Technical NOAA Weather Discussion

FXUS66 KMTR 270054
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
454 PM PST Fri Dec 26 2025

...New AVIATION, MARINE, BEACHES...

.KEY MESSAGES...
Updated at 1248 PM PST Fri Dec 26 2025

 - Slight chance for thunderstorms through this evening

 - Hazardous beach conditions will continue through tonight for
   all Pacific Coast beaches

 - Cold overnight conditions return tonight and persist into next
   week

&&

.SHORT TERM...
Issued at 1248 PM PST Fri Dec 26 2025
(This evening through Saturday)

A surface low pressure system off the Northern California Coast will 
move inland this afternoon, bringing more rain and a slight chance 
for embedded thunderstorms. Hazards will be lightning, locally heavy 
rainfall, erratic/gusty winds, and small hail. Waterspouts/tornadoes 
can't be ruled out either with the sufficient shear. The limiting 
factor of the three ingredients (lift, instability, and moisture) 
needed for thunderstorms will be moisture as PWAT has tanked to 0.56 
inches (12Z sounding) which is near the daily mean (0.52 inches) for 
this date and time. Remember: when thunder roars, go indoors! and 
see a flash, dash inside!

&&

.LONG TERM...
Issued at 1248 PM PST Fri Dec 26 2025
(Saturday night through next Thursday)

Surface high pressure over the Eastern Pacific Ocean will waste no 
time building into the Pacific Northwest behind the aforementioned 
system. As a result, dry northwesterly flow will return, restoring 
order. Calm and clear conditions will allow for radiational cooling 
and thus cold overnight conditions to return. Conditions will likely 
feel colder than what the thermometer reads due to damp conditions 
as well as the recent above normal temperatures. Global ensemble 
clusters are in agreement that an anomalously high amplitude 
longwave ridge will be over the West Coast through Tuesday, keeping 
the forecast more of the same between tomorrow and then. The pattern 
will change Wednesday when some form of troughing (either cutoff or 
open wave) gets absorbed into the longwave pattern. This will bring 
renewed chances for rainfall and maybe even thunderstorms. Soils and 
waterways will have time to relax between now and then; even so, it 
seems purely beneficial aside from a firework spectator
standpoint.

&&

.AVIATION...
(00Z TAFS)
Issued at 454 PM PST Fri Dec 26 2025

The cold front with showers and breezy to windy conditions 
continues to move eastward across the forecast area. VFR-MVFR 
tonight and Saturday with exception of patchy morning fog /LIFR-
IFR/.

Vicinity of SFO...The cold front has passed by and the wind has
shifted to westerly. VFR tonight and Saturday. West-northwest wind
10 to 15 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...The cold front will move through within
the next hour with quickly passing showers and gusty winds, the 
front continuing to move eastward away from the area tonight.
Otherwise VFR with post frontal winds becoming southwest to west
near 10 knots tonight and Saturday.

&&

.MARINE...
(Tonight through next Thursday)
Issued at 418 PM PST Fri Dec 26 2025

Strong southwesterly winds will veer to become northwesterly
behind the rain band. Embedded thunderstorms are possible through
the afternoon and into the evening with this rain band. Very rough
seas will prevail through tomorrow morning due to a combination
of westerly swell and southerly wind waves. Hazardous marine
conditions will continue through the weekend with conditions
improving by Monday.

&&

.BEACHES...
Issued at 420 PM PST Fri Dec 26 2025

A High Surf Advisory is then valid for the coast through 10 PM 
tonight. Expect large breaking waves up to 25 feet, strong rip 
currents and sneaker waves. Dangerous swimming and surfing 
conditions and localized beach erosion can be expected. Sneaker 
waves can sweep across the shoreline without warning, pulling 
people into the sea from rocks, jetties and beaches. Large 
breaking waves can overpower swimmers resulting in significant 
physical injury and increase the risk of drowning. 

Stay off of jetties, piers, rocks, and other waterside
infrastructure. Remain out of the water to avoid hazardous surf
and NEVER turn your back on the ocean. Monitor local weather,
surf and tide forecasts at www.weather.gov/mtr.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Flood Watch until 10 PM PST this evening for CAZ006-502>506-
     508>510-512>518-528>530.

     High Surf Advisory until 10 PM PST this evening for CAZ006-505-
     509-529-530.

PZ...Small Craft Advisory until 9 AM PST Saturday 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 3 AM PST Sunday for Pt Arena to Pt 
     Reyes 10-60 NM.

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

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Canepa
MARINE...Flynn

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Prepared by Boulder-Creek.com Weather at: Fri Dec 26 20:30:03 PST 2025
From the National Weather Service