839
FXUS66 KMTR 140021
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
521 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.

&&

.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...
(00Z TAFS)
Issued at 502 PM PDT Wed Aug 13 2025

MVFR/IFR ceilings will continue through the remainder of the
evening and overnight for terminal close to the coastline, with
interior sites seeing the marine stratus move in between sunset
and midnight. All terminals will see similar transition times to
VFR on Thursday as the past couple of days, in the late
morning/early afternoon.

Vicinity of SFO...Robust onshore flow and gradient has allowed
MVFR ceilings to persist across the Bay Area most of the day with
MVFR/IFR ceilings likely to persist through mid/late morning
Thursday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...The ebb and flow of the marine layer
continues to drive the timing and extent of stratus coverage. As
the marine layer expanded today, stratus clouds lingered in
vicinity of KMRY most of the afternoon with a few hours of VFR.
IFR/LIFR ceilings can expected through through the overnight hours
into late morning/early afternoon Thursday with occasionally
breezy onshore winds.

&&

.MARINE...
(Today through Monday)
Issued at 241 PM PDT Wed Aug 13 2025

Moderate northwesterly breezes today will increase to become fresh
to strong on Thursday. Widespread 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 to become rough for the inner waters 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 until 9 PM PDT this evening for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm.

     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 from 9 PM this evening to 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...RGass

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