FXUS66 KMTR 091931
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
Issued by National Weather Service Eureka CA
1231 PM PDT Wed Sep 9 2026

...New AVIATION, MARINE...

.KEY MESSAGES...

 - Warming and drying trend will bring widespread moderate to
   major HeatRisk through Thursday

 - Cooler temperatures, closer to normal, Friday into the weekend

&&

.SHORT TERM...(Today through Friday)

A northward intrusion of mainly mid and high level tropical 
moisture from the remnants of Marie continues through the North
Bay Area with more filling in overnight. Warm temperatures will 
continue tonight with the incoming cloud layers greatly reducing 
radiative cooling. Sub- cloud layer dry air does at times tend to 
stay land- locked over the highly varied terrain of CA, until 
diurnal mixing, diffusion, wind transport and/or precipitation get
going to thoroughly mix in the higher humidity to ground level.
The radar KMUX currently shows showers moving by about 70 miles 
offshore. This bears close monitoring in the nearest term.

No changes to the forecast at this time. A Heat Advisory remains
in effect for the entire forecast area until 10 PM Thursday. Strong
high pressure will result in warm morning low temperatures and 
daytime highs in the 90s to lower 100s over much of the forecast 
area. Along the immediate coastline an afternoon sea breeze may 
help nudge temperatures back down. This is a complex pattern, 
please stay tuned for the latest updates. Cooler, more seasonal 
temperatures are expected by Friday.

From the earlier forecast discussion:

Please remember these tips to help mitigate impacts from heat 
exposure:

-Suspend unnecessary outdoor activities during the extreme heat, but 
if you must be outdoors, take frequent breaks in the shade  or AC 
and drink cool water.
-Know the signs and symptoms of Heat Exhaustion vs. Heat Stroke! 
Heat Stroke can be deadly if not treated immediately by a medical 
professional. Call 911 if you suspect someone is suffering from Heat 
Stroke.
-Wear a life jacket, swim near a lifeguard, and check conditions 
before entering the water if going to a river or ocean to cool off. 
Rivers and the ocean are extremely cold, and Cold Water Shock can 
turn into paralysis and drowning if you are not careful.
-Use a cool and damp towel on your body if you do not have AC and 
are feeling hot. Or, take a cool shower or bath.
-Do not leave kids or pets in a parked car.
-Ensure pets and livestock have access to shade and water.

&&

.LONG TERM...(Saturday through next Wednesday)

The main concern is the short term. 

A weekend cooling trend remains in the forecast. The strong ridge
over our forecast area will weaken. Dry weather is forecast.

&&

.AVIATION...(18Z TAFS) 

VFR conditions are expected to continue as mid to high clouds
continue through the region. Light offshore flow will continue to
disrupt the marine layer today. These factors are both 
contributing to the high confidence VFR forecast across the 
terminals today. An afternoon sea breeze will easily overpower the
offshore gradient, with a moderate to fresh breeze expected in 
the afternoon and evening. More consistent onshore flow is 
expected to return by Thursday, bringing low clouds back into 
play.

Vicinity of SFO...High confidence in VFR conditions through the TAF 
period. Winds are currently light and variable, but the NW sea 
breeze will take hold this afternoon. Gusty NW winds potentially 
up to 15 kts could occur this afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR conditions are anticipated to 
persist through the TAF period with mid to high clouds returning
overnight. Light drainage winds in the morning will flip to a 
moderate onshore breeze in the afternoon. 

&&

.MARINE...as of 11:41 AM PDT Wednesday...A moderate NW breeze and
moderate seas will continue through Thursday. By Friday, a 
tighter pressure gradient will cause a steady increase in wind 
speed through the weekend, with a strong NW breeze expected 
Saturday and Sunday. A moderate SW swell from distant tropical 
cyclones will continue through the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
 .Tngt...Heat Advisory...CAZ006-502>506-508>510-512>518-528>530 
Coastal Flood Advisory...CAZ006-506-508-529-530

&&

$$

PUBLIC FORECAST: Default
AVIATION/MARINE: Default

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Prepared by Boulder-Creek.com Weather at: Wed Sep 9 16:30:02 PDT 2026