418
FXUS66 KMTR 031053
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
353 AM PDT Wed Sep 3 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 108 AM PDT Wed Sep 3 2025

 - Gradual cooling trend through the remainder of the week.

&&

.SHORT TERM...
Issued at 108 AM PDT Wed Sep 3 2025
(Today and tonight)

My oh my, what a difference in satellite imagery tonight. The
disturbance that brought us isolated thunderstorms and little to
no rain yesterday morning is currently sitting over northwest CA,
while stratus has started to blanket the CA coast. For us, stratus
has infiltrated some of the North Bay valleys of Sonoma and Marin
counties and is trying to creep in elsewhere. The marine layer
isn`t expected to get more than 1000-1500ft or so tonight, so any
stratus that does form should quickly retreat to the coast. Once
that occurs, look for sunny skies inland and for high temperatures
to be a few degrees cooler than yesterday.

&&

.LONG TERM...
Issued at 108 AM PDT Wed Sep 3 2025
(Thursday through Tuesday)

No major changes for the extended portion of the forecast. Upper
level troughing over the eastern Pacific will gradually move
westwards towards the PacNW, while upper level ridging builds over
that region. We`ll be on the periphery of troughing to potentially
quasi zonal flow during this period. The weather should be
relatively stagnant, with temperatures continuing the gradual
cooling trend. The marine layer should deepen to some extent as
well, perhaps around 1500-2000ft by the end of the week. Cloudy
nights and coastal drizzle will be possible.

For the weekend and into early next, upper level troughing looks to
nudge it`s way into the PacNW and perhaps far northern CA. Quiet and
cool weather will prevail. Another trough looks to work its way
towards the PacNW and far northern CA again by early next week which
may sway temperatures a few degrees cooler.

&&

.AVIATION...
(12Z TAFS)
Issued at 341 AM PDT Wed Sep 3 2025

Deeper marine layer at about 1500-2000 feet allowing for further
inland push of stratus this morning. However, despite the deeper
marine layer, it will take a while to restore enough moisture for
stratus formation after drier air was mixed in yesterday.
Anticipating patchy stratus to fill in around the Bay Area by
sunrise and linger into the late morning before mixing out to VFR.
Higher confidence in the return of MVFR/IFR stratus later this
evening given combo of deep marine layer and restored moisture.

Vicinity of SFO...Difficult forecast this morning as marine
stratus is anticipated to be patchy around the SF Bay. Introduced
a TEMPO group for BKN010, but confidence is low in coverage.
Higher probs in MVFR/IFR cigs later this evening into Thursday
morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Socked in MVFR cigs around the region
this morning. Moderate confidence in VFR timing with a slight
chance for brief LIFR cigs around sunrise. Rinse and repeat
tonight with cigs perhaps a bit lower into the IFR range.

&&

.MARINE...
(Tonight through next Monday)
Issued at 957 PM PDT Tue Sep 2 2025

Moderate to fresh northwest breezes prevail through Friday.
Strong northwesterly gusts will result in hazardous conditions for
small craft on Wednesday across the outer waters and coastal jet
regions. Moderate seas will prevail through Friday with occasional
rough seas in the outer waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Behringer
MARINE...DialH

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