FXUS66 KMTR 102337
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
437 PM PDT Thu Sep 10 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1215 PM PDT Thu Sep 10 2026
- Widespread moderate HeatRisk continues through this evening
- Cooler temperatures, closer to seasonal averages, Friday into
the weekend
- Breezy onshore winds forecast for this weekend
&&
.SHORT TERM...
Issued at 1215 PM PDT Thu Sep 10 2026
(This evening through Friday night)
After a warm start to the day, the interior will remain very warm
to hot with the ongoing Heat Advisory still in place until 10 PM
PDT this evening. However, we are already seeing cooler conditions
near the coast as a shallow marine layer is forecast to return as
well as an increase in onshore winds.
Tonight, temperatures are forecast to cool into the mid 50s to
near 60 deg F near the coast and across the interior valleys.
However, the higher elevations look to only cool into the 70s and
potentially the lower 80s. Coastal stratus and/or fog look to
develop along the coast and potentially into the North Bay Valleys
overnight as the marine layer deepens to around 500 feet.
On Friday, depending on how much stratus/fog develops in the
morning, the cooling trend will continue with temperates
moderating to near seasonal averages with mostly sunny conditions
across the interior. This is a result of the mid/upper level
through deepening off of the Pacific Northwest coast and high
pressure over the Desert Southwest being suppressed to the south.
&&
.LONG TERM...
Issued at 1215 PM PDT Thu Sep 10 2026
(Saturday through next Wednesday)
The gradual cooling trend will continue into the weekend as the
low pressure off of the Pacific Northwest coast deepens further,
bringing rainfall to that region. This will allow the marine layer
to deepen as well, reaching around 1500 feet by Saturday night
into Sunday. This would also bring increased afternoon and evening
winds in the favored valleys, peaks, passes, and gaps.
Beyond this weekend, troughing off of the West Coast looks likely
to persist. This will allow for afternoon maximum temperatures to
be near to slightly below average and overnight minimum
temperatures to be near or slightly above.
&&
.AVIATION...
(00Z TAFS)
Issued at 428 PM PDT Thu Sep 10 2026
VFR through this evening with gusty onshore flow. Clouds along the
coast this afternoon is the return of marine layer. Expect the
marine layer to push in tonight and early Friday, but remain
compressed. As such, low chc for fog late tonight. Additionally,
expect an earlier clearing time on Friday. Overall conf is
moderate.
Vicinity of SFO...Breezy NW winds this evening with VFR. Will take
some time, but clouds will move through the GG and push through
OAK and SFO by Friday AM. MVFR early Friday with clearing during
the AM rush.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...MVFR/IFR returns early tonight and then
lingering through mid morning Friday. VFR Friday afternoon.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 428 PM PDT Thu Sep 10 2026
High pressure to north and low pressure to the south will maintain
a moderate to fresh northwesterly breeze through Friday,
increasing to become fresh to strong this weekend into next week.
Locally hazardous conditions for small craft today will expand to
become widespread this weekend into next week. Moderate seas will
prevail through the weekend, building to become rough in the outer
waters Monday. A longer period southerly swell will mix into the
sea state due to tropical systems in the Pacific.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 10 PM PDT this evening for CAZ006-502>506-
508>510-512>518-528>530.
PZ...Small Craft Advisory from 3 AM Friday to 3 AM PDT Saturday for
Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 AM to 9 PM PDT Friday for Pigeon Pt
to Pt Pinos 0-10 nm.
Small Craft Advisory until 3 AM PDT Saturday for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...MM
MARINE...MM
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Prepared by Boulder-Creek.com Weather at: Thu Sep 10 20:30:03 PDT 2026
From the National Weather Service
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