FXUS66 KMTR 251744
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
944 AM PST Thu Dec 25 2025
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1052 PM PST Wed Dec 24 2025
- Strong and damaging winds continue overnight through Thursday
evening.
- A flood watch remains in effect through Friday evening across
the region. The main threat is flash flooding and landslides
from high rain rates.
- Slight chances for severe thunderstorms begin this evening and
continue through Thursday evening. Severe threats include
damaging wind gusts and possible tornadoes.
- Dangerous beach and marine conditions continue through Friday
across the Pacific coast and adjacent beaches.
- Cold temperatures settle in this weekend after the storms break
&&
.UPDATE...
Issued at 532 AM PST Thu Dec 25 2025
The main rain band has passed to the east of us. Severe
Thunderstorm Warnings and Flash Flood Warnings were issued
overnight across the Bay Area as the damaging winds and intense
rain came through the region. Wind gusts remain elevated across
the region, and the immense rainfall is still making its way
across the urban landscape of the Bay Area. We are continuing to
receive reports of roadway flooding across the Bay Area. If you
come across a flooded roadway, turn around, don't drown! Even if
you don't, take care if you do have to travel across the region
today, as the intense winds brought down trees, branches, and
power lines across the roadways.
Scattered showers continue through the morning with the latest
high resolution guidance showing a signal for some organized
thunderstorms to return late this afternoon and this evening as a
shortwave approaches the state.
Highest wind reports overnight are 92 mph at the North Peak
Access Road PG&E station in northwestern San Mateo County, 91 mph
at the O'Neill Sea Odyssey station near Santa Cruz harbor, and 90
mph at the Mount Umunhum PG&E station and the Gunsight Fire Road
PG&E station in the Marin County highlands. Downtown San Francisco
reported 0.74 inches of rain from 5 PM yesterday to 5 AM this
morning.
DialH
&&
.SHORT TERM...
Issued at 1052 PM PST Wed Dec 24 2025
(Tonight through Friday)
Don't let your guard down, the line of showers and thunderstorms
with strong winds that swept through our area earlier this
(Wednesday) evening was only a precursor to what is expected to
be the most impactful line of storms yet, that is currently about
to enter our outer marine zones about 100mi offshore. Impacts for
the next line are expected to be felt by Midnight PST, with
another round of strong wind, periods of heavy rain with the
potential of low top supercells producing waterspouts that could
move onshore as short-lived tornadoes or straight line winds up
to 80 MPH or higher. The High Wind Warning remains in place until
10 AM PST Thursday (Christmas) morning and may be extended. Our
Flood Watch remains in place until Friday night at 10 PM PST. The
SPC continues to have our entire Pacific Coast line in a Marginal
Risk for Severe Thunderstorms through early Friday morning at 4
AM. That means, the line off showers and thunderstorms progged to
move onshore as early as late afternoon Thursday into the evening
hours may be just as impactful as the one currently on our door
step. That means all hazards mentioned above are in play through
at least tomorrow night, along with the dangerous beach hazards
and gale to near storm force winds over both our coastal and outer
waters. If traveling Christmas day or night, expect extensive
travel delays, along with power outages and urban/nuisance
flooding.
&&
.LONG TERM...
Issued at 1052 PM PST Wed Dec 24 2025
(Friday night through next Wednesday)
*Long term discussion remains unchanged from Wednesday afternoon
update*
Starting in the early morning Friday, winds and shower activity
will gradually decrease as the low pressure system offshore opens
up into a trough and moves into northern Oregon. The associated
surface trough axis will move across the Bay Area Friday evening.
This will finally flip the winds back to northerly, bringing
drier, cooler weather for the weekend. The 1000-500 mb thickness
actually increases this weekend, with the cooling coming mainly from
enhanced radiation during in the cloudless nights. Sunday through
Tuesday look particularly calm, clear and cool as a 500 mb ridge
sets in. The next troughing pattern looks probable on the 1st or
2nd, just in time for King Tides. There's no strong signal for
major impacts yet, but the CW3E ECCC AR Activity tool shows higher
than normal chances for atmospheric rivers through the first half
of January.
&&
.AVIATION...
(18Z TAFS)
Issued at 929 AM PST Thu Dec 25 2025
A dry slot is allowing some sun to reach the ground, but strong
southerly winds are ongoing. Showers and thunderstorm activity
will increase through the afternoon, with a distinct peak in
activity expected around 01-03Z as a line of strong thunderstorms
rolls through. Behind this line, the activity will switch to more
scattered showers and moderate to strong southerly winds for the
remainder of the TAF period.
Vicinity of SFO...Winds will stay fixed from the south all day.
There is some uncertainty regarding the onset of rain showers and
possible thunderstorms. The latest high resolution guidance shows
a line of showers developing around 19-20Z, but it's unclear if
these storms will train over SFO or stay further south. The final
push of strong showers and likely thunderstorms should move
through around 01-02Z and I've included a TEMPO line in the TAF
for these brief, but impactful conditions. After this main band
moves through, showers will become lighter and much more
scattered, but the strong southerly winds will remain through the
TAF period and into Friday before finally shifting back to
westerly and easing Friday night.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...The southern terminals have the
best chance of dodging the initial push of shower activity this
afternoon, but will still be hit by the stronger band that rolls
through this evening. Winds will remain strong out of the south
all day and into Friday.
&&
.MARINE...
(Today through Tuesday)
Issued at 929 AM PST Thu Dec 25 2025
...HAZARDOUS MARINE CONDITIONS CONTINUE INTO EARLY FRIDAY...
While the Storm Warnings have ended, Southeast gales continue
across the coastal waters and will persist into Friday morning.
These dangerous winds are accompanied by a chance for
thunderstorms and possible waterspouts through the evening. Very
rough, choppy seas will accompany these gales and linger through
the day Friday, reinforced by a moderate westerly swell. If your
vessel is not able to handle these conditions return to port or
seek protected waters as soon as possible.
&&
.BEACHES...
Issued at 325 PM PST Wed Dec 24 2025
A Beach Hazards Statement has been issued for the coast through
4AM Friday. The main concerns include:blowing and drifting sand
and wind waves up to 20 ft. The drifting sand and increased sea
spray will also result in poor visibilities, affecting water
rescues. Increased coastal erosion will be possible as well.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through late tonight for CAZ006-505-509-
529-530.
Flood Watch through Friday evening for CAZ006-502>506-508>510-
512>518-528>530.
High Wind Warning until 10 AM PST this morning for CAZ006-503-
505-509-517-528>530.
Wind Advisory until 10 AM PST this morning for CAZ502-504-506-
508-510-512>516-518.
PZ...Gale Warning until 3 AM PST Friday for Mry Bay-Pigeon Pt to Pt
Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 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-SF
Bay N of Bay Bridge.
&&
$$
SHORT TERM...JM
LONG TERM....JM
AVIATION...Flynn
MARINE...Flynn
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Prepared by Boulder-Creek.com Weather at: Thu Dec 25 10:30:02 PST 2025
From the National Weather Service
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