603
FXUS66 KMTR 140502
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1002 PM PDT Wed Aug 13 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 1200 AM PDT Wed Aug 13 2025

 - A pattern change will bring a more robust marine layer, cooler
   temperatures, and some morning drizzle today.

 - Strong NW winds will arrive to the coast Thursday and spread
   inland Friday.

 - Temperatures will climb slightly through Friday before cooling
   again this weekend.

&&

.UPDATE...
Issued at 904 PM PDT Wed Aug 13 2025

Satellite imagery shows the marine layer stratus deck building
into the Sonoma County valleys, flowing through the Golden Gate
into the East Bay, and expanding across the Monterey Bay region
and up the Salinas Valley. The forecast remains on track with no
changes at this time.

DialH

&&

.SHORT TERM...
Issued at 200 PM PDT Wed Aug 13 2025
(This afternoon through Thursday)

Decent 24 hour trends this afternoon weather wise across the
forecast area. We`ve been discussing the pattern change for a few
days now and this is it. Temperatures continue to cool across the
region. Some interior locations are 10 to 15 degrees cooler than
Tuesday. All that being said, far interior E Bay and far interior
Central Coast temperatures are cooler, but still in the 90s with
a 10-20% chc at breaking 100 degrees. On the flip side, going to
the coast? Bring a jacket. Clouds linger and temps are stuck in
the upper 50s to 60s.

No major changes through the short term. Additional cooling with
persistent marine layer.

&&

.LONG TERM...
Issued at 203 PM PDT Wed Aug 13 2025
(Thursday night through next Tuesday)

An upper level trough will become anchored over the west through
the weekend and into early next week. Basically, a rinse and
repeat forecast and pattern we`ve see a lot of this summer.
Night/morning clouds clearing to the coast each afternoon. Cooler
coast and seasonably cool inland, even with sunshine. Only weather
impact of note will be increasing winds Thursday night and
Friday. While upper level troughing dominates, weak surface high
pressure noses into the CA/OR. As such, the N-S gradient ramps up
along NorCal. In response to the increase pressure gradient winds
increase. Not strong enough for a wind advisory, but still windy
along the coast, oriented N-S valleys, and inland gaps/passes.
Gusts of 30-40 mph are possible. Winds finally ease by Saturday.

&&

.AVIATION...
(06Z TAFS)
Issued at 1001 PM PDT Wed Aug 13 2025

Breezy onshore flow coupled with the marine layer gradually
increasing this evening, has resulted in low stratus pushing farther
inland than at this time twenty four hours ago. Expect MVFR/IFR
ceilings to persist through the overnight with occasional drops to
LIFR for the North Bay and Bay Area possible, more confident for
periods of LIFR at the Monterey Bay terminals.

Vicinity of SFO...Expect MVFR/IFR ceilings to persist through the
overnight until early Thursday afternoon with an expanding marine
layer and breezy onshore flow. The window for VFR on Thursday
afternoon will likely be smaller than the previous couple of days.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR will continue through the overnight,
with a period of LIFR expected in the hours surrounding sunrise
Thursday morning. Low confidence in the timing of VFR Thursday
afternoon if there is any. MVFR ceilings may persist through the
afternoon and, if so, until the end of the TAF period.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 904 PM PDT Wed Aug 13 2025

Moderate northwesterly breezes overnight will increase to become
strong on Thursday. Hazardous conditions will be present Thursday
with gale force gusts across the outer waters and along the
coastal jet region of Point Reyes and near-gale force gusts across
the rest of the inner waters. Moderate seas will increase on
Friday, becoming rough across both the inner and outer waters
through Friday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Thursday for SF Bay N of Bay
     Bridge.

     Small Craft Advisory from 9 AM to 3 PM PDT Thursday for Pt Arena
     to Pt Reyes 0-10 nm.

     Gale Warning from 3 PM Thursday to 3 AM PDT Friday for Pt Arena
     to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 3 PM Thursday to 3 AM PDT Friday for
     Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 3 PM to 9 PM PDT Thursday for Pigeon
     Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 AM PDT Friday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 PM PDT Thursday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory from 9 AM to 9 PM PDT Thursday for Pigeon
     Pt to Pt Pinos 10-60 NM.

     Gale Warning from 9 PM Thursday to 3 AM PDT Friday for Pigeon Pt
     to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...JM
MARINE...JM

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