583
FXUS66 KMTR 221129
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
429 AM PDT Sat Aug 22 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1200 AM PDT Sat Aug 22 2026

 - Temperatures near to slightly below seasonal averages continue
   through the next week

 - Warm and dry conditions persist above 1000 feet

&&

.SHORT TERM...
Issued at 1200 AM PDT Sat Aug 22 2026
(Today and tonight)

The skies are generally clear for now with patches of stratus in
favored locations and some high level clouds continuing to stream
across the interior. Offshore, a blob of cooler air lurks offshore,
evidenced by a robust stratus deck set up off the North Bay and the
San Mateo Peninsula. Through the rest of the night, this stratus
deck is expected to expand to the coastal areas and build inland
through the post-sunrise hours when the stratus will begin to
gradually clear out.

The region remains under the influence of the balance between a
cutoff low located around 200 miles west of Cape Blanco along the
southern coast of Oregon, and an upper level ridge with an axis
extending along the crest of the Rocky Mountains. Altogether this
pattern will result in temperatures which are near to slightly below
the seasonal averages, with highs today ranging from the upper 70s
to the lower 90s in the inland valleys, the middle 90s into the
triple digits for the warmest interior spots, especially the
southern tier of Monterey County, across the 70s for areas near the
Bays, and the 60s for areas along the Pacific coast. The marine
layer remains relatively stable at around 1000-1500 feet, with warm
and dry conditions persisting above the marine layer inversion as
relative humidity values reach the 10-30% range. Winds remain
relatively light and develop in an onshore flow pattern, with wind
gusts reaching 20 to 30 miles per hour along the coast, through
favored gaps and passes, and within the northern Salinas Valley.

&&

.LONG TERM...
Issued at 1200 AM PDT Sat Aug 22 2026
(Sunday through Friday)

More of the same pattern is anticipated for the rest of the week`s
forecast, with a generally southwesterly upper level flow over the
region as the series of eastern Pacific troughs continues to balance
the ridge over the Desert Southwest. High temperatures are expected
to hover around the upper 70s to the lower 90s for the inland
valleys and the middle 60s to upper 70s near the Bays, with a subtle
drop in the temperatures in the early part of next week before the
ridge tries to build back towards the west. As noted by the previous
forecaster, a couple of broad low pressure areas to the south of
Baja California could develop into tropical systems sometime within
the 7-day outlook, and how those systems interact with the ridge is
highly uncertain at this time.

&&

.AVIATION...
(12Z TAFS)
Issued at 425 AM PDT Sat Aug 22 2026

Currently a mixed bag of LIFR-VFR with both advective and radiative
stratus out there. Moderate confidence that all terminals will
become sub-VFR this morning with a feed of stratus coming in from
the coast and radiative stratus expanding. VFR is expected by the
afternoon and may be achieved earlier than normal due to the
patchy nature of stratus. Diurnal winds will prevail. Similar
forecast on tap tonight with ceilings on the cusp of IFR/MVFR
returning late.

Vicinity of SFO...Currently VFR with westerly flow. Moderate
confidence on a ceiling developing this morning (likely on the cusp
of IFR/MVFR); this will happen either via a push of stratus from the
northwest that is 10 miles off the coast or stratus across the bay
at OAK that is expanding. Diurnal winds will prevail.

SFO Bridge Approach...The San Mateo Bridge Approach will likely stay
VFR longer than the terminal this morning; however, stratus is
surrounding it and continuing to expand.

Monterey Bay Terminals...Currently IFR with southwesterly flow at
MRY and LIFR with westerly flow at SNS. MRY is expected to further
deteriorate to LIFR with conditions improving at both terminals by
16Z. IFR stratus will stick close to the coast this afternoon
with another return to IFR conditions this evening. Diurnal winds
will prevail.

&&

.MARINE...
(Today through Thursday)
Issued at 425 AM PDT Sat Aug 22 2026

Fresh to strong northwesterly breezes will bring widespread
hazardous conditions for small craft this afternoon and evening.
Conditions will slowly improve as northwesterly breezes diminish
to become moderate to fresh Sunday and into next week. Slight to
moderate seas will prevail.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 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 3 PM this afternoon 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...DialH
LONG TERM....DialH
AVIATION...Sarment
MARINE...Sarment

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