-- Discussion containing changed information from previous version are highlighted. --
717
FXUS66 KMTR 130405
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
905 PM PDT Wed Jun 12 2024

...New UPDATE...

.SYNOPSIS...
Issued at 1234 PM PDT Wed Jun 12 2024

Quiet through the rest of the week. Near normal temps by the
weekend. Increasing confidence for high wind potential and
increased fire danger Sunday into early next week.

&&

.UPDATE...
-- Changed Discussion --
Issued at 856 PM PDT Wed Jun 12 2024

No changes to the forecast were require attm. Temperatures
will return to near normal for the end of the week through
the weekend. Gusty west/northwest surface winds will spread
across our area over the weekend into the beginning of next
week, with elevated fire weather concerns likely following
suit.
-- End Changed Discussion --

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 1234 PM PDT Wed Jun 12 2024

Noticeably cooler temps today across the area as the upper level
ridge moves out and the marine layer deepens in response to a weak
mid level shortwave trough. Additionally, more robust marine
stratus associated with moisture from a weak disturbance off the
coast of southern CA will continue to linger for areas from around
Santa Cruz to the Big Sur coast. A few degrees warmer for
Thursday as the shortwave kicks out. Overall not much in the way
of impactful changes in the short term. Pleasant day ahead on
Thursday with little in the way of heat risk.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 1234 PM PDT Wed Jun 12 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...
(00Z TAFS)
Issued at 434 PM PDT Wed Jun 12 2024

MVFR stratus continues at the immediate coast south of the Golden
Gate and throughout the Monterey Bay region. Breezy onshore winds
with a southerly component are developing across the region and will
diminish in the evening. MVFR-IFR stratus builds back at the coast
and the Salinas Valley overnight. Some models show stratus flowing
through the Golden Gate tonight, but probabilities are low and the
TAFs remain VFR. Ceilings lift through Thursday morning and onshore
winds return in the afternoon.

Vicinity of SFO... Model guidance suggests a low confidence for IFR-
MVFR ceilings at the terminal late tonight, and returning later
Thursday evening, but with low probabilities (at most 10-20%) the
TAFs remain VFR throughout. Southerly winds are beginning to
strengthen and will gust to around 20-25 knots. Winds diminish
overnight and turn towards the northwest on Thursday, gusting to
around 15-20 knots.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... The terminals remain at MVFR through the
day, with ceilings falling to IFR overnight. Breezy onshore winds
gusting to around 20 knots continuing through the evening when winds
diminish, before returning Thursday afternoon. A moderate confidence
(60-70% probability) that VFR returns late Thursday morning, with a
potential for an early return for stratus at MRY just before the end
of the TAF period.

&&

.MARINE...
(Tonight through next Monday)
Issued at 434 PM PDT Wed Jun 12 2024

Northwesterly winds persist over the northern waters through the
end of the week with gale force gusts possible over the northern
waters through early Thursday. Widespread strong northwesterly
winds with gale force gusts will build by the weekend and
continue into next week. Significant wave heights up to around 12
to 15 feet in the outer waters continue into the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Thursday for Pt Arena to Pt
     Reyes 0-10 nm.

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

     Gale Warning until 9 AM PDT Thursday for Pt Arena to Pt Reyes 10-
     60 NM.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...DialH
MARINE...DialH

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