FXUS66 KMTR 290452
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
952 PM PDT Mon Sep 28 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1205 PM PDT Mon Sep 28 2026

 - Elevated fire weather conditions across the higher terrain
   through Wednesday

 - Areas of moderate HeatRisk across the interior Wednesday
   through Sunday

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

&&

.SHORT TERM...
Issued at 1205 PM PDT Mon Sep 28 2026
(This evening through Tuesday night)

The stratus has largely cleared out with some isolated patches 
continuing at the immediate coast. Probability of stratus 
development tonight is low to very low, as incoming ridging and 
offshore flow will generally disrupt the marine layer stratus 
formation processes. 

The latest water vapor imagery shows an upper level low tracking 
across the southern Central Valley into the Mojave Desert, expected 
to continue trekking southeastward through the day and entering 
Arizona by Tuesday morning. Behind the low, an incoming ridge 
kickstarts a warming trend that will extend through the next couple 
of days. Today's high temperatures range from the middle 70s to 
middle 80s inland to the upper 60s to middle 70s along the Bays and 
the lower to middle 60s at the Pacific coast. On Tuesday, high 
temperatures will reach the middle 80s to middle 90s inland, the 
middle 70s to middle 80s along the Bays, and the middle 60s to lower 
70s at the Pacific coast.

With the northerly flow aloft as the upper level low moves towards 
the southeast, a push of offshore wind is expected in the higher 
elevations Tuesday morning. Gusts of 25 to 35 mph are expected along 
the exposed ridgelines, and stronger gusts are possible along the 
ridge of the Vaca Mountains along the Napa-Yolo and Napa-Solano 
county lines. Elsewhere, generally diurnal winds will prevail with 
onshore winds developing each afternoon and evening, with gusts to 
30 mph along the coast, through favored gaps and passes, and within 
the Salinas Valley. 

Minor coastal flooding is possible across the bayshore locations of 
San Francisco Bay, San Pablo Bay, and Monterey Bay around high tide 
starting today. Up to 1.2 feet of inundation above normally dry land 
is expected, including up to 0.6 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 1.0 ft above normal (6.87 ft MLLW) at 12:57 PM Monday 9/28 
and 1.2 ft above normal (7.01 ft MHHW) at 1:30 PM Tuesday 9/29.

&&

.LONG TERM...
Issued at 1205 PM PDT Mon Sep 28 2026
(Wednesday through next Sunday)

There is an additional push of higher elevation offshore flow on 
Wednesday morning. This push will be more focused on the interior 
mountains of the North and East Bay with gusts a little lighter than 
those expected on Tuesday morning. Otherwise, temperatures may 
fluctuate by a few degrees each day, most notably on Thursday when 
stronger onshore flow will cause some of the coastal regions to dip 
by a few degrees, but the general trend should remain similar to 
Tuesday's highs through the end of the seven day outlook. Areas of 
Moderate HeatRisk, a level of heat that brings a moderate risk of 
heat-related illnesses to sensitive populations, develop across the 
interior regions Wednesday through Saturday, but confidence in 
widespread impacts is not high enough to issue a Heat Advisory at 
this point. Longer-range guidance suggests that temperatures above 
the seasonal average will continue into the second week 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 1.2 ft above normal (7.03 
ft MHHW) at 2:10 PM Wednesday 9/30, and 1.1 ft above normal (6.92 ft 
MHHW) at 2:58 PM on Thursday 10/1. 

&&

.AVIATION...
(06Z TAFS)
Issued at 950 PM PDT Mon Sep 28 2026

Currently IFR-VFR. The little stratus that is along the immediate 
coast is eroding and is expected to continue to do so as 
northerly/offshore flow develops overnight. Therefore, TAFs may be 
too pessimistic with HAF and MRY hanging onto IFR/MVFR ceilings 
through mid-to-late morning. Diurnal winds will prevail with light 
northerly/offshore flow overnight.

Vicinity of SFO...Currently VFR with westerly flow. High confidence 
in VFR through the TAF period. Winds will diminish to become light 
and potentially variable overnight; however, the direction will 
likely favor either westerly or northeasterly.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently IFR with southwesterly flow at 
MRY and VFR with northerly flow at SNS. Stratus is actually on an 
eroding trend with tonight likely dependent on an Otter Eddy in 
Monterey Bay. Reasonable best case scenario is VFR, reasonable worst 
case scenario is subsidence aloft compresses the marine layer and 
brings LIFR ceilings/visibilities. Diurnal winds will prevail.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 950 PM PDT Mon Sep 28 2026

Strong to very strong northerly breezes will create hazardous
conditions for small craft across the coastal waters. Frequent
gale  force gusts are expected across the northern waters through
Wednesday morning. Conditions will begin to improve Wednesday
night  as northerly breezes diminish to become gentle to moderate,
with  locally hazardous conditions across the northern outer
waters likely  to continue. 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...Small Craft Advisory until 3 PM PDT Tuesday for Pt Arena to Pt 
     Reyes 0-10 nm.

     Gale Warning from 3 PM to 9 PM PDT Tuesday for Pt Arena to Pt 
     Reyes 0-10 nm.

     Small Craft Advisory from 9 AM Tuesday to 3 AM PDT Wednesday for 
     Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 3 AM PDT Wednesday for Pt Pinos to Pt 
     Piedras Blancas 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...Sarment
MARINE...Sarment

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Prepared by Boulder-Creek.com Weather at: Mon Sep 28 22:30:03 PDT 2026