Corte Madera, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

717
FXUS66 KMTR 302113
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
113 PM PST Mon Dec 30 2024

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

.SYNOPSIS...
Issued at 112 PM PST Mon Dec 30 2024

Generally dry and cold conditions continue through the next few days
with Freeze Warnings and Frost Advisories across the region tonight.
Light rain possible late Thursday into Friday.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 112 PM PST Mon Dec 30 2024

Satellite imagery shows generally clear skies throughout the region
in the wake of the cold front that came through yesterday. High
temperatures today range from the upper 50s to lower 60s in the
lower elevations to the upper 40s to middle 50s in the higher
elevations. Winds will be light throughout the day with a faint
northwest flow.

Tonight`s low temperatures presented a forecast challenge for the
operations team. Yesterday`s forecast for low temperatures this
morning was far colder than the actual observations, so the
operations team focused their forecast on the low temperatures for
the next couple of days. The eventual consensus was a blend of the
deterministic NBM and the 25th precentile from the NBM ensembles,
which tamped down temperatures a couple of degrees from last night`s
forecast. The resulting forecast calls for low temperatures in the
lower to middle 30s in the inland valleys, into the upper 30s to the
lower 40s in the coastal and Bayshore regions. Even then, confidence
in low temperatures is somewhat lower than typical. Look onto the
coastal waters and you`ll see feathered bands of high clouds trying
to come into the Bay Area and Central Coast. The current forecast
has high cloud cover expanding across the region through the day,
and while they do clear out during the evening and overnight hours,
where the cloud coverage does linger later into the night, or where
fog develops (as is possible in parts of the North Bay), radiational
cooling might be inhibited and keep temperatures warmer than the
current forecast.

A Freeze Warning for the interior North Bay, the eastern Santa Clara
Hills, and the interior Central Coast, and a Frost Advisory for the
rest of the region barring the city of San Francisco and the Pacific
coast of the San Mateo Peninsula, will be out from 8 PM this evening
to 10 AM tomorrow morning. To prepare for these cold temperatures,
remember the Four P`s of Winter Weather:

People: Dress in layers and wear a hat that covers the ears. Pay
special attention to children and the elderly, who are more
vulnerable to the cold.
Plants: Bring potted plants indoors and keep outdoor plants and
trees protected.
Pets: Bring all pets indoors. Pets and other animals that have to be
kept outdoors should have an enclosed shelter.
Pipes: Make sure all external water pipes are insulated. Keep an
interior faucet running at a drip to prevent ice buildup.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 112 PM PST Mon Dec 30 2024

Low temperatures will warm up by a couple of degrees on the night of
New Year`s Eve into the morning of New Year`s Day. The operations
team considered issuing cold weather products for said night, but
due to lower confidence in the low temperature forecast, ultimately
decided to hold off. For example, the Sonoma County valleys are
practically guaranteed to see temperatures below freezing at some
point tonight, but on the night of New Year`s Eve, that probability
drops to as high as 60-70%, with possible high clouds decreasing
confidence in the forecast. Even so, the temperatures are still
anywhere between 3 to 10 degrees below seasonal averages across the
inland valleys, with potentially impactful consequences for
vulnerable populations, including children, the elderly, and people
without access to adequate heating or shelter.

Speaking of high clouds, they are expected to start building in the
evening of New Year`s Eve, but the low stratus that would be a more
potent threat to firework watching on that night won`t be very
widespread. Temperatures at midnight range from the middle 30s to
lower 40s around the inland valleys, to the middle 40s to near 50
closer to the coast and Bayshore.

Some light sprinkles are possible in parts of the North Bay on
Wednesday, the very fringe of a larger system that primarily targets
northern California and the Pacific Northwest. Probabilities of
precipitation top out at 40-50% across the coastal ranges of Sonoma
County, where the forecast rainfall total maxes out at around a
tenth of an inch. Rainfall chances decrease dramatically farther
south, with around a 20% chance of rain in Santa Rosa, and a 10%
chance of rain near Napa and San Francisco. Otherwise, temperatures
start a warming trend on Wednesday and Thursday, before the next
chance for widespread light rain comes in late Thursday into Friday
with the fringes of another system that`s focused on the areas to
the north. The current forecast calls for rainfall totals a quarter
to half an inch of rain in the North Bay valleys and a tenth to a
quarter of an inch across the Bay Area.

CPC outlooks suggest a lean towards temperatures above seasonal
averages and precipitation totals below seasonal averages heading
into the second week of January.

&&

.AVIATION...
(18Z TAFS)
Issued at 957 AM PST Mon Dec 30 2024

Patchy fog is lingering in the vicinity of LVK but satellite shows
that fog coverage is actively diminishing and is expected to
dissipate by 19Z at the latest. Winds generally remain light through
the period with NW winds persisting at most sites through the
afternoon before becoming more N to E/NE during the
evening/overnight. Generally VFR through the TAF period but fog
becomes more likely again overnight for STS, APC, and LVK. LAMP
probability guidance and ensemble guidance point towards a higher
likelihood of fog developing after 10/11Z but visibilities will
start dropping as early as 09Z. Conditions should start to improve
around 17-18Z tomorrow with fog dissipating close to the end of this
TAF period/beginning of the next TAF period.

Vicinity of SFO...VFR through the TAF period. Light winds, generally
out of the NW, with high level clouds.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period but slight
decreases in visibility are possible at SNS overnight. Winds
generally remain light with more easterly winds expected during the
early morning/overnight hours and more northwesterly winds expected
during the afternoon. Ensemble guidance shows some fluctuations in
visibility overnight at and in the vicinity of SNS with most keeping
visibilities above 6SM. Moderate confidence that visibilities will
not drop below 6SM at SNS but temporary lower fluctuations may
occur.

&&

.MARINE...
(Today through Saturday)
Issued at 859 AM PST Mon Dec 30 2024

Fresh northwest winds will prevail across the coastal waters into
the New Year. Breezy winds and rain will arrive ahead of a cold
front for the northern waters. The cold front will move eastward
taking the rain with it as well later Friday. Moderate to long
period swell will continue to run underneath the wind driven
waves.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory from 8 PM this evening to 10 AM PST Tuesday for
     CAZ502-503-505-508-510-512-513-515-529-530.

     Freeze Warning from 8 PM this evening to 10 AM PST Tuesday for
     CAZ504-506-514-516>518-528.

PZ...Small Craft Advisory until 3 AM PST Tuesday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt
     Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 AM PST Tuesday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

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

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