Calistoga, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

557
FXUS66 KMTR 180554
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
954 PM PST Fri Jan 17 2025

...New AVIATION...

.SYNOPSIS...
Issued at 233 PM PST Fri Jan 17 2025

Cool weather continues with coastal and valley fog to return again
tonight. A Frost Advisory will be in effect from 1 AM to 9 AM
Saturday morning for portions of the interior Central Coast. Gusty
offshore winds remain likely Monday into Tuesday with peak gusts
between 35 to 40 mph across the interior North Bay Mountains.

&&

.UPDATE...
Issued at 857 PM PST Fri Jan 17 2025

Evening satellite imagery looks more like June than January. The
pesky marine layer from the afternoon continues to fill in across
the inland valleys and along the immediate coast. Ft Ord profiler
puts the depth near 1500-2000 feet. Taking a closer look at
temperatures - all depends on your cloud cover. Areas under the
marine layer are running warmer than yesterday evening and areas
with clear skies are running colder than yesterday evening for the
most part. The Frost Advisory does remain in effect for interior
Central Coast tonight with the coldest temperatures near the SLO
county line. Even if you`re not in the Frost Advisory tonight it
will still feel cold. The marine layer will bring damp conditions
and with temps in the 35-40 degree range it will feel cold,
especially those without adequate shelter.

No update needed for tonight.

Saturday will begin with a cloudy/foggy start giving way to
afternoon sunshine.

Additional frost/freeze products will likely be needed Saturday
night into Sunday.

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 233 PM PST Fri Jan 17 2025

Cooler daytime temperatures are being observed with most locations
still in the low to mid 50s as of 1PM. This is the result of
widespread persistent stratus across the Bay Area and Central Coast
which is preventing solar radiation from reaching the ground,
resulting in less surface warming than would be observed if cloud
cover had dissipated earlier. Although stratus coverage is
dissipating, if you were hoping for a much warmer day you are
unfortunately not in luck. With the 11AM forecast update, high
temperatures were lowered by a few degrees, due to the prolonged
overcast skies, with most sites expected to only reach into the mid
to upper 50s today. The warmest portions of the Santa Clara Valley
and interior Central Coast may push into the low 60s. Cooler morning
temperatures continue again Saturday morning across the interior.
Most interior Bay Area locations will see lows in the upper 30s
(just above frost advisory criteria) while the interior Central
Coast will see temperatures in the low to mid 30s. As such, a Frost
Advisory will be in effect from 1 AM to 9 AM on Saturday for
portions of interior Monterey and San Benito Counties. Overcast,
foggy conditions are expected to return again tonight with fog
likely to develop throughout the valleys and across portions of the
coastline.

Vicinity of Moss Landing: the strongest winds (10 to 15 mph) are
expected to continue through the afternoon hours and will be out of
the west. The stronger winds means that smoke will be dispersed over
a wider horizontal distance to the east of Moss Landing. This means
smoke impacts will be felt over a wider region with the area between
Moss Landing and Prunedale looking to be the most impacted. Areas
between Prunedale to Hollister are within the smoke plume in hysplit
model guidance but impacts to these areas will be lower than those
observed closer to Moss Landing. Looking ahead to this evening, the
wind direction will shift from out of the west to out of the
northeast. This will cause light smoke concentrations to linger
around the Monterey Bay region, potentially leading to impacts in
the Northern Salinas Valley and areas in southeast Santa Cruz
County. Residents in the impacted area should adhere to all guidance
from public officials, keep all windows shut, and turn off air
conditioners and any systems that circulate air from the outdoors to
the indoors. Please refer to your local air quality management
district (Monterey Bay Air Resources District) for the air quality
forecast.

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 233 PM PST Fri Jan 17 2025

Model guidance continues to highlight the chance for gusty northeast
winds to develop across the North Bay (particularly interior North
Bay Mountains) Monday into Tuesday as upper level troughing builds
in across the Central United States. Ensemble guidance has started
to agree on a moderate to strong offshore pressure gradient
developing during this timeframe but there are still variations as
to how strong the gradient will be. For example, the SFO-WMC
pressure gradient shows the gradient peaking as low as -18.6 mb or
as high as -6.3 mb at noon on Monday. So while confidence is
increasing that we will see offshore winds, the exact magnitude of
these winds is still fluctuating. For now, peak gusts continue to
look between 35 to 40 mph and are centered over the interior North
Bay Mountains with isolated stronger gusts possible at the highest
elevations and ridgetops. Occasional strong gusts are possible in
the East Bay Hills and portions of the Santa Cruz mountains where
occasional gusts between 20 to 30 mph may be possible. Fire concerns
remain low, however, with early winter rains having helped to raise
fuel moisture levels across the North Bay and rest of the Bay Area.

