likely being impacted through 18Z Sunday.

Monterey Bay Terminals...Currently IFR and calm at both terminals.
Both terminals are expected to improve to VFR shortly with stratus
sticking to the coast during the day. High confidence in LIFR
ceilings returning to both terminals tonight.

&&

.MARINE...
(Today through Thursday)
Issued at 859 AM PDT Sat Jul 12 2025

A gentle to moderate breeze with moderate to rough seas will
prevail through Wednesday. Localized hazardous marine conditions
will continue through Wednesday for far northwestern portions of
the northern outer waters with strong northerly breezes and very
rough seas at times.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Sarment
MARINE...Sarment

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