FXUS66 KMTR 031716
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1016 AM PDT Sat Oct 3 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1243 AM PDT Sat Oct 3 2026

 - Moderate to major HeatRisk across the Bay Area and Central
   Coast Saturday and Sunday

 - Moderate to major HeatRisk across the interior Bay Area and 
   Central Coast Monday through Thursday

 - Elevated fire weather conditions across the higher terrain
   through Thursday

&&

.SHORT TERM...
Issued at 1243 AM PDT Sat Oct 3 2026
(Saturday and Sunday)

The 00Z sounding observed an 850 mb temperature of 22.95 degrees 
Celsius and a 500 mb height of 5900 meters, both of these are above 
the 90th percentile. The heat will peak this weekend as an upper-
level longwave ridge drifts in from the Eastern Pacific Ocean. A 
Heat Advisory will go into effect at 11 AM Saturday and run through 
10 PM Sunday for most of the Bay Area and Central Coast. It was 
extended in area to include the Carmel Valley, Hollister Valley, 
Marin Coastal Range, Northern Monterey Bay, Northern Salinas Valley, 
and San Francisco. Now, the only places that are not included is the 
North Bay Coast, San Francisco Peninsula Coast, and Southern 
Monterey Bay; this is banking on a compressed marine layer keeping 
these spots cool. If the compressed marine layer is able to survive, 
expect reduced visibility from fog along the coast. If it is not 
able to survive, coastal conditions will be hotter than currently 
forecast. Moderate to major HeatRisk will result from maximum 
temperatures 10 to 20 degrees above normal. Minimum temperatures 10 
to 20 degrees above normal with weaker than normal onshore flow will 
bring limited relief overnight, also contributing to HeatRisk. Even 
less relief is expected in the higher terrain where elevated fire 
weather conditions continue with hot and dry conditions, prominent 
thermal belting, and prolonged burn periods.

&&

.LONG TERM...
Issued at 1243 AM PDT Sat Oct 3 2026
(Monday through Friday)

The Heat Advisory will remain in effect through 10 PM Monday for the 
interior Bay Area and Central Coast. Upper-level shortwave troughing 
will undercut the ridge and bring an increase in onshore flow 
Monday; however, the interior will remain hot. Global ensemble 
clusters are in agreement that heights will rebuild Tuesday and peak 
Wednesday. With little change in the day-to-day forecast and the 
cumulative heat impacts, we could be looking at an extended Heat 
Advisory. This is especially true for the East Bay and South Bay 
where major HeatRisk is likely (60%+) through Wednesday. The marine 
layer will remain compressed during this time, keeping the coast 
cool and likely reducing visibility from fog. Elevated fire weather 
conditions will continue in the higher terrain through Thursday for 
hot and dry conditions with prominent thermal belting and prolonged 
burn periods. Thursday remains uncertain on ridge vs. trough, but by 
Friday it is likely that heights will begin to fall.

&&

.AVIATION...
(18Z TAFS)
Issued at 1015 AM PDT Sat Oct 3 2026

High pressure strengthening over the region will result in 
continued VFR conditions throughout the day today with weak 
onshore flow returning by mid-afternoon before easing overnight. 
The greatest potential for sub-IFR conditions will be around the 
Monterey Bay terminals late tonight into early Sunday morning, 
however confidence is low to moderate. 

Vicinity of SFO...VFR. Weak offshore winds currently with weak 
onshore flow expected by mid-afternoon. Winds ease overnight and 
into early Sunday morning with generally high confidence of VFR 
conditions persisting through the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Moderate drainage winds currently 
at SNS will shift onshore by early afternoon and prevail through 
this evening. The greatest potential for sub-IFR conditions will 
be at MRY late tonight and into early Sunday morning, less 
confidence for SNS. Any low clouds and/or fog that does develop is
likely to dissipate by 15Z Sunday. 

&&

.MARINE...
(Today through Thursday)
Issued at 1015 AM PDT Sat Oct 3 2026

Northerly to northwesterly breezes remain gentle to moderate into
early week, allowing for slight to moderate seas to persist.

&&

.FIRE WEATHER...
Issued at 458 AM PDT Sat Oct 3 2026

Hot and dry conditions are forecast through next week, which will
be accompanied with weak offshore flow. Poor to very poor 
overnight recovery is expected for the thermal belts, generally 
for elevations above 1000-1500 feet, leading to elevated fire 
weather conditions. The marine layer is expected to be confined to
the immediate coast and around 500 feet. A pattern change begins 
late Thursday into Friday, which may lead to cooler weather and 
the potential for improved RH recovery.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 10 PM PDT Sunday for CAZ006-502-528-529.

     Heat Advisory until 10 PM PDT Monday for CAZ503-504-506-508-510-
     512>518.

PZ...None.
&&

$$

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

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Prepared by Boulder-Creek.com Weather at: Sat Oct 3 10:30:04 PDT 2026