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000
FXUS66 KMTR 210550
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1050 PM PDT Sat Apr 20 2024

...New AVIATION...

.SYNOPSIS...
Issued at 247 AM PDT Sat Apr 20 2024

Slight warming trend across the interior through Monday with
diminishing marine influences near the coast. Potential
drizzle/light rain chances mid-to-late next week.

&&

.UPDATE...
Issued at 904 PM PDT Sat Apr 20 2024

Clear and quiet across the region this evening outside of some
passing high clouds. Modest winds aloft have dissipated the
earlier low stratus along the coast, and it should remain well
offshore a bit. However expect low-level northwest flow to
promote renewed stratus intrusion around the Monterey Bay later
tonight into Sunday morning. The going forecast is in good shape
with no update necessary.

&&

.SHORT TERM...
(This evening through Sunday)
Issued at 131 PM PDT Sat Apr 20 2024

After a summerlike start to the day with low clouds the afternoon
features wall to wall sunshine across the Bay Area and Central
Coast. Ample sunshine, building 500mb heights, and a warming
airmass all contributed to warmer temperatures this afternoon.
Latest 24 hour trend shows many locations running 2 to 5 degrees
warmer than yesterday. The warmest interior locations have a
20-30% chc of actually breaking 85 degrees.

Tonight and Sunday: Expecting less cloud cover thanks weak
offshore flow develop at 2500 feet. Not strong offshore flow by
any means, but a dry flow patter leading to better low level
mixing and less stratus. That begin said, hi-res ensemble
guidance does indicate some patchy stratus piling up around the
Monterey peninsula and locally inland. This seems most plausible.
Given less morning clouds, even higher 500mb heights (building
high pressure), and warming airmass (warmer 850mb temps) Sunday
will feature even warmer temperatures. Max temps on Sunday will
range from low 60s to low 70s coast/bays and 70s to mid 80s
interior. Heat Risk potential still remains in the minor category.

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 150 PM PDT Sat Apr 20 2024

To begin the workweek only subtle changes are expected with
regards to sensible weather. Onshore flow at the sfc will keep
cool temperatures at the coast, but interior locations will see
another day of mild temperatures.

Tuesday and beyond: High pressure weakens and is slowly replaced
by a weak upper level low off the coast on Tuesday. This feature
will ultimately weaken and move inland as an open wave on
Wednesday. This change in the longwave pattern will bring
temperatures to below seasonal averages for Tuesday and Wednesday
with max temps staying mainly in the 60s. There`s also a 10-20%
chc of some patchy drizzle Wednesday morning. Cool weather, but
dry, remains for Thursday. Light rain and/or drizzle returns to
the forecast Thursday night and Friday as a more defined upper
level trough sweeps through the region. In addition, more clouds
are expected with a colder airmass. Temperatures on Friday will
struggle to reach 60 at the coast and the hills with interior
locations staying in the 60s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1049 PM PDT Sat Apr 20 2024


VFR through the TAF period for most terminals. