113
FXUS66 KMTR 120454
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
954 PM PDT Wed Jun 11 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 301 PM PDT Wed Jun 11 2025

Stratus returns to portions of the Bay Area and Central Coast
overnight with coastal drizzle likely tomorrow. Breezy afternoon
onshore winds continue through the forecast period with highs
lingering in the 70s to 80s and into the 90s across the far
interior regions for much of the forecast period.

&&

.UPDATE...
Issued at 814 PM PDT Wed Jun 11 2025

Minor adjustments were made to the forecast to try and account for
cloud cover. It should still be on track to expand into the
Central Coast and Bay Area.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 301 PM PDT Wed Jun 11 2025

Stratus has mostly receded offshore except along the coastlines of
Marin and San Mateo Counties where some continues to linger. This
retreat will be fairly short lived with stratus returning to
portions of the Central Coast and Bay Area again this evening. The
marine layer looks to remain around 2000 ft again tonight which
would support stratus pushing into the Central Coast and San
Francisco Bay shoreline region. However, cloud cover is expected to
be slightly more limited tonight than it has been over the previous
days with high resolution guidance keeping the North Bay clear
tonight. One reason for this is that a weak passing shortwave trough
allowed the marine layer to deepen to around 2300 ft last night (as
seen on the 12Z OAK sounding this morning) which allowed stratus to
penetrate deep into the Bay Area. This shortwave trough has since
exited the region with more zonal flow returning as high pressure
builds over the Intermountain West. In terms of stratus clearing, it
has been trending slightly earlier in the morning each day this
week. This same trend looks to hold true tomorrow with stratus to
clear by mid to late morning across the region. This earlier
clearing of stratus will help to increase confidence that sites will
reach their forecasted high temperatures across the region. This is
unlike Monday and Tuesday where prolonged stratus coverage decreased
the amount of solar radiation able to reach the surface and kept
temperatures much cooler than originally forecast. High temperatures
on Thursday will be slightly warmer than those observed today with
highs in the upper 70s to upper 80s across the interior and in the
60s to low 70s closer to the coastline. Breezy afternoon winds
between 20 to 30 mph are expected across mountain gaps/passes and
across the higher terrain this afternoon/evening and again Thursday
afternoon/evening. Conditions are drying out across the interior
which in combination with breezy afternoon/evening winds may result
in an increased risk of grass fires - see Fires Section below -
through the weekend. &&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 301 PM PDT Wed Jun 11 2025

Things remain fairly quiet through the extended with zonal flow to
very weak ridging persisting Friday into the weekend. This will keep
the forecast across the interior fairly similar to what we have
already seen this week with highs in the 70s to low 80s and mid 60s
to low 70s along the coastline. The interior Central Coast will
remain warm through the weekend with highs in the 80s to low 90s.
The main question continues to be the progression of a weak upper
level trough (low pressure) through the Bay Area Sunday evening into
Monday. Model guidance has slowed down the troughs arrival slightly
and pushed into later into Monday with the trough exiting the region
late Monday into early Tuesday. Cluster guidance does indicate a
chance for the trough to persist through Tuesday but that scenario
seems unlikely. Temperatures will remain in the upper 70s to low 80s
across the interior on Monday before a warm up begins Tuesday with
temperatures reaching into the upper 80s to low 90s. Diurnally
breezy to gusty onshore winds continue across mountain gaps/passes,
elevated terrain, and portions of the coastline through the end of
the forecast period. Highest confidence is in gusts between 20 to 30
mph with funneling in gaps/passes potentially resulting in isolated
stronger gusts.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 301 PM PDT Wed Jun 11 2025

Things remain fairly quiet through the extended with zonal flow to
very weak ridging persisting Friday into the weekend. This will keep
the forecast across the interior fairly similar to what we have
already seen this week with highs in the 70s to low 80s and mid 60s
to low 70s along the coastline. The interior Central Coast will
remain warm through the weekend with highs in the 80s to low 90s.
The main question continues to be the progression of a weak upper
level trough (low pressure) through the Bay Area Sunday evening into
Monday. Model guidance has slowed down the troughs arrival slightly
and pushed into later into Monday with the trough exiting the region
late Monday into early Tuesday. Cluster guidance does indicate a
chance for the trough to persist through Tuesday but that scenario
seems unlikely. Temperatures will remain in the upper 70s to low 80s
across the interior on Monday before a warm up begins Tuesday with
temperatures reaching into the upper 80s to low 90s. Diurnally
breezy to gusty onshore winds continue across mountain gaps/passes,
elevated terrain, and portions of the coastline through the end of
the forecast period. Highest confidence is in gusts between 20 to 30
mph with funneling in gaps/passes potentially resulting in isolated
stronger gusts.

&&

.AVIATION...
(06Z TAFS)
Issued at 953 PM PDT Wed Jun 11 2025

Satellite imagery shows MVFR-IFR stratus building along the coast of
the San Mateo Peninsula, the East Bay Hills, and the Monterey
Peninsula. The North Bay terminals should remain clear tonight, but
the rest of the region will see stratus developing inland through
the night with moderate confidence for stratus impacts at LVK and
SJC. Stratus should dissipate through Thursday morning with
lingering patches impacting the immediate coast from Point Reyes
south through the western San Mateo Peninsula. Despite optimistic
model output showing a scattering over HAF Thursday afternoon,
confidence is still too low to include in the TAF at this point.
Breezy onshore winds will continue to diminish, remaining light
through Thursday morning before breezy onshore flow resumes Thursday
afternoon. Some LLWS is possible in the North Bay valleys and the
coastal ranges on Thursday evening as surface winds decouple from
the flow aloft.

Vicinity of SFO... MVFR-IFR ceilings through Thursday morning with a
light westerly breeze. Strong and gusty west winds resume Thursday
afternoon with a low probability (around 10-20%) for wind gusts over
35 knots. Low confidence for stratus formation Thursday night into
Friday.

SFO Bridge Approach... Lower confidence for stratus impacts to the
approach path overnight, and Thursday night into Friday, than over
the terminal. Otherwise similar to SFO.

Monterey Bay Terminals... MVFR-IFR ceilings at MRY continue through
the night before dissipating sometime Thursday morning; at SNS,
ceilings are expected to develop over the next few hours. Moderate
confidence in timing of clearing at MRY. Breezy onshore winds resume
Thursday afternoon. Low to moderate confidence (30-40% probability)
that stratus forms over MRY before the end of the TAF period, but
chances for stratus impacts increase later Thursday night.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 953 PM PDT Wed Jun 11 2025

Gusty northwest winds leading to hazardous conditions for small
craft persist through the week, with occasional gale force gusts
developing near Point Reyes and south of Point Sur. Moderate to
rough seas will prevail through the week.

&&

.FIRE WEATHER...
Issued at 301 PM PDT Wed Jun 11 2025

While the marine layer will remain in some capacity over the next
few days, what happens above the marine layer is more of a fire
weather concern.  The last night or two have featured moderate to
poor recoveries above the marine layer and that will continue
Thursday night and Friday.  In fact, some locations are hitting
single digit and lower teens for RH values. Hi-res models even
indicate a burst of NE flow late tonight into early Thursday over
the N Bay. Not overly strong, but this will further enhance any
drying. There is some quote, recovery, during the daytime, but
another factor comes in. The breezy onshore flow. Winds will
remain breezy each afternoon/evening through the Delta, and any
inland gap or pass. The combination of dry fine fuels (grasses),
lower RH, breezy winds with gusts in the 20-40 mph will elevate
fire weather concerns.

&&

.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 AM PDT Friday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

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

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...DialH
MARINE...DialH

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