639
FXUS66 KMTR 151008
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
308 AM PDT Sun Sep 15 2024

...New SYNOPSIS, SHORT TERM, LONG TERM...

.SYNOPSIS...
Issued at 203 AM PDT Sun Sep 15 2024

Gusty winds and cooler temperatures today as a potent upper low
digs into the west coast. Below normal temperatures last through
mid week with a second upper low moving in. Gradual warmup into
next weekend.

&&

.SHORT TERM...
(Today and Monday)
Issued at 203 AM PDT Sun Sep 15 2024

Hints of the approaching system beginning to show up this morning
in the form of gusty winds and very light, isolated showers. As of
writing, the initial cold front is located over Mendocino county,
and will continue to move southward through the Bay Area by about
midday today. There is some evidence of light showers with rain
making it to the ground as some Alert CA cams in Mendocino county
show a few drops on the lenses. Current thinking for rainfall
across the Bay Area hasn`t changed much. Still on the order of a
few hundredths to a tenth or so for those that are lucky enough to
see rain (generally coastal and terrain enhanced areas). Winds
will continue to increase through the day today, and should peak
by late tonight/early Monday morning as the trough axis swings
inland. Most areas will likely see gusty winds to an extent
through this afternoon and evening, but the strongest winds will
be in the favored NW flow coastal areas (e.g. Sonoma coast, Golden
Gate, and Santa Cruz Co coast west of Capitola) and NW/SE
oriented valleys and gaps (e.g. Salinas Valley, East Bay Valleys,
and the San Bruno Gap near SFO). Will other locations generally
see 25-30 mph winds, these favored areas have to potential to see
35-40 mph, with occasional gusts of 45-50 mph. We are holding off
on a Wind Advisory on this shift since we will only touch the
lower criteria in a few isolated areas for a relatively short
period of time. Winds begin to diminish early Monday morning, and
will give way to what should be a very pleasant, cool day across
much of the region with highs ranging from the upper 50s to
mid-70s.

&&

.LONG TERM...
(Tuesday through Saturday)
Issued at 203 AM PDT Sun Sep 15 2024

By midweek, we could be looking at a deja vu situation, but with
slightly less wind. Another cold-core system is poised to slide
down the west coast and basically follow in the footsteps of the
system that is moving in today (as far as we`re concerned for our
region). A bit less dynamic in the upper levels, we wouldn`t
expect as much wind from the midweek system, but we do have
another shot for some light rainfall Wednesday. Still nothing
astonishing as far as rainfall totals go. Perhaps a few hundredths
here and there. Nevertheless, great for putting a slight damper on
our local fire season. After the Wednesday system departs, the
pattern begins a swing back towards slight ridging with
temperatures increasing to around normal by the weekend.

&&

.AVIATION...
(06Z TAFS)
Issued at 1135 PM PDT Sat Sep 14 2024

Stratus has pushed inland over the Monterey Bay and SF Bay
terminals, bringing predominantly IFR/LIFR CIGs. Winds are currently
light for most terminals, but are expected to steadily increase
throughout the nighttime as a cold front approaches. CIGs are likely
to last through the early afternoon of Sunday, only clearing to VFR
briefly before returning to MVFR CIGs in the evening of Sunday.
Winds Sunday afternoon will be moderate and gusty out of the W/NW
generally, and are not likely to ease until beyond the current TAF
period. Towards the end of the TAF period, chances of light rain
begin to arrive for area terminals.

Vicinity of SFO...Current MVFR CIGs are expected to lower to become
borderline IFR overnight tonight. Winds although currently light
will increase out of the W to become moderate and gusty. CIGs last
through the late morning of Sunday, but will rise to become MVFR
again after sunrise as diurnal heating begins. When CIGs clear in
the late morning to early afternoon of Sunday, VFR conditions will
return, accompanied by strong winds and gusts nearing 35+ kts.
MVFR CIGs will return again in the evening, though winds will
continue to gust strong.

SFO Bridge Approach...Low coastal clouds are likely to filter into
the SF Bay overnight bringing low CIGs.

Monterey Bay Terminals...LIFR CIGs persist through the late morning
Sunday. Winds will begin to increase in the late morning of Sunday.
At this time, not expecting CIGs to clear on Sunday, but have high
confidence in CIGs rising to become IFR, then MVFR in the afternoon.
Moderate W/NW winds will steadily increase through the morning and
afternoon, with gusts near 15-20 kts likely for area terminals.

&&

.MARINE...
(Tonight through next Friday)
Issued at 1135 PM PDT Sat Sep 14 2024

A series of early season cold fronts will move through the
coastal waters this week with a persistent strong NW breeze and
near gale force gusts. Seas will remain rough outside of protected
waters through the forecast period. There a chance for
thunderstorms Monday and Wednesday, which would produce locally
stronger winds.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Monday for SF Bay N of Bay
     Bridge.

     Small Craft Advisory from 9 AM this morning to 3 AM PDT Monday
     for Mry Bay-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena
     to Pt Reyes 0-10 nm.

     Gale Warning from 3 PM this afternoon to 3 AM PDT Monday for Pt
     Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 AM PDT Monday for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 AM this morning to 9 AM PDT Monday
     for Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 9 PM PDT this evening for Pt Arena to
     Pt Reyes 10-60 NM.

     Gale Warning from 9 PM this evening to 3 AM PDT Monday for Pt
     Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 PM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...AC
MARINE...Flynn

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