FXUS66 KMTR 101125
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
425 AM PDT Sat Oct 10 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 927 PM PDT Thu Oct 8 2026
- Sharp cool-down this weekend and early next week
- Coastal flooding during high tides through mid-week
- Beach Hazards Saturday morning until Monday evening
- Light rain possible north Central Coast early next week
&&
.SHORT TERM...
Issued at 1152 PM PDT Fri Oct 9 2026
(Tonight through Sunday)
Much cooler air quickly flowed inland Friday with about equally
weighted northerly ACV-SFO and onshore SFO-SAC pressure gradients
supporting northwest winds. Current 24 hour temperature trends
remain sharply lower by up to double digits Fahrenheit across
higher elevations and inland. Surface temperatures across the
highly varied terrain in our forecast area show only a few places
left at highest elevation that are still relatively mild from the
mid 60s to lower 70s. Due to a pattern shift with upper level
troughing forecast to dominate our weather through the weekend,
the lower level temperature inversion is already steadily weakening
and lifting. The marine layer depth continues to increase, currently
between ~ 1700 and 2500 feet. Cooling applied to the marine layer
with upsloping winds will produce light patchy drizzle from San
Francisco southward to the Big Sur coastline, including the East
Bay hills tonight and Saturday morning.
Cold air advection continues through Saturday greatly weakening
the lower level temperature inversion that's capping the marine
stratus. Expect plentiful vertical mixing with drier air and
daytime surface heating to mix out the stratus by early afternoon.
Highs and lows Saturday and Sunday will be below to much below
normal for the time of year. Highs in the 60s/70s, warmest inland.
Lows in the 40s/30s, coldest far inland valleys, except near 50
along the immediate coastline and bays.
&&
.LONG TERM...
Issued at 1152 PM PDT Fri Oct 9 2026
(Sunday night through next Friday)
500 mb troughing will prevail with mainly drier air flowing
southward across our forecast area early to mid next week. There
may be a little light measurable shower activity in the southernmost
forecast area later Sunday and Monday. However, recent NBM has
trended drier to less than 0.10" liquid precipitation. 500 mb
ridging will advance eastward over our forecast area mid to late
next week, bringing a return to warmer daytime temperatures.
&&
.AVIATION...
(12Z TAFS)
Issued at 412 AM PDT Sat Oct 10 2026
Primarily a mix of MVFR and VFR with a marine layer at ~2500ft
from the 12z KOAK balloon. Drier air associated with a cold front
currently pushing south through our area can be seen gradually
eroding stratus both onshore and offshore early this Saturday
morning. Current condition's should only improve from this point
until clearing leads to VFR by mid-morning for the North Bay and
Bay Area terminals, late morning for Monterey Bay sites.
Vicinity of SFO...VFR conditions are expected through the TAF
period however MVFR cigs will persist in vicinity of terminals
through mid-morning with gusty winds this afternoon and tonight in
the wake of the cold front pushing through our area currently.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...MVFR ceilings will persist until late
morning with VFR expected throughout the remainder of the TAF
period. Breezy onshore flow will develop behind the advancing cold
front later today and tonight.
&&
.MARINE...
(Today through Thursday)
Issued at 412 AM PDT Sat Oct 10 2026
Dangerous conditions remain in place across our coastal waters
this weekend. Strong northwest winds have begun to spread south
as a cold front moves through. Expect frequent gale force gusts
in exposed waters along with rough to very rough seas building in
response to the strong winds. On top of the hazardous winds and
rough wind waves, two sets of swell haver arrived, from both the
south and west. The significant wave height will reach 16 feet in
the northern outer waters.
&&
.BEACHES...
Issued at 446 AM PDT Fri Oct 9 2026
Hazardous beach conditions will be present at Pacific Coast beaches
Saturday through Monday. Long period southerly swell from distant
Tropical Storm Rachel will build in height through the weekend,
bringing an increased risk of sneaker waves and strong rip currents.
Long period westerly swell from a gale force low in the Central
North Pacific will arrive Sunday, bringing breaking waves up to 16
feet. The large tidal swings will also result in coastal erosion as
water and waves are brought farther up the beach than normal,
especially during high tide. Remain off jetties, piers, rocks, and
other waterside infrastructure as waves can sweep across the
shoreline without warning, pulling people into the sea. Remain out
of the water to avoid hazardous surf and strong rip currents and
never turn your back on the ocean!
Sarment
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 3 PM PDT Tuesday for CAZ006-508-529-
530.
Beach Hazards Statement through Monday evening for CAZ006-505-
509-529-530.
Coastal Flood Advisory until 4 PM PDT Wednesday for CAZ506.
PZ...Small Craft Advisory until 3 PM PDT Sunday for Pigeon Pt to Pt
Pinos 10-60 NM-SF Bay N of Bay Bridge.
Small Craft Advisory from 9 AM this morning to 9 AM PDT Sunday
for Mry Bay.
Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
Reyes 0-10 nm.
Small Craft Advisory until 9 AM PDT Sunday for Pt Reyes to
Pigeon Pt 0-10 nm.
Small Craft Advisory from 9 AM this morning to 3 PM PDT Sunday
for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras
Blancas 0-10 nm.
Gale Warning until 9 AM PDT Sunday for Pt Arena to Pt Reyes 10-
60 NM.
&&
$$
SHORT TERM...Canepa
LONG TERM....Canepa
AVIATION...JM
MARINE...JM
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Prepared by Boulder-Creek.com Weather at: Sat Oct 10 06:30:04 PDT 2026
From the National Weather Service
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