FXUS66 KMTR 091736
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1036 AM PDT Fri Oct 9 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 and large swell this weekend
- Beach Hazards Saturday morning until Monday afternoon
- Light rain possible north Central Coast early next week
&&
.UPDATE...
Issued at 811 AM PDT Fri Oct 9 2026
An upper level cut-off low pressure is approximately 400 miles west-
southwest of the Monterey Bay and has allowed the marine layer to
deepen to around 750 feet in depth. As such, this resulted in less
fog this morning and further inland extent of stratus (ceilings
between 500-1000 feet). Inland areas are likely to see clearing
skies by late morning and more so into the afternoon. Meanwhile,
coastal locations have the potential to see low clouds throughout
much of the day. The aforementioned low pressure is resulting in
cooling conditions today compared to previous days! The forecast
remains on track with no updates anticipated at this time.
RGass
&&
.SHORT TERM...
Issued at 1157 PM PDT Thu Oct 8 2026
(Tonight through Saturday)
Coastal stratus will be on the increase tonight and Friday
morning. The onshore SFO-SAC pressure gradient has increased to
2.5 mb. Strong thermal ridging aloft, a compressed marine layer
combining with daily solar input resulting in well above normal
October temperatures has essentially reached its peak. Inland
daytime high temperatures will still be warm Friday, but closer
to 30 year (1991-2020) normal highs for October 9th.
Later Friday, Friday night and especially Saturday northwest winds
will result in cold air advection. A major pattern shift will usher
in strong upper level troughing i.e. much cooler air arriving here
Saturday. The marine layer lower level temperature inversion will
fully erode Saturday allowing plenty of vertical mixing. This pattern
shift will bring a noticeable cool down, especially for inland
areas.
&&
.LONG TERM...
Issued at 1157 PM PDT Thu Oct 8 2026
(Saturday night through next Thursday)
Much cooler air from the surface to aloft continues to arrive
Sunday. The strong cold core 500 mb low will sweep southward over
our coastal waters with land overlap, resulting in gusty winds
over the coastal waters and areas of gusty winds over land as
well over the weekend. There's limited moisture availability with
the low arriving from the north and a solid southerly push of
drier air and lower precipitable water values on the back side of
the low will mainly influence our forecast area over the weekend
and early next week. The depth of cold air with the low of course
will be passing over increasing sea surface temperatures as it moves
south, which may produce showers over the southern forecast area
early next week. 500 mb high pressure ridging will then move in
from the west with dry weather and an uptrend back to near mid
October normal temperatures.
&&
.AVIATION...
(18Z TAFS)
Issued at 1036 AM PDT Fri Oct 9 2026
Strong onshore flow aloft is aiding in the retention of the LIFR-
MVFR stratus deck across the region with clearing times generally
later than the previous forecast. Still expecting inland terminals
to generally clear around 18-20Z while the coastal region remains
socked in through the day. Strong onshore winds will develop through
the day with gusts up to 20 knots, with some diminishing possible
overnight as the lower layers decouple. Some LLWS concerns are
present in the interior overnight, particularly at LVK, but they are
not strong enough to mention in the TAFs. Opted to keep the
generally persistent forecast for stratus formation tonight owing to
uncertainty surrounding an approaching cold front, which may allow
stratus to dissipate or ceilings to lift. Beyond the 24-hour TAF
period, expect stronger winds to develop through Saturday.
Vicinity of SFO... VFR at the terminal through the day with a low to
moderate confidence for ceilings around 11-15Z Saturday morning,
held off on issuing a BKN line. Strong west winds will develop
through the afternoon and evening hours, with low to moderate
confidence in the wind speeds overnight as the surface winds
decouple. Strong southwest winds are possible late this evening into
the overnight hours, with the winds continuing to strengthen as they
veer to the west-northwest Saturday afternoon. Gusts above 35 kt are
not expected today or Saturday, but may need to see how the winds
develop today.
SFO Bridge Approach... Stratus remains in the corridor north of SJC
and south of the San Mateo Bridge, with moderate confidence of
dissipation around 18-19Z. Otherwise similar to SFO.
Monterey Bay Terminals... IFR stratus is expected to linger through
the day at MRY with a brief scattering in the afternoon at best, and
may clear out at SNS within the next couple of hours. Stratus is
expected to return this evening with LIFR conditions possible
overnight. A moderate onshore breeze is expected this afternoon and
late Saturday morning, persisting after the end of the TAF period.
Any influences from the incoming cold front will come after the TAF
period ends.
&&
.MARINE...
(Today through Wednesday)
Issued at 1036 AM PDT Fri Oct 9 2026
Strong northerly breezes will continue to spread into the
northern waters today with frequent gale force gusts expected by
tonight. Widespread hazardous conditions are expected by Saturday
morning through at least Sunday morning as strong to near gale
northwesterly breezes spread across the waters and build rough to
very rough seas. Long period southerly swell arriving today will
collide with long period northwesterly swell Sunday, creating a
confused sea state. Conditions will improve by Monday night as
northerly breezes diminish to become gentle to moderate and seas
subside to become moderate.
&&
.FIRE WEATHER...
Issued at 446 AM PDT Fri Oct 9 2026
Stronger onshore winds will lead to elevated fire weather conditions
across the interior and higher terrain Friday. Cooling and
moistening trend kicks off Friday with the help of a deeper marine
layer and an increase in onshore flow. Moderate to excellent
recovery is expected Friday night. Cooler, windier, and more humid
conditions are expected over the weekend with light rain possible
early next week.
Sarment
&&
.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 Saturday morning through Monday
afternoon for CAZ006-505-509-529-530.
Coastal Flood Advisory until 4 PM PDT Wednesday for CAZ506.
PZ...Small Craft Advisory until 9 AM PDT Sunday for SF Bay N of Bay
Bridge.
Small Craft Advisory from 9 AM Saturday to 9 AM PDT Sunday for
Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
evening for Pt Arena to Pt Reyes 0-10 nm.
Gale Warning from 9 PM this evening to 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 until 3 PM PDT this afternoon for Pt Arena
to Pt Reyes 10-60 NM.
Gale Warning from 3 PM this afternoon to 9 AM PDT Sunday for Pt
Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 PM this evening to 9 AM PDT Sunday
for Pigeon Pt to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...Canepa
LONG TERM....Canepa
AVIATION...DialH
MARINE...KR
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea
Prepared by Boulder-Creek.com Weather at: Fri Oct 9 12:30:04 PDT 2026
From the National Weather Service
|