FXUS66 KMTR 091513
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
813 AM PDT Fri Oct 9 2026

...New UPDATE...

.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...
(12Z TAFS)
Issued at 446 AM PDT Fri Oct 9 2026

Currently LIFR-VFR with LIFR-IFR stratus continuing to expand to 
bayshore terminals. With the exception of the coastal terminals of 
HAF, MRY, and SNS, high confidence in VFR this afternoon. Onshore 
winds will increase through the day and remain elevated overnight. 
An optimistic persistence forecast is on tap tonight. Reasonable 
best case scenario is an incoming cold front lifts ceilings or 
mixes them out completely.

Vicinity of SFO...Currently VFR with westerly flow. Moderate 
confidence in VFR prevailing through the TAF period. Stratus is 
surrounding the terminal from the north, but the compressed marine 
layer will likely be able to prevent it from penetrating the San 
Bruno Gap. Stratus will likely remain through the Golden Gate Gap 
even after it retreats around 18Z this morning. Westerly winds will 
increase through the morning and become gusty this afternoon. Winds 
will back to become southwesterly this evening before returning to 
westerly mid-morning tomorrow. Greater probability for stratus 
return tonight, but still only moderate at best. While the marine 
layer will deepen, stronger than normal winds and a dry cold 
front should help preclude stratus development.

SFO Bridge Approach...A patch of IFR stratus is developing over NUQ, 
it'll likely continue to expand to the northwest towards SFO and 
to the southeast towards SJC. Conditions will begin to improve by 
16Z with VFR expected by 19Z.

Monterey Bay Terminals...Currently LIFR with southwesterly flow at 
MRY and LIFR with westerly flow at SNS. Moderate to high confidence 
in LIFR conditions prevailing through mid-to-late morning. While 
ceilings will likely lift on the cusp of IFR/MVFR, low to moderate 
confidence on VFR being achieved this afternoon. Moderate confidence 
on LIFR conditions returning tonight; however, reasonable best case 
scenario is the approaching cold front lifts ceilings or mixes them 
out completely.

&&

.MARINE...
(Today through Wednesday)
Issued at 446 AM PDT Fri Oct 9 2026

Strong northerly breezes will spread into the northern waters this
morning 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...Sarment
MARINE...Sarment

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Prepared by Boulder-Creek.com Weather at: Fri Oct 9 10:30:03 PDT 2026