FXUS66 KMTR 271719
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
919 AM PST Sat Dec 27 2025
...New AVIATION, MARINE...
.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.
&&
.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...
(18Z TAFS)
Issued at 919 AM PST Sat Dec 27 2025
Currently a mixed bag of LIFR-VFR at the terminals. Lingering rain
showers are bringing low-end VFR to high-end MVFR conditions to the
southern terminals. After these exit to the south and dense fog in
the North Bay mixes out, VFR conditions will prevail through the
day. Dense fog is expected to return to APC and STS tonight. Onshore
winds will diminish and give way to drainage winds tonight.
Vicinity of SFO...High confidence in VFR through the TAF period.
Winds will generally veer through the TAF period.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Currently VFR and calm at both terminals.
Lingering rain showers may bring brief reductions to MVFR.
&&
.MARINE...
(Today through Thursday)
Issued at 919 AM PST Sat Dec 27 2025
Hazardous marine conditions will continue for the inner waters and
outer waters through this afternoon. Conditions will slowly begin
to improve tonight as strong northerly winds diminish and rough
seas abate. By tomorrow afternoon, moderate northerly breezes and
moderate seas will prevail.
&&
.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 3 PM PST this afternoon 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 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.
&&
$$
SHORT TERM...KR
LONG TERM....KR
AVIATION...Sarment
MARINE...Sarment
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Prepared by Boulder-Creek.com Weather at: Sat Dec 27 12:30:02 PST 2025
From the National Weather Service
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