Atherton, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

349
FXUS66 KMTR 230002
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
502 PM PDT Sun Jun 22 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 131 PM PDT Sun Jun 22 2025

Quiet weather on tap for the upcoming week, with the return of
coastal clouds and potential for overnight fog. Temperatures
gradually return to near seasonal averages, especially for inland
areas.

&&

.SHORT TERM...
(This evening through Monday)
Issued at 131 PM PDT Sun Jun 22 2025

A quiet weather pattern prevails over the region this afternoon as
an upper level trough remains placed over the Intermountain West.
This feature will continue to shift to the north-northeast with a
secondary low developing over northern California. However, the main
driver of our weather will be the high pressure over the eastern
Pacific with a gradual warming trend to more near seasonable norms
on Monday. This should bring a deepening marine layer now at around
500 feet in depth to around 1,000 feet by tonight. The question
remains, how much coastal stratus develops (none currently within
100-150 miles of the coast via satellite imagery). The HRRR
indicates the best chance for stratus to be along the San Francisco
Peninsula and the Monterey Bay region late tonight and early Monday
morning.

&&

.LONG TERM...
(Monday night through next Saturday)
Issued at 131 PM PDT Sun Jun 22 2025

Tuesday and beyond, ensemble and cluster analysis indicate a high
probability for troughing to quasi-zonal flow across the region.
This will allow for a modest marine layer to be in place throughout
the week with late night and early morning stratus and/or patchy fog
to penetrate inland into the coastal adjacent valleys. Any low
clouds that do develop will mix out each afternoon and giving way to
mostly sunny sky conditions. Onshore flow also is expected throughout
the week with an increase in winds during the afternoon and early
evening hours.

&&

.AVIATION...
(00Z TAFS)
Issued at 502 PM PDT Sun Jun 22 2025

Cloud cover is beginning to build along the coast with MVFR CIGs
affecting HAF and MRY. These CIGs look to reach SNS in the late
evening and all terminals affect by CIGs will see them fall to IFR
levels overnight. Moderate to breezy winds last through much of the
evening before reducing into the night. Expect mostly light to
moderate winds through the late morning and early afternoon on
Monday. CIGs at MRY and SNS look to have some moments of clearing
overnight from an eddy in the Monterey Bay, but CIGs look to mostly
prevail until the mid to late morning before eroding and getting
back to VFR. HAF looks to keep CIGs through the TAF period. Expect
another round of moderate to breezy winds again for Monday
afternoon that will linger into that evening. Monday evening and
overnight shows strong potential for a stronger marine stratus push,
leading to more TAF sites seeing IFR CIGs for that night.


Vicinity of SFO...VFR last through Monday evening. Breezy winds last
into the early night before gusts cut off and winds become moderate.
Expect a few moments of thin clouds to move through the San Bruno
Gap overnight, but not enough to fill over the terminal. Breezy
winds return Monday afternoon and last into that evening before
becoming light as IFR CIGs build.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Moments of MVFR CIGs affecting MRY become
more consistent into the mid evening and fill over SNS slightly
later in the evening as winds reduce. CIGs lower to IFR levels into
the night. An otter eddy forms in the middle of the Monterey Bay
overnight, which could lead to pulling and pushing of CIGs and
fairly short periods of scattering/clearing over the terminals. VFR
conditions return in the mid to late morning as CIGs erode and winds
become more moderate.


&&

.MARINE...
(Tonight through next Saturday)
Issued at 502 PM PDT Sun Jun 22 2025

Widespread hazardous marine conditions continue for the waters
with strong northwest breezes, near-gale to gale force gusts, and
rough seas. Conditions will improve on Monday, but northwest
breezes remain fresh to strong and seas remain moderate to rough
through Thursday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until midnight PDT tonight for CAZ006-506-
     508.

PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay.

     Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt
     Reyes 0-10 nm.

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

     Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory until 9 AM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Murdock
MARINE...DialH

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