FXUS66 KMTR 061144
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
344 AM PST Sat Dec 6 2025
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 250 AM PST Sat Dec 6 2025
- Persistent forecast through the next seven days with benign
conditions and no precipitation expected
- Impacts from Tule Fog in the North Bay and interior East Bay
valleys
- Next chance for rain towards the middle of the month
&&
.SHORT TERM...
Issued at 250 AM PST Sat Dec 6 2025
(Today and tonight)
Satellite imagery overnight reveals a different scenario than the
last few nights. Tule Fog remains persistent across the Central
Valley, West Delta, and far East Bay Valleys. The change is a
redevelopment of the marine layer as high pressure builds
overhead. There is stratus along portions of the coastal waters
and Bay Area with the Central Coast remaining cloud free. There
was a Cold Weather Advisory in effect for portions of the North
Bay, but an influx of low level moisture/stratus limited
widespread temps below 36 degrees. In fact, a few places saw an
increase in temperatures once the stratus developed. Therefore,
cancelled the advisory. Another interesting note are the temp
spreads across the N Bay from valley to mts with upper 30s coldest
in the valleys and low 50s highest peaks. The warmer temps are
likely being enhanced by NE winds above the stratus deck. One
weather impact that hasn't changed is patchy dense fog impacting
the N Bay and E Bay Valleys. It's patchy and not widespread enough
to warrant a dense fog advisory as of this writing.
Rest of today and tonight: clouds across the Bay Area will be slow
to clear through late morning. A cool and damp start to the day in
those locations. Outside of the stratus, temperatures are colder,
but not as cold as yesterday. Slightly warmer temps likely due to
some weak offshore flow as well. For this afternoon expect a few
clouds passing overhead as a weak front to the north washes out
against the ridge of high pressure. Given lingering stratus and
Tule fog went on colder side of guidance for Max Temps in the N
and E Bay with Upper 50s to 60s. Elsewhere, generally 60s to a
few near 70. For tonight the ridge overhead strengthens a little.
This will help to compress the marine layer. In the big picture,
not a lot of change expected in overall sensible weather with
clouds and fog impacting N and E Bay and some of the Bay Area.
&&
.LONG TERM...
Issued at 330 AM PST Sat Dec 6 2025
(Sunday through Friday)
Solid agreement with model guidance through at least Friday as
high pressure dominates CA. A gradual warming trend is expected
with peak warmth Wed-Fri as temperatures soar above normal with
interior highs reaching the upper 60s to mid 70s. The challenge
next week will be N and E Bay temps and potential Tule fog impacts
keeping temperatures colder. There continues to be a few weak
systems passing well to the north, which may lead to some drizzle
over the coastal waters but land areas remain dry.
Friday and beyond - We'll continue to monitor a lowered end chance
for a pattern change. Cluster analysis has a few clusters
breaking down the ridge. However, operational ensemble guidance
keep the ridge locked in or flattens it with zonal flow. We'll see
how this changes over the coming days.
&&
.AVIATION...
(12Z TAFS)
Issued at 337 AM PST Sat Dec 6 2025
Tule fog impacts continue this morning for North Bay and East Bay
terminals. Some fog and stratus making its way into other parts of
the Bay a bit less certain due to terrain interaction and mixing
of dry air above the marine layer. The overall pattern remains
fairly stagnant, so persistence forecast is the name of the game
through this TAF period. Anticipating another round of Tule fog
again tonight for North Bay and Bay Area terminals.
Vicinity of SFO...Patchy stratus this morning thanks to the
influence from Tule fog and light offshore wind. Some terrain-
induced mixing and weak perturbations above the marine layer will
cause some periodic clearing amongst the stratus through sunrise.
Going into tonight, reasonable to anticipate much of the same as
last night/this morning.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. Light offshore flow from Tule fog
pattern owing to drier air due to downslope off the Gabilan Range
and Santa Lucia. This pattern will very likely repeat tonight,
allowing VFR to persist through the period.
&&
.MARINE...
(Today through Thursday)
Issued at 337 AM PST Sat Dec 6 2025
Fresh northwesterly winds persist through this weekend and into
the middle of next week. Moderate seas with wave heights 6 to 8
feet across the outer waters this weekend. A new, long period
northwesterly swell is anticipated by Wednesday of next week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 3 PM PST Sunday for CAZ006-506-508-
529-530.
PZ...Small Craft Advisory from 9 AM this morning to 3 AM PST Sunday
for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 9 AM PST this morning for Pt Arena to
Pt Reyes 10-60 NM.
Small Craft Advisory until 9 AM PST Sunday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...MM
LONG TERM....MM
AVIATION...Behringer
MARINE...Behringer
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Prepared by Boulder-Creek.com Weather at: Sat Dec 6 08:30:03 PST 2025
From the National Weather Service
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