FXUS66 KMTR 110701
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1201 AM PDT Fri Sep 11 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1201 AM PDT Fri Sep 11 2026

 - Temperatures near seasonal averages through the next week

 - Breezy onshore winds this weekend

&&

.SHORT TERM...
Issued at 1201 AM PDT Fri Sep 11 2026
(Today and tonight)

What a difference a day makes. The continuing development of a 
cutoff low off the coast of British Columbia has led to a remarkable 
cooling through the evening and overnight hours, the return of a 
marine layer of around 500-1000 feet, and a stratus deck over the 
coastal regions and through the Petaluma Gap and the Golden Gate. As 
of midnight, temperatures across the Bay Area and Central Coast are 
running around 5 to 25 degrees below what they were 24 hours prior. 
Through the day, the aforementioned cutoff low will strengthen as it 
parallels the coast of the Pacific Northwest. Morning lows will 
range from the middle 50s to lower 60s in the lower elevations, and 
the middle 60s to the middle 70s in the higher elevations, while 
afternoon highs will top out in the middle 80s to the lower 90s in 
the inland valleys, the upper 90s to the triple digits in the 
warmest spots of southern Monterey County, the upper 60s to the 
lower 80s close to the Bays, and the lower to middle 60s along the 
Pacific coast. 

&&

.LONG TERM...
Issued at 1201 AM PDT Fri Sep 11 2026
(Saturday through Thursday)

The cooling trend continues into the weekend as the cutoff low moves 
into the Pacific Northwest, allowing for further development of the 
onshore flow and marine layer to take place. By the weekend, highs 
will drop into the middle 70s to middle 80s inland and the upper 60s 
to upper 70s close to the Bays. Breezy onshore winds are expected 
through the weekend as the passing cutoff low tightens the pressure 
gradient over the northern half of California. Regarding the SFO-WMC 
gradient, model output has kept the peak gradient somewhere in the 
10 to 15 mb range late on Saturday, with widespread gusts of 25 to 
35 mph possible Saturday evening into Sunday morning. Favored gaps, 
passes, and coastal regions could see gusts to 45 mph. 

The trough axis should move into the northern Rockies and the 
northern Plains for the early part of next week, but the general 
pattern should remain rather zonal for the remainder of the 7-day 
outlook, and temperatures should remain more or less stable with 
highs near or slightly below seasonal averages. 

&&

.AVIATION...
(06Z TAFS)
Issued at 935 PM PDT Thu Sep 10 2026

Shallow marine layer is hugging the coast and beginning to slowly
ooze inland. Initial impacts are mainly to HAF with IFR
conditions. IFR will prevail well into Friday for HAF with some
sct late Friday evening. Elsewhere, VFR will persist for the first
few hours tonight before stratus move farther inland dropping cigs
to MVFR/IFR, except far inland LVK/SJC/APC. VFR expected tomorrow
afternoon. Some uncertainty in the extended as the marine layer
struggle with a strengthening n to s tightening gradient. Overall
conf is moderate. Marine layer depth will likely be in the
700-1000 foot range.

Vicinity of SFO...VFR. Will bring cigs in late with some impacts
to the Friday AM rush. Clearing will be early Friday afternoon.

SFO Bridge Approach...Similar to SFO. Far S end of approach may be
more SCT than BKN/OVC Friday AM.

Monterey Bay Terminals...Eddy is forming in the bay, which may
delay initial push of stratus but expecting cigs by Friday
morning. Clearing to VFR will be mid afternoon. 

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 843 PM PDT Thu Sep 10 2026

Northerly flow will increase over the coastal waters through
Friday leading to moderate to fresh breezes. Winds will increase
further this weekend and become fresh to strong. The stronger
winds will produce locally hazardous conditions for small craft
Moderate seas will prevail through the weekend, building to
become rough in the outer waters Monday. A longer period southerly
swell will mix into the sea state due to tropical systems in the
Pacific.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Saturday for Pt Arena to Pt 
     Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 9 AM this morning to 9 PM PDT this 
     evening for Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 AM PDT Saturday for Pt Pinos to Pt 
     Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...MM
MARINE...MM

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Prepared by Boulder-Creek.com Weather at: Fri Sep 11 00:30:03 PDT 2026