FXUS66 KMTR 121156
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
456 AM PDT Mon Oct 12 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1123 PM PDT Sun Oct 11 2026
- Cool temperatures through Tuesday; warming trend and above
normal temperatures starting mid to late week
- Coastal flooding during high tides through mid-week
- Hazardous beach conditions continue through Monday evening due
to increased risk of sneaker waves, rip currents, and large
breaking waves
&&
.SHORT TERM...
Issued at 1123 PM PDT Sun Oct 11 2026
(Tonight through Tuesday)
Upper level troughing continues across the West Coast through mid-
week before the trough progresses eastward. If you stepped outside
today it likely felt like the first real breath of fall. Highs
largely peaked in the 60s to low 70s Sunday. Temperatures ran about
5 to 10 degrees below normal today with the 850 mb temperature (9C
at the 00Z launch) between the 10th and 25th percentiles. This trend
continues Monday with high temperatures in the 60s to low 70s and
overnight lows (Monday morning) largely in the 40s. The exception
will be across the higher elevations where a few locations may drop
into the 30s. For comparison, we typically see high temperatures in
the mid to upper 70s across the interior this time of year. By
Tuesday, the center of the upper level low will start to progress
eastward while upper level ridging starts to rebuild along the
coast. This will kick off a slight warming trend (2-4 degrees) and
bring more interior locations into the low to mid 70s while coastal
areas stay in the 60s. Low temperatures Tuesday morning will be
similar to Monday with lows in the 40s to low 50s across most of the
region and pockets of 30s across the higher elevations.
Light rain is possible along the Big Sur Coast and southern Monterey
County early Monday morning but no real accumulation is expected.
More typical onshore winds return Monday as the SFO-WMC pressure
gradient shifts positive (onshore) again. Diurnally breezy winds
continue for favored locations (coastal areas, mountain gaps and
passes) and over the marine environment. Fire weather concerns
diminish Monday/Tuesday given the decreasing winds and improved
daytime humidity values. A Coastal Flood Advisory remains in effect
through 3PM Tuesday but may need to be extended into Wednesday for
the entire bay shoreline. It will depend on how high tides get
Monday/Tuesday and if tidal heights are trending down enough for the
advisory to be expired on time Tuesday night.
&&
.LONG TERM...
Issued at 1123 PM PDT Sun Oct 11 2026
(Tuesday night through next Sunday)
Our brief glimpse of fall will quickly become a distant memory by
late week as temperatures heat up again. The upper level trough
continues to progress eastward Tuesday into Wednesday with upper
level ridging becoming dominant Wednesday onwards. Much warmer
temperatures are expected for the second half of the week with above
normal temperatures returning Thursday into the weekend. Wednesday
will be a transition day between cooler early week temperatures and
hot late week temperatures with seasonal to slightly above normal
temperatures anticipated. High temperatures will be 10 to 15 degrees
above normal Thursday through Saturday. Interior locations will be
in the 80s to 90s while coastal areas peak in the 70s to low 80s.
Much drier conditions are expected late week with a return of
daytime humidity values dropping into the 10s. Elevated fire weather
conditions are likely late week as much warmer and drier conditions
return. Fortunately, no major signals that winds will be gusty
around this time which should help mitigate at least some of the
risk. As always, if you are participating in an activity that
involves fire or towing anything, make sure to prevent sparks from
spreading as fuels are very dry/flammable. Moderate HeatRisk returns
late week into the weekend so make sure to take breaks in the shade,
drink plenty of water, and reduce time outdoors during peak
heating.
&&
.AVIATION...
(12Z TAFS)
Issued at 450 AM PDT Mon Oct 12 2026
VFR is expected to prevail through the forecast for all
terminals. Weak offshore flow today from a weak otter eddy will be
reinforced by larger scale ridging over the EPAC and progressive
upper closed low to our west diving south that will begin to drive
more offshore flow by the end of the forecast period.
Vicinity of SFO...VFR. Offshore flow and lack of a marine layer
will result in mainly clear skies through the TAF period.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR is expected to prevail through the
forecast period with the aforementioned periods of offshore flow.
&&
.MARINE...
(Today through Saturday)
Issued at 450 AM PDT Mon Oct 12 2026
Sea state will gradually improve today as northwest winds
decrease across our coastal waters, however buoys are still
reporting rough seas early this Monday morning. Long period swell
increases to 16ft to 18ft by early Tuesday morning and gradually
decreases through the rest of the work week.
&&
.BEACHES...
Issued at 1042 AM PDT Sun Oct 11 2026
Buoy reports this morning still indicated some solid swell
entering the coastal waters. As such, still seeing an energetic
the surf zone. Give the observed height and period isolated
breaking waves 18-20 ft are possible at favored break points. Long
period southerly swell will persist through the weekend, bringing
an increased risk of sneaker waves and strong rip currents. 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!
MM
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through 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 9 AM PDT this morning for Pt Arena to
Pt Reyes 0-10 nm.
Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt
Reyes 10-60 NM.
Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt
to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...JM
MARINE...JM
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Prepared by Boulder-Creek.com Weather at: Mon Oct 12 08:30:04 PDT 2026
From the National Weather Service
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