Technical NOAA Weather Discussion

FXUS66 KMTR 130448
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
948 PM PDT Mon Oct 12 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 118 PM PDT Mon Oct 12 2026

 - Cooler weather through tomorrow; warming trend and above normal 
   temperatures starting mid to late week

 - Coastal flooding during high tides through midweek

 - Hazardous beach conditions through this evening due to sneaker 
   waves, rip currents, and breaking waves

 - Elevated fire weather conditions mid to late week for higher
   elevations

&&

.SHORT TERM...
Issued at 118 PM PDT Mon Oct 12 2026
(This evening through Tuesday night)

An upper level trough dominates much of the West Coast's weather 
this afternoon as the closed low sits over the PacNW and broad 
troughing extends southward through California. To it's west, over 
the eastern Pacific, high pressure is being observed. Satellite 
imagery shows these too features quite well, with visible satellite 
showing the base of the trough over Central and Southern California. 
Most of our skies this afternoon remain clear; however, if you're in 
the interior Central Coast region, you may see some small puffs of 
cumulus clouds building over the ridges. So far there hasn't been 
any measurable rain reported or observed, likely due to the dry air 
in place and limited cloud growth. 

Tonight, look for skies to clear and for another chilly fall night. 
Temperatures should generally similar to or a few degrees higher 
than last night. Tuesday's forecast will be similar to today, though 
skies across the region should be mostly clear with high 
temperatures being a few degrees warmer than today.

&&

.LONG TERM...
Issued at 118 PM PDT Mon Oct 12 2026
(Wednesday through next Sunday)

An upper level high pressure system over the eastern Pacific will 
continue to build and expand eastward towards the West Coast. This 
will help push the upper level trough out of the region late Tuesday 
into Wednesday. During this time frame we will see a period of 
offshore flow during the overnight hours. As the high continues to 
build and the low moves east, each night will bring a renewed chance 
of these offshore winds. Especially late in the week, as the upper 
level trough elongates and then splits. When this occurs, the trough 
situates over the Desert Southwest and around southern California. 
Ridging remains over the northern half of the state which should lead 
to an increase of offshore flow and our warming trend. Ensembles and 
models then show signals of quasi-zonal flow and weak ridging for 
the weekend. Temperatures should decrease in response to the pattern 
change. For fire weather concerns, please see the fire weather 
discussion below.

&&

.AVIATION...
(06Z TAFS)
Issued at 948 PM PDT Mon Oct 12 2026

Generally VFR conditions prevail with the exception of patchy MVFR 
stratus, sea spray and haze along the immediate coast and a low 
confidence for radiational fog at STS early Tuesday morning. Light 
winds will continue through the night into the morning before gentle 
to moderate winds resume Tuesday afternoon, with a more northwest to 
west flow in the coastal areas to a more northerly breeze in the 
interior.

Vicinity of SFO... VFR at the terminal through the TAF period. 
Gentle northwest flow will continue into the overnight period, with 
light offshore flow developing Tuesday morning before the northwest 
winds resume in the afternoon.

SFO Bridge Approach... Similar to SFO. 

Monterey Bay Terminals... Moderate to high confidence of VFR through 
the TAF period. Light drainage winds persist into Tuesday morning 
before gentle to moderate northwest winds resume in the afternoon.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 948 PM PDT Mon Oct 12 2026

Gentle to fresh northerly breezes persist over the coastal waters
through Friday. The strongest winds remain over the outer waters
north of Point Reyes. The overall sea state will improve as well
as the northwest swell diminishes. However, some moderate to
longer period southerly swell mixes in through the week.

&&

.FIRE WEATHER...
Issued at 118 PM PDT Mon Oct 12 2026

There will be a few bursts of offshore winds this week, generally 
during the overnight hours. The first burst looks to occur tonight, 
particularly highlight the interior North Bay Mountains, where we 
could see gusts range from 20-35 mph, perhaps even up to 40 mph for 
the exposed ridges and the higher elevations. After that, the next 
area of concern we are monitoring is Wednesday night into Thursday 
morning, where the pressure gradient should be a bit more tight due 
to upper level wind patterns. Majority of the area should see 
offshore flow, in the north to northeast component , with gusts 
closer to 25-35 mph, locally higher perhaps up to 45 mph for exposed 
ridges, gaps, and passes. Warm and dry weather will be on tap as 
well, which will lead to an elevated threat for the higher terrain 
areas. Another round of offshore winds is expected Thursday night 
into Friday, but appears to be weaker than the previous two. 

&&

.BEACHES...
Issued at 1031 AM PDT Mon Oct 12 2026

Compare to the last few days conditions along the coast are
gradually improving as longer period swell trains are decreasing.
However, buoy reports Monday morning continue to advertise
moderate to longer period swells (albeit smaller heights) 
entering the coastal waters. As such, elevated surf zone 
conditions lingering. Additionally, moderate period west-northwest
swell will arrive Monday afternoon lingering into Monday evening.
As such, Beach Hazard Statement remains in effect through this 
evening. 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.
Never turn your back on the ocean!

MM

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement until 10 PM PDT this evening for CAZ006-
     505-509-529-530.

     Coastal Flood Advisory until 3 PM PDT Tuesday for CAZ006-508-529-
     530.

     Coastal Flood Advisory until 4 PM PDT Wednesday for CAZ506.

PZ...Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...DialH
MARINE...DialH

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Prepared by Boulder-Creek.com Weather at: Mon Oct 12 22:30:03 PDT 2026
From the National Weather Service