Yountville, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

320
FXUS66 KMTR 220557
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
957 PM PST Sun Dec 21 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 344 PM PST Sun Dec 21 2025

 - Flood Watch remains in effect through Monday afternoon for the
   North Bay; extension in time and coverage likely

 - Moderate to heavy rain overnight into early Monday across the
   North Bay may lead to minor flooding over roadways overnight
   into Monday morning, turn around don`t drown!

 - Chances for moderate to heavy rain increase for interior
   locations south of the North Bay late Tuesday through early
   Friday, with increasing chances for urban flooding and
   extensive travel delays

 - Impactful and likely very hazardous winds Tuesday through early
   Friday along our entire coastline and higher elevations inland

 - Dangerous beach conditions likely late Tuesday through Friday
   for all Pacific Coast beaches

&&

.SHORT TERM...
Issued at 344 PM PST Sun Dec 21 2025
(This evening through Monday)

Steady rain, moderate to heavy at times, from the ongoing
atmospheric river will continue over the North Bay for the remainder
of today and through the overnight into early Monday morning. The
moisture plume oscillates back to the south, primarily over the Bay
Area during the day Monday, with both GFS/ECM IVT values backing
off, ranging from 0-250kg/m/s through the day tomorrow.

The most recent forecast for the Mark West Creek near Mirabel
Heights approaches action stage around sunrise Monday morning where
it will level off for the remainder of the day when the rainfall
shifts south. Despite the temporary weakening of the atmospheric
river, periods of moderate/heavy rain in the Santa Cruz mountains
will produce 2-3" from late tonight through Monday evening with
lesser amounts expected for the southern Marin coastal ranges and
the Santa Lucia, ~1-2" due to a nearly saturated boundary layer near
and along the coast.

Although much of the area is expected to see some rain Monday, it
will be mostly light and on-and-off away from the coastal ranges,
with little impact. Might be a good day to make final preparations
for the upcoming holiday. Beginning Tuesday, first along the
coastline in the morning, then later inland - the wind and the rain
ramp back up considerably.

&&

.LONG TERM...
Issued at 344 PM PST Sun Dec 21 2025
(Monday night through next Saturday)

Confidence is high for the strong winds to begin to develop along
our Pacific Coast line Tuesday afternoon into Wednesday morning. A
series of disturbances rounding the base of a trough associated with
a deepening closed low well to the north will produce 925mb flow
over 50kts at times below 80-90kt 500mb flow. By early Wednesday
morning, southerly winds along our coast from Big Sur up to Point
Reyes may reach 70-80mph at times. It will be very dangerous to
spend anytime near our beaches or to be in our coastal waters
Tuesday through Friday. The first wave will push a strong cold front
through our entire area early Wednesday morning with periods of
heavy rain and a slight chance of thunderstorms that could produce
strong wind gusts up to 70mph or higher along with brief downpours.
The North Bay and coastal ranges have been benefiting the most from
rainfall from the atmospheric river out ahead of the powerful upper
level low. Its Wednesday through Thursday when much of our interior
will see its highest rainfall totals. A High Wind Watch watch is
likely to be hoisted over the next 24hrs along our coastal areas,
and at least a Wind Advisory for large portions of our interior
Wednesday and Thursday (Christmas Day) when gusts may reach 40mph in
low-lying areas, and 60mph or higher along inland peaks. A second,
maybe slightly less dynamic front pushes through our area Christmas
Day through Christmas night, with similar impacts, periods of heavy
rain and strong winds. Winds begin to ease and a drier airmass
appears to set in over the course of the day Friday into next
weekend.

Remember, this is still 4-5 days out, the forecast details and
timing can and will change as we move through the holiday period.
Confidence is high that both Christmas Eve and Christmas Day will
see our entire area experience periods of moderate/heavy rain with
strong winds. Keep checking back as the forecast is refined over the
coming days for improved timing of the worst impacts.

&&

.AVIATION...
(06Z TAFS)
Issued at 935 PM PST Sun Dec 21 2025

Rainfall expected to intensify across the Bay Area overnight and
through Monday morning with gusty southerly winds continuing into
late morning. Moderate confidence in winds turning more
northwesterly behind the cold front, but the cold front is
expected to stall along the Bay Area and gradually drift back
northwards by Monday night. This will result in winds shifting
back to southerly through the overnight hours Monday night.

Vicinity of SFO...Current radar showing rainfall offshore of the
SF Peninsula which is anticipated to impact the terminal through
the overnight hours tonight. Southerly winds will continue through
tonight and will likely become very light or even turn
northwesterly by Monday afternoon as the cold front sags south of
the terminal. This trend will reverse through Monday night as the
front gradually lift back to the north and winds become southerly
again.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Mostly dry through this TAF period with
very scattered showers during the Monday morning hours, which
will likely clear out through midday as the cold front moves back
to the north through Monday afternoon.

&&

.MARINE...
(Tonight through next Saturday)
Issued at 935 PM PST Sun Dec 21 2025

Showers continue across the waters north of Point Pinos tonight
and through Monday. Winds subside slightly Monday as the front
lift back to the north. A significant change takes place Tuesday
as a near-storm-force surface low traverses the waters from the
southwest towards the Northern California coast. This surface low
will undergo rapid intensification as it approaches the coast
Tuesday night. There is a chance for isolated thunderstorms across
the waters through Wednesday before another strong surface low
enters the waters late Wednesday night. Seas build through the
week and will be very hazardous to mariners with the potential for
wave heights in excess of 20 feet.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Watch late Tuesday night for CAZ006-502>506-508>510-
     512>518-528>530.

     Flood Watch through Monday afternoon for CAZ502>506.

PZ...Gale Warning from 9 PM Tuesday to 3 AM PST Wednesday for SF Bay
     N of Bay Bridge.

     Gale Warning from 9 AM Tuesday to 3 AM PST Wednesday for Mry Bay-
     Pigeon Pt to Pt Pinos 10-60 NM.

     Gale Warning from 9 AM to 3 PM PST Tuesday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt
     Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Storm Watch from Tuesday afternoon through late Tuesday night
     for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10
     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 Monday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Gale Warning from 3 PM Tuesday to 3 AM PST Wednesday for Pt
     Arena to Pt Reyes 10-60 NM.

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

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...Behringer
MARINE...Behringer

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