A gradual warming trend is expected beginning early next week with
daytime temperatures warming back into the 60s. Similarly, morning
temperatures will remain chilly through Thursday but most locations,
excluding the interior Central Coast, should stay above Frost
Advisory criteria. Lows will generally be in the upper 30s to low
40s for most of the coast and Bay Area but lows will be closer to 30
across the interior Central Coast. For those who are interested in
our rain chances, NBM guidance has started showing some potential
for precipitation beginning next Friday with longer term guidance
highlighting a potential storm starting late Friday through Monday.
ECMWF and GFS guidance both show some sort of system developing the
25th to 27th but ensembles remain split on if we will receive any
rain from it. The consensus is that any rain that does develop looks
to be fairly light across our area with the ECMWF deterministic
showing most of the rain moving over southern California. At the
same time, guidance is suggesting gusty winds may develop as the
system moves through the region but confidence in exact speeds is
low given how far away the event is. Keep checking back to stay up
to date on how this system shapes up as we get closer to this
event.

&&

.AVIATION...
(06Z TAFS)
Issued at 954 PM PST Fri Jan 17 2025

Surface observations continue to show a mix of VFR-MVFR across
the forecast area except LIFR has developed at KSTS. Light onshore
breezes continue, the SFO-SAC pressure gradient remains at 0.9 mb.
Surface to near surface transport of cooler air has weakened or
lifted the lower level temperature inversion per recent profiler
data. Fort Ord profiler shows a weak lower level temperature
inversion based near 2700 feet, the Oakland upper air sounding
late this afternoon showed a 2000 feet base of the temperature
inversion. A weak and dry cool front will slide southward and
stall along the Monterey Bay later in the evening and overnight.

Overall conditions are favorable for continuing redevelopment of
low clouds /MVFR-IFR/ ahead of and behind the weak embedded cool
front tonight and Saturday morning. Patchy fog /VLIFR-IFR/ will
develop too, best chances for development will be over the inland
valleys due to night-time radiational cooling to saturation.

High resolution models show low clouds and fog lingering Saturday
morning, though a drying, continental, cold air drainage southeasterly
wind flow will develop overnight in the Salinas Valley. This may
bring a return to VFR earlier across northern Monterey County
relative to the Bay Area later clearing Saturday morning. A caveat
is smoke and haze from the ongoing fire at Moss Landing will tend
to reduce surface and slant range visibility.

Surface high pressure builds over the Great Basin tonight and
Saturday, resulting in offshore winds and drying, limiting the
areal coverage of low clouds Saturday evening/night per recent
HREF output.

Vicinity of SFO...A west wind transported low clouds to SFO this
evening. MVFR continues tonight and Saturday morning to 18z. West
wind diminishing tonight and Saturday morning to light easterly
wind, then northwesterly in the afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...A weak and dry cool front will reach the
Monterey Bay area this evening and stall overnight and Saturday
morning. Low clouds /MVFR/ will continue to fill in through the
evening, onshore winds 5 to 10 knots will gradually decrease later
tonight and become southeasterly in the Salinas Valley and along
the Monterey Peninsula. An upward flux of heat and water vapor at
the air/sea interface over the Monterey Bay are favorable for
additional low cloud development including possibly lowering
ceilings to IFR tonight and Saturday morning. Smoke and haze from
the Moss Landing hazardous fire will be in the mix and tend to
lower surface and slant range visibility as well tonight and
Saturday. Southeasterly wind eventually lifts low cloud ceilings
Saturday either by later morning or early afternoon. Surface to
lower level winds will shift to easterly to northeasterly during
the day.

&&

.MARINE...
(Tonight through next Thursday)
Issued at 847 PM PST Fri Jan 17 2025

Surface high pressure will build over the Great Basin tonight and
Saturday, weaken Sunday, then restrengthen Sunday night through
the middle of next week. Winds will be mainly light during the
forecast period. A long period westerly swell will develop by
Saturday evening and continue to Sunday, easing to a moderate
period westerly swell by early next week.

&&

.BEACHES...
Issued at 847 PM PST Fri Jan 17 2025

A long period westerly swell develops by Saturday evening and
continues to Sunday, easing to a moderate period westerly swell
Sunday night and Monday. Initial swell periods near 20 seconds
Saturday evening will result in an increasing risk of forerunner
and sneaker waves. The risk of sneaker waves continues Saturday
night and Sunday. Breakers upwards to 13 to 14 feet will be
possible Saturday evening to Sunday. Will soon look into possibly
needing a beach hazards statement, please stay tuned to updates.

Sneaker waves can sweep across the beach without warning, pulling
people into the sea from rocks, jetties, and beaches. Sudden
immersion in cold water can result in cold water shock even for
the most experienced swimmers. Cold water shock can result in
dramatic changes in breathing, heart rate and blood pressure,
greatly increasing the risk of drowning in rough open waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory from 1 AM to 9 AM PST Saturday for CAZ516>518.

PZ...None.
&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Canepa
MARINE...Canepa

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