282
FXUS66 KMTR 300736
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1236 AM PDT Wed Sep 30 2026

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

.KEY MESSAGES...
Updated at 1231 AM PDT Wed Sep 30 2026

 - Elevated fire weather conditions across the higher terrain
   through Thursday

 - Areas of moderate HeatRisk across the interior through Tuesday

 - Minor coastal flooding for bayshore locations along the San Francisco,
   San Pablo, and Monterey Bays Monday through Thursday

&&

.SHORT TERM...
Issued at 1231 AM PDT Wed Sep 30 2026
(Wednesday through Thursday)

With ridging nosing in from the Eastern Pacific Ocean and a low
across the Desert Southwest, the upper-level pattern will support
northerly/offshore flow through Thursday. Northerly/offshore winds
will be strongest during the overnight periods and in the higher
terrain. Mt. St. Helena gusted to 48 mph Tuesday morning with gusts
of 25-35 mph elsewhere, similar conditions can be expected during
the overnight periods through Thursday morning. The combination of
dry and windy conditions will result in elevated fire weather
conditions across the higher terrain through Thursday. Temperatures
will be 5 to 10 degrees above normal with the marine layer
struggling to form. If it is able to form, it will be compressed
around 500 feet and remain confined to the coast. Minor coastal
flooding for bayshore locations along the San Francisco, San Pablo,
and Monterey Bays will continue during the highest high tides
through Thursday.

&&

.LONG TERM...
Issued at 1231 AM PDT Wed Sep 30 2026
(Friday through Tuesday)

Global ensemble clusters are in agreement that anomalously high
heights will be across our area through Tuesday. 500 mb heights and
850 mb temperatures are forecast to be near the 90th percentile for
the first week of October, which is 588 decameters and 21 degrees
Celsius, respectively. Saturday will likely be the peak of the heat
as upper-level longwave ridging drifts in from the Eastern Pacific
Ocean. Nonetheless, temperatures will be 10 to 15 degrees above
normal with moderate HeatRisk away from the immediate coast through
Tuesday. The marine layer will likely still struggle to form; if
it`s able to form, it will be compressed around 500 feet and remain
confined to the coast.

&&

.AVIATION...
(06Z TAFS)
Issued at 954 PM PDT Tue Sep 29 2026

Currently VFR except MVFR at HAF. Moderate confidence on LIFR
conditions returning to the coastal terminals of HAF, MRY, and SNS
with lower confidence in the return at APC and STS, elsewhere VFR.
With stratus well offshore, this will likely be achieved via
radiational cooling. The best chances are between 08Z and 16Z,
more specifically when radiational cooling maximizes around
sunrise (14Z). Diurnal winds will prevail. Haze will reduce slant
range visibilities.

Vicinity of SFO...Currently VFR with westerly flow. High confidence
in VFR and diurnal winds prevailing through the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR with southwesterly flow at
MRY and VFR with northerly flow at SNS. Moderate confidence on LIFR
conditions returning tonight, best chances are between 08Z and 16Z.
Diurnal winds will prevail.

&&

.MARINE...
(Tonight through next Monday)
Issued at 954 PM PDT Tue Sep 29 2026

Hazardous conditions for small craft will continue through
Wednesday  night across the outer waters and coastal jet regions
of Point Reyes  and Point Sur. Frequent northerly gale force gusts
will continue  tonight across the northern outer waters.
Conditions will improve  Thursday and into the weekend as
northerly breezes diminish to  become gentle to moderate. Rough to
very rough seas Wednesday will  subside to become moderate by
Friday.

&&

.FIRE WEATHER...
Issued at 515 AM PDT Mon Sep 28 2026

The marine layer persists this morning, around 1500-2000ft, but
should gradually compress to around 500ft throughout the day.
Today will be coolest day of the week, though it is also the start
of a warming trend. Offshore flow gradually works its way into the
region today, which will lead to breezy winds each morning from through
Wednesday. The strongest winds are expected on Tuesday morning in
the interior mountains of the North and East Bays, where wind
gusts could reach 30-35 mph. These offshore winds should
contribute to poor overnight humidity recoveries, with overnight
relative humidities as low as 20-40% above the marine layer.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 5 PM PDT Thursday for CAZ006-506-
     508-529-530.

PZ...Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

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

     Gale Warning until 9 AM PDT this morning for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Sarment
MARINE...Sarment

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