FXUS66 KMTR 262049
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1249 PM PST Fri Dec 26 2025

...New SHORT TERM, LONG TERM...

.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...
(18Z TAFS)
Issued at 951 AM PST Fri Dec 26 2025

Today is a transition from southerly flow and stormy conditions to
dry northerly flow. Before we get to that, there is one last round
of organized showers that will move through from late morning
through the afternoon. Showers are expected for a couple hours at
all terminals before the line pushes through and shower activity
becomes much more isolated through the evening and overnight
hours. Winds will finally shift back to the standard NW direction
overnight with much more favorable aviation weather conditions to
follow.

Vicinity of SFO...The latest high resolution guidance shows the
last line of organized showers will arrive around 22-23Z and clear
by 00-01Z. Winds should finally shift back to westerly shortly
after when the trough axis moves through. Winds will continue to
gradually shift to NW overnight.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...A few isolated showers are expected
through the late morning before the more organized band arrives
around 00-03Z. Winds won't be as strong at the southern terminals
since the parent low pressure system is far to the north.

&&

.MARINE...
(Today through Wednesday)
Issued at 951 AM PST Fri Dec 26 2025

Strong SW winds will gradually decrease through the day and shift
to northerly overnight. A line of showers and possible
thunderstorms is expected this afternoon. Wind speeds will
continue to diminish through the weekend. The seas are very rough
today from a combination of westerly swell and southerly wind
waves. Small craft advisories remain in effect until Saturday as
the swell gradually subsides below 10 feet by Sunday. Much quieter
marine conditions are expected next week.

&&

.BEACHES...
Issued at 638 AM PST Fri Dec 26 2025

A High Surf Advisory is then valid for the coast through 10 PM 
Friday. 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 3 PM PST this afternoon for Mry Bay-
     SF Bay N of Bay Bridge.

     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...Flynn
MARINE...Flynn

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Prepared by Boulder-Creek.com Weather at: Fri Dec 26 14:30:03 PST 2025