Technical NOAA Weather Discussion

FXUS66 KMTR 020049
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
449 PM PST Thu Jan 1 2026

...New MARINE...

.KEY MESSAGES...
Updated at 145 PM PST Thu Jan 1 2026

 - High astronomical tides combined with storm surge will bring 
   minor to moderate coastal flooding around high tide through 
   Sunday

 - Strong southerly winds expected Friday night into Saturday

 - Slight chance of thunderstorms Friday night through the weekend

 - Daily rain likely through early next week 

&&

.SHORT TERM...
Issued at 145 PM PST Thu Jan 1 2026
(This evening through Friday)

Rain showers with the potential for isolated thunderstorms will 
continue through this afternoon as the atmosphere becomes more 
unstable as peaks of sun are starting to make an appearance. Thus, 
heating will result in up to 250-500 J/kg of surface based CAPE. 
Convection is starting to pop up across the Central Coast and in the 
Santa Cruz Mountains, so this afternoon could be get a bit 
interesting. Any heavier showers and thunderstorms that do develop 
will be capable of producing small hail, gusty erratic winds, and 
possible funnel clouds. 

As we head into tonight and early Friday morning, conditions appear 
to dry out a bit as a weak shortwave ridge builds into the region. 
This will be short lived before an atmospheric river moves through 
Friday night into Saturday. 

&&

.LONG TERM...
Issued at 145 PM PST Thu Jan 1 2026
(Friday night through next Wednesday)

A strong fold front will approach the coast with strong southerly 
winds developing Friday afternoon with the strongest anticipated to 
be ahead of and along the frontal boundary. These stronger winds will 
advect deeper moisture with PWAT values between 1.00-1.25" across 
the entire Bay Area and Central Coast through Saturday morning. 
Additionally, strong showers or thunderstorms will also be likely 
through Saturday morning as a result of the stronger winds and 
lifting mechanism of the frontal passage. Wind gusts are forecast to 
reach between 40-50 mph along the coast and in the higher terrain. 
Thus, a Wind Advisory remains in effect for the aforementioned 
areas from 1 PM Friday through 1 PM Saturday. While these winds will 
not be strong as last week, downed trees/limbs may result in 
isolated to scattered power outages. 

In wake of the frontal passage, 500 mb temperatures will drop to 
around -16C to -24C allowing for steepening lapse rates that may 
support deeper convection on Saturday. Another reinforcing front is 
forecast to arrive Sunday morning and into the afternoon and then 
again on Monday, which will bring additional rounds of moderate to 
heavy rain. However, southerly winds aren't expected to be as strong 
and those Friday night into Saturday. There is still a bit of 
uncertainty in the ensemble guidance for the rest of next week, 
however conditions look to remain cool and unsettled. 

&&

.AVIATION...
(00Z TAFS)
Issued at 405 PM PST Thu Jan 1 2026

An unsettled pattern continues to provide a mix of mostly VFR and
MVFR cigs. We're entering a bit of a lull in widespread rainfall,
but scattered on-and-off showers persist overnight through mid- 
morning Friday when a strengthening storm system begins moving 
onshore Friday afternoon. Expect strong southerly winds impacting
all terminals by Friday afternoon and persisting through the 
remainder of the TAF period with light to moderate rain and a
slight chance of thunderstorms.

Vicinity of SFO...VFR is expected to persist through the forecast
period with a slight chance of MVFR cigs when showers are in
vicinity of the terminal. Strong southerly winds may pick up as
early as late morning Friday morning out ahead of the advancing
frontal boundary. Strong winds will then persist through the
remainder of the forecast period with light to moderate showers 
and a slight chance for thunderstorms.

SFO Bridge Approach...Similar as SFO.

Monterey Bay Terminals...VFR cigs are expected until early 
evening with low confidence in MVFR ceilings that may hover 
between the two categories. The advancing frontal boundary will 
be felt more to the north with lesser impacts for KSNS and KMRY. 
However, strong southeasterlies will increase through the Salinas 
Valley overnight and remain strong through the remainder of the 
TAF period.

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 449 PM PST Thu Jan 1 2026

Small Craft Advisories are in effect through the overnight,
however may be borderline at times especially for the western
portion of our southern outer waters. After sunrise Friday, gale
force winds quickly spread over our inner and outer waters as a
strong storm system moves on shore over the course of the day.
Along with the strong wind, expect light to moderate showers at
times with a slight chance of thunderstorms and rough seas. Rain
chances and breezy winds continue into next week.

&&

.BEACHES...
Issued at 900 AM PST Thu Jan 1 2026

Perigean spring tides (King Tides) will impact the region through
Sunday. This is due to the combination of the full moon on 1/3, 
lunar perigee on 1/1, and perihelion on 1/3. In other words all 
three planetary bodies are lined up and close to each other. In 
addition to the high astronomical tide, the incoming low pressure 
system will bring strong southerly winds, generating some storm 
surge. The combination of these factors will bring minor to 
moderate coastal flooding to the low-lying areas near shorelines 
and tidal waterways during high tide through Sunday. At the San 
Francisco tidal gauge, high tide is expected to be 2.2 ft above 
normal at 9:34 AM Friday, 2.5 ft above normal at 10:26 AM 
Saturday, and 1.8 ft above normal at 11:18 AM Sunday. These 
predictions include up to 1.3 feet of storm surge that will 
enhance the astronomical tide and flooding threat. High tide 
varies up to 90 minutes earlier or later along the Pacific Coast 
and through the San Francisco Bay, respectively.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 2 PM PST Sunday for CAZ006-505-506-
     508-509-529-530.

     Wind Advisory from 1 PM Friday to 1 PM PST Saturday for CAZ006-
     502>505-509-512-515>518-528>530.

PZ...Small Craft Advisory from 3 PM Friday to 3 AM PST Saturday for 
     SF Bay N of Bay Bridge.

     Small Craft Advisory until 9 PM PST Friday for Mry Bay.

     Gale Warning from 9 PM Friday to 3 AM PST Saturday for Mry Bay.

     Small Craft Advisory until 9 AM PST Friday for 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 Reyes to Pigeon Pt 0-10 nm.

     Gale Warning from 9 AM Friday to 3 AM PST Saturday for 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 Reyes to Pigeon Pt 0-10 nm.

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

     Gale Warning from 3 AM Friday to 3 AM PST Saturday for Pt Arena 
     to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...JM
MARINE...JM

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Prepared by Boulder-Creek.com Weather at: Thu Jan 1 18:30:02 PST 2026
From the National Weather Service