FXUS66 KMTR 271200
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
400 AM PST Sat Dec 27 2025

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

.KEY MESSAGES...
Updated at 359 AM PST Sat Dec 27 2025

 - High pressure builds in with dry weather on through early to mid 
   next week.

 - Cold overnight lows through early next week.&&

.SHORT TERM...
Issued at 359 AM PST Sat Dec 27 2025
(Today and tonight)

Upper level ridging builds to our east, pushing the upper level 
trough off to our west. THis will usher in drier weather to the 
region with most lingering showers being cut off by morning. Cooler 
weather is on tap with high temperatures chilling in the low to mid 
50s for many valley and coastal communities, while mountainous 
regions vary from the low 40s to the mid 50s. Tonight, temperatures 
are expected to be cold as well. The question will be, do we get 
some high clouds skirting across the Bay Area counties? Should that 
happen temperatures might be a few degrees warmer than forecast. 
Should it not happen, we could be a few degrees colder due to 
radiational cooling. That would fall more inline with the some of 
the MOS guidance. Farther to the south, mostly clear skies should 
prevail with temperatures for the interior Central Coast falling 
into the 30s, perhaps lower for some of the higher elevation areas. 
A Cold Weather Advisory has been hoisted these areas. 

&&

.LONG TERM...
Issued at 359 AM PST Sat Dec 27 2025
(Sunday through Friday)

Ensemble guidance favors upper level ridging through Tuesday into 
Wednesday, with some uncertainty setting up for the end of the week. 
Models show that the upper trough gets  elongated, cut off, and then 
shoved to the southwest over the Pacific. It then meanders there for 
quite some time while ridging nestles over us. By mid week guidance 
shows upper level troughing from the Gulf of Alaska trying to dig 
southwards pushing ridging to the east. It is here, where the models 
begin to show variance between upper level troughing and quasi 
zonal flow for the latter half of the work week. The NBM paints POP 
over us starting as early as early as late Wednesday into Thursday, 
with rain chances lingering through Friday. Rain at this point looks 
to be beneficial. It will be worth watching to see if the Gulf 
trough is able to breakdown the ridge and allow for the wetter 
weather pattern or if the ridge is a bit more resilient. Stay tuned 
to the forecast. 

&&

.AVIATION...
(12Z TAFS)
Issued at 341 AM PST Sat Dec 27 2025

Some very light, brief showers remain over the region this
morning, but will be exiting the area by sunrise. Patchy MVFR
stratus this morning associated with linger clouds from this
week's storm system and localized FG around KSTS will all clear to
VFR by around sunrise today, then VFR persists through the rest of
the TAF period. High confidence in mostly clear skies going into
tonight and Sunday morning.

Vicinity of SFO...Largely unproblematic forecast with skies 
clearing to VFR this morning and lasting through the TAF period (high
confidence). One hitch may be a slight shift in the winds with a
weak easterly component overnight tonight in the pre-dawn hours
Sunday morning. So slight chance of NE/SE winds during this
period, but speeds expected to remain below 6-7 kts.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Lingering showers this morning (light
and brief), then clearing out to VFR by around sunrise. VFR
through the rest of the period with generally light onshore winds
during the afternoons (high confidence).

&&

.MARINE...
(Today through Thursday)
Issued at 341 AM PST Sat Dec 27 2025

Very rough seas will begin to diminish this morning due to a
combination of westerly swell and leftover 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...Cold Weather Advisory from 2 AM to 9 AM PST Sunday for 
     CAZ516>518-528.

PZ...Small Craft Advisory until 9 AM PST this morning 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 this afternoon for Pigeon Pt 
     to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Behringer
MARINE...Behringer

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Prepared by Boulder-Creek.com Weather at: Sat Dec 27 06:30:02 PST 2025