781
FXUS66 KMTR 292318
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
418 PM PDT Tue Sep 29 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1229 PM PDT Tue Sep 29 2026

 - Elevated fire weather conditions across the higher terrain
   through Wednesday

 - Areas of moderate HeatRisk across the interior Wednesday
   through Tuesday

 - Minor coastal flooding near high tide for bayshore locations
   along the San Francisco, San Pablo, and Monterey Bays today
   through Thursday

&&

.SHORT TERM...
Issued at 1229 PM PDT Tue Sep 29 2026
(This evening through Wednesday night)

Isolated patches of stratus and fog linger along the coast, but the
region remains generally clear. With the marine layer compressing in
response to incoming ridging, any stratus development tonight is
limited to the coastal regions, with fog development possible along
the coast.

A pattern change is underway as ridging over the eastern Pacific
builds into the western United States, with temperatures warming
above to significantly above the seasonal averages (5 to 15 degrees
warmer) as a result. High temperatures today will be in the middle
80s to the middle 90s for the inland valleys, the middle 70s to the
middle 80s near the Bays, and the middle 60s to the lower 70s for
the Pacific coast. Wednesday`s highs will be similar. A breezy
onshore flow should set up each afternoon and evening, while the
overnight and morning period will feature a push of offshore flow
across the interior mountains of the North and East Bay.

Beginning today and especially Wednesday, areas of Moderate HeatRisk
start to pop up across the inland regions. These correspond to a
moderate risk of heat-related illnesses for sensitive populations,
including children, the elderly, pregnant women, people with chronic
illnesses, and people who work or live outdoors without access to
adequate cooling or hydration. These areas are not widespread enough
to put out a Heat Advisory, but still impact several populated
regions, notably the interior valleys of the East Bay and the San
Jose region. Follow these tips to avoid heat exhaustion and
heatstroke:

* Stay hydrated and drink plenty of fluids.
* Wear lightweight, light-colored clothing.
* Reduce time spent outdoors or stay in the shade.
* Never leave people or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

Minor coastal flooding is possible across the bayshore locations of
San Francisco Bay, San Pablo Bay, and Monterey Bay around high tide.
Up to 1.2 feet of inundation above normally dry land is expected,
including up to 0.7 ft of surge caused by thermal expansion and sea
level rise since the sea level datum (basically the point where we
define as "sea level") was set in the 1983-2001 period. At the San
Francisco tidal gauge, high tide is expected to be 1.2 ft above
normal (7.01 ft MLLW) at 1:30 PM Tuesday 9/29 and 1.2 ft above
normal (7.03 ft MLLW) at 2:10 PM Wednesday 9/30.

&&

.LONG TERM...
Issued at 1229 PM PDT Tue Sep 29 2026
(Thursday through next Monday)

Little change in the sensible weather through the week as a rather
resilient ridge sets up across the western United States, supported
by the ensemble model cluster analysis and the ensemble model means
from the European, American, and Canadian ensemble models.
Temperatures may fluctuate a few degrees owing to fluctuations in
the upper level pattern, but for the most part, high temperatures
through the seven day outlook should be similar to today`s highs.
The current forecast even suggests a few degrees of warming for the
upcoming weekend, with warm spots in the interior valleys reaching
the upper 90s and even some isolated triple digits. This is also
when we start to see more widespread areas of Moderate HeatRisk,
although it`s a little early to put out a Heat Advisory. Longer
range outlooks suggest that temperatures above seasonal averages
will continue into the middle of October.

Minor coastal flooding around high tide continues in low-lying areas
across the San Francisco, San Pablo, and Monterey Bay shorelines
through Thursday and potentially into Friday. At the San Francisco
tidal gauge, high tide is expected to be 1.1 ft above normal (6.92
ft MLLW) at 2:58 PM on Thursday 10/1.

&&

.AVIATION...
(00Z TAFS)
Issued at 417 PM PDT Tue Sep 29 2026

VFR conditions prevail across most of the region through the night
and into Wednesday. Some IFR-LIFR ceilings are possible overnight
and early Wednesday morning at the immediate coast and particularly
near Monterey Bay, while a low confidence for foggy conditions
exists within the North Bay valleys. A moderate onshore wind
continues through the evening hours, diminishing overnight before
gentle to moderate onshore winds resume Wednesday afternoon.

Vicinity of SFO... VFR through the TAF period. Breezy and gusty
northwest winds continue into the late evening hours, diminishing
overnight before resuming Wednesday afternoon.

SFO Bridge Approach... Similar to SFO

Monterey Bay Terminals... VFR through the late evening with IFR-LIFR
stratus developing after midnight, clearing after sunrise on
Wednesday morning. A gentle to moderate onshore wind continues
through the evening hours, with light winds overnight before gentle
onshore winds resume Wednesday afternoon.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 417 PM PDT Tue Sep 29 2026

Hazardous conditions prevail over the coastal waters due to fresh
to near gale northerly breezes. Frequent gale force gusts are
expected over the outer waters north of Pigeon Point through
Wednesday morning. Conditions will gradually improve Wednesday
night as northerly breezes ease to gentle to moderate. Rough to
very rough seas through Wednesday will subside to become moderate
to rough.

&&

.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...Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
     Reyes 0-10 nm.

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

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

     Small Craft Advisory until 3 PM PDT Wednesday for Pigeon Pt to
     Pt Pinos 10-60 NM.

&&

$$

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

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