FXUS66 KMTR 270531
AFDMTR

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

...New AVIATION...

.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

&&

.UPDATE...
Issued at 843 PM PST Fri Dec 26 2025

The last line of showers is currently pushing through Monterey and 
San Benito counties and is losing strength. Lingering light showers 
will continue to move through the region overnight, but will be 
spotty. Expect these showers to dissipate through the morning and 
end into Saturday afternoon, leading us into another period of 
quieter weather until the new year. 

&&

.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...
(06Z TAFS)
Issued at 931 PM PST Fri Dec 26 2025

Radar and satellite show a few lingering isolated showers. VFR-
MVFR tonight and Saturday with exception of patchy morning fog 
/LIFR-IFR/.

Vicinity of SFO...VFR tonight and Saturday. West-northwest wind 
near 10 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR with post frontal winds becoming 
southwest to west near 10 knots tonight and Saturday. 

&&

.MARINE...
(Tonight through next Thursday)
Issued at 843 PM PST Fri Dec 26 2025

Very rough seas will prevail through Saturday 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. High pressure and dry weather
return for the weekend and early next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 10 PM PST this evening for CAZ006-505-
     509-529-530.

     Flood Watch until 10 PM PST this evening for CAZ516>518-528-530.

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...Canepa

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