294
FXUS66 KMTR 131813
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1113 AM PDT Thu Jun 13 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 247 AM PDT Thu Jun 13 2024

Quiet through the rest of the week with slight warm up on Friday
across the interior. Near normal temperatures by the weekend.
Increasing confidence for high wind potential and increased fire
danger Sunday into early next week.

&&

.SHORT TERM...
(Today through Friday)
Issued at 247 AM PDT Thu Jun 13 2024

Temperatures this afternoon will be similar to those yesterday as
zonal flow conditions north of the region while an upper level low
remains parked off of southern California. Temperatures this
afternoon will range from the upper 50`s to 60`s near the coast and
bayshore, 70`s to near 80 degrees just inland and into the East Bay,
Santa Clara Valley, and southern Salinas Valley. The regions
farthest interior will reach into the upper 80`s to low 90`s.

Tonight, expecting less widespread stratus to penetrate inland as
the marine layer begins to compress. Overnight low temperatures are
forecast to be in the upper 40`s across the North Bay and San
Francisco Peninsula with low/mid 50`s elsewhere.

Friday will be slightly warmer in response to increased sunshine,
northerly winds, and weak ridging aloft. Coastal/bayshore areas will
remain cool but the interior will see more upper 80`s to low 90`s.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 247 AM PDT Thu Jun 13 2024

Heading into the weekend will be relatively quiet as temps cool a
bit again down to around seasonal normals. The real story will be
later in the weekend and into early next week. A deep upper low
currently up in the Gulf of Alaska becomes dislodged and moves
into the Pacific Northwest, kicking off another deep disturbance
sliding into the West Coast/Great Basin. Well advertised by
ensemble cluster analysis, there is high confidence in this
pattern change taking place Sunday into Tuesday. Placement of the
upper level trough axis is key when determining where the
strongest winds will be and their direction. There is higher
confidence that the strongest winds will remain over the waters
and near coastal areas, including more inland coastal gaps such as
the Petaluma Gap, San Bruno Gap, and other NW-SE oriented valleys.
While we aren`t expecting any widespread offshore winds as of this
forecast, the positioning of the trough will ultimately be the
deciding factor, so stay tuned to future updates as confidence
gradually increases. With grasses and fine fuels drying out
rapidly, it looks like the Sunday-Monday timeframe is one to watch
when it comes to elevated fire danger, particularly in the North
Bay where fine fuels are drier than elsewhere around the Bay Area
and Central Coast. For now, moisture recovery looks decent going
into the weekend as winds should remain onshore, but we are
keeping a close eye on the positioning of the trough and will
update messaging accordingly.

&&

.AVIATION...
(18Z TAFS)
Issued at 1113 AM PDT Thu Jun 13 2024

Stratus coverage continues over MRY and SNS while satellite shows
stratus coverage dissipating over STS, APC, and OAK. The marine
layer is expected to compress tonight with less widespread stratus
than last night. Current thinking is that stratus will generally
stick closer to the coast and SF bay. Low confidence that stratus
will reach STS and APC but models indicate some lower level clouds
may be possible. Forecast vertical wind profiles show RH values
generally 50 to 60 percent so leaning towards the side that any
clouds that do develop will be on the FEW to SCT side. Light to
moderate west to northwesterly winds continue through the afternoon
with gustier conditions returning through the afternoon into the
evening. Light west to southwesterly winds return overnight for most
sites before moderate winds return after the end of this TAF period.

Vicinity of SFO...Moderate west to west-northwest winds continue
through the afternoon before lighter westerly winds return
overnight. Some uncertainty remains in wind direction but models are
in higher agreement that winds stay more W to NW. Moderate
confidence that MVFR conditions will return overnight with low
confidence that a more compressed marine layer will push ceiling
heights down into IFR territory.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently MVFR at MRY and SNS. Moderate
confidence that ceilings at MRY will not clear as satellite shows a
thicker layer of clouds over the area. Clearing at SNS is a little
more uncertain with models split on if ceilings will clear this
afternoon. Based on satellite trends showing stratus dissipating in
the vicinity of SNS - leaning towards stratus clearing for at least
a few hours this afternoon. Stratus will return early this evening
at SNS with MVFR to IFR CIGs expected overnight. Winds will
generally stay west to northwest with strong, gustier winds expected
during the afternoon and early evening.

&&

.MARINE...
(Today through Tuesday)
Issued at 1113 AM PDT Thu Jun 13 2024

A small craft advisory has been issued for the San Francisco Bay
north of the Bay Bridge through the San Pablo Bay, Suisun Bay, and
the West Delta for gusts up to 25 knots. Fresh to strong
northwesterly winds continue over the northern waters through the
end of the week with strong to near gale force gusts possible by
Friday. Heading into the weekend, strong north to northwesterly
winds will spread southwards over much of the coastal waters with
gale-force winds increasing in likelihood. Significant wave
heights up to around 12 to 15 feet in the outer waters and 10 to
13 feet in the inner waters continues into the weekend.

&&

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

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

&&

$$

SHORT TERM...RGass
LONG TERM....Behringer
AVIATION...Kennedy
MARINE...Kennedy

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