FXUS66 KMTR 100652
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1152 PM PDT Fri Oct 9 2026
...New SHORT TERM, LONG TERM...
.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...
(06Z TAFS)
Issued at 929 PM PDT Fri Oct 9 2026
The first half of the TAFs is focused on IFR-MVFR stratus
developing and clearing. The second half of the TAFs is dealing
with strong onshore winds. Currently STS, APC, HAF, MRY and SNS
have IFR-MVFR ceilings, SFO and OAK may develop them for a few
hours, and SJC and LVK are probably safe. A dry cold front coming
from the north will bring drier air and strong onshore winds
through the day Saturday.
Vicinity of SFO...While there is still a chance for ceilings
overnight, the current satellite loop shows a pretty good hole
over the terminal that hasn't been shrinking at all. OAK has a
better chance of ceilings. The forecast is far from certain,
however, as the SW winds will shift to a more westerly direction
as the front approaches tonight. That, combined with the deepening
marine layer, brings a chance for stratus to reach the terminal
through the San Bruno Gap. On the other hand, the air behind the
cold front is more dry, and the stronger winds should help mix out
the lingering low-level moisture. Winds will increase through the
day Saturday, with gusts up to 30 kts expected in the afternoon
and early evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...MVFR ceilings are likely to persist
through the night before clearing sometime around 18Z. The winds
won't be as strong as the SF Bay Area.
&&
.MARINE...
(Tonight through next Thursday)
Issued at 929 PM PDT Fri Oct 9 2026
Conditions are dangerous across the coastal waters this weekend.
Strong NW winds have arrived in the northwestern outer waters and
will spread south through the night as a cold front moves through.
Frequent gale force gusts are expected in exposed waters. Rough
to very rough seas will build in response to the strong winds. On
top of the hazardous winds and rough wind waves, 2 sets of swell
arrive this weekend, from both the south and west. The significant
wave height will reach 15 feet in the 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 from 7 AM PDT Saturday 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 Saturday to 9 AM PDT Sunday for
Mry Bay.
Gale Warning until 9 PM PDT Saturday for Pt Arena to Pt Reyes 0-
10 nm.
Small Craft Advisory from 3 AM Saturday to 9 AM PDT Sunday for
Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory from 9 AM Saturday 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...Flynn
MARINE...Flynn
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Prepared by Boulder-Creek.com Weather at: Sat Oct 10 02:30:04 PDT 2026
From the National Weather Service
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