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000
FXUS66 KMTR 231625
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
925 AM PDT Tue Apr 23 2024

...New MARINE...

.SYNOPSIS...
Issued at 304 AM PDT Tue Apr 23 2024

Cooler, unsettled conditions return today and continue throughout
late week with coastal drizzle possible this morning and again
tonight into Wednesday morning. Then, light rain possible for
Thursday night and into Friday.

&&

.UPDATE...
Issued at 904 AM PDT Tue Apr 23 2024

A healthy marine layer continues to offer almost CWA-wide stratus
that will struggle to erode through the morning. An offshore eddy
looks to continue to push stratus on land, preventing widespread
clearing until the afternoon. This delay in clearing will result
in slightly cooler highs for the areas just a bit inland from the
coast, while the more interior areas and the immediate coast`s
temperatures will stay on track from the overnight forecast.

&&

.SHORT TERM...
(Today and tonight)
Issued at 304 AM PDT Tue Apr 23 2024

Coastal drizzle is being observed across the Central Coast early
this morning and will be likely in other coastal/favored upslope
spots across the region through midmorning. Temperatures will warm
into the upper 50s to lower 60s near the coast and up to the lower
70s in the warmest interior spots. Areas where cloud cover persists
will struggle to warm out of the lower 60s.

Tonight, expect more drizzle in coastal/favored upslope spots across
the region as an upper level low approaches southern California.
Overnight temperatures will range from the mid 40s to low 50s.
Increased cloud cover will spread inland as well, similar to this
morning.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 304 AM PDT Tue Apr 23 2024

Cooler, unsettled conditions will continue Wednesday through Friday
as the aforementioned upper level disturbance moves inland.
Afternoon maximum temperatures will stay in the upper 50s to low 60s
near the coast with 60s inland. Overnight minimum temperatures will
cool into the mid 40s to low 50s with a few spots in the mountainous
terrain dropping into the low 40s.

Light rain will be possible late Thursday evening into the first
half of the day on Friday, yet rainfall amounts are expected to
remain light. Northwest winds are also forecast to increase with
gust near the coast and in the higher terrain approaching 25-45 mph
both Thursday and Friday. As a shortwave ridge builds in wake of the
exiting trough, temperatures will warm slightly to near seasonal
averages by the upcoming weekend.

&&

.AVIATION...
(12Z TAFS)
Issued at 423 AM PDT Tue Apr 23 2024

A weak low pressure system off the coast is supporting a deep
marine layer and southerly winds this morning. The deep marine
layer may even support some light coastal drizzle, though it was
removed from the TAFs due to the limited impacts and uncertain
duration. MVFR clouds are nearly blanketing the Bay Area, with a
small window of clearing over the Bay itself. Enhanced IR
satellite imagery shows that this window is closing, and all
terminals should have a ceiling by 12Z. Clouds will linger through
the day, though the ceilings will gradually lift after the sun
comes up and the winds increase a bit. Inland sites will likely go
scattered for several hours in the afternoon. Otherwise, it will
be a MVFR/VFR stratus day with moderate gusty winds out of the SW
for most sites, with some stronger gusts in the afternoon.

Vicinity of SFO...MVFR stratus has made a confident push across
the SF Peninsula overnight. These clouds will hang around all day,
but the ceiling will improve into the VFR range as the surface
temperature increases and the winds pick-up. With the low pressure
center situated just NW of SFO, SW winds will very likely be
gusty for the majority of the day. Models are in good agreement
that this system should weaken over the next 24 hours, and there
should be a return to NW flow by late Wednesday.

SFO Bridge Approach...There is a small window of clearing over the
bridge approach, though it looks to be closing soon. Otherwise, similar
to SFO.

Monterey Bay Terminals...The big surprise tonight was SNS getting
an IFR ceiling. Winds were unexpectedly calm, which allowed the
ceiling to lower and now the visibility is even starting to drop.
Southerly drainage flow should help mix that junk out before winds
flip to onshore in the late morning and become strong in the
afternoon. MRY will also get a fresh breeze this afternoon, and
may get some light drizzle here and there under a thick marine
layer.

&&

.MARINE...
(Today through Sunday)
Issued at 924 AM PDT Tue Apr 23 2024

A weak low pressure system off the coast of San Francisco will
continue to bring moderate to fresh southerly winds over the
coastal waters today. This system will gradually weaken tonight,
allowing northwest flow to return by Wednesday. Sea heights will
remain moderate through the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 9 PM PDT this evening for Pt Pinos to
     Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Flynn
MARINE...SO

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