121
FXUS66 KMTR 212208
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
308 PM PDT Fri Aug 21 2026

...New SHORT TERM, LONG TERM, MARINE...

.KEY MESSAGES...
Updated at 308 PM PDT Fri Aug 21 2026

 - Temperatures will be close to or below normal into the beginning
   of next week

 - Warm and dry conditions above 1000ft persist into the weekend

&&

.SHORT TERM...
Issued at 308 PM PDT Fri Aug 21 2026
(This evening through Saturday night)

The forecast is on repeat today. Satellite imagery shows high clouds
streaming overhead and the stratus a bit more dispersed along the
coast. Expect these conditions to continue this afternoon, with the
marine layer making a return later this evening and overnight.
Guidance shows the marine layer should be around 1000-1500ft across
our service area, which should lead to another night and morning of
cloudy skies for the majority of the valleys. Low clouds continue to
clear by mid to late morning, with a few high clouds potentially
lingering into Saturday. With stratus clearing potentially a bit
earlier and less high clouds, highs should be similar to Thursday,
perhaps a few degrees warmer. &&

.LONG TERM...
Issued at 308 PM PDT Fri Aug 21 2026
(Sunday through next Thursday)

The extended forecast looks similar, as we remain caught in the
quasi-zonal to weak troughing while high pressure holds to the east.
Temperatures should cool a few degrees on Sunday and then moderate
into early next week. Models and ensembles show ridging trying to
build slightly to the west, which would lead to warming for mid to
late next week. Some caveats to what might happen will be the
Pacific. The Tropical Weather Outlook from the National Hurricane
Center shows three potential disturbances well south of Baja. Could
influence how the high behaves.

&&

.AVIATION...
(18Z TAFS)
Issued at 1125 AM PDT Fri Aug 21 2026

Currently have a mix of IFR to VFR ceilings due to patchy stratus
across our region. VFR conditions are expected to prevail this
afternoon into the early evening hours. HAF is an exception as they
may have a couple hours of VFR scattered cloud decks in the early
afternoon before shifting back to IFR ceilings. Moderate to fresh
onshore breezes around 10 to 15 kt expected through the day and ease
overnight. The marine layer returns this evening impacting coastal
sites first before filling in over inland terminals. Low to medium
confidence on the exact stratus arrival as it is dependent on where
the upper level low sets up during the day. Currently, all TAF sites
are expected to develop IFR to MVFR ceilings, with coastal sites
having a high chance of dropping to LIFR in the overnight hours.

Vicinity of SFO...Stratus is beginning to mix out of the SF Bay as
moderate onshore breezes increase. VFR through the afternoon with
occasional gusts around 20-25 kt possible. Winds remain around 10 kt
overnight. Medium confidence on the timing of IFR ceilings as they
may arrive as early as sunset. The marine stratus is expected to
linger until late Saturday morning.

SFO Bridge Approach...Ceilings that develop may not be as low as SFO
and clear before SFO does. Otherwise, similar to SFO.

Monterey Bay Terminals...Stratus is receding to the coastline
resulting in VFR conditions through the afternoon. Onshore winds
will be diurnally driven this TAF period. The marine layer holds on
strong as it returns with IFR ceilings this evening around 6-7 PM
PDT. Medium confidence that ceilings will drop to LIFR overnight
(OVC003-004), but there is still uncertainty regarding the exact
timing and duration of LIFR conditions. If LIFR ceilings develop,
they are likely to impact visibility and linger at the terminals
through mid Saturday morning.

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 308 PM PDT Fri Aug 21 2026

Widespread moderate to fresh northwest breezes prevail through the
weekend with slight to moderate seas. Locally strong breezes with
occasional near gale force gusts are expected in the coastal jet
regions of Point Sur and Point Reyes. Hazardous conditions for
small  crafts are expected this afternoon for the bay waters and
immediate  coastal waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF
     Bay N of Bay Bridge.

     Small Craft Advisory until 3 AM PDT Sunday for Pt Arena to Pt
     Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt
     Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 2 PM Saturday to 3 AM PDT Sunday for
     Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60
     NM-Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Navarrete
MARINE...Navarrete

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea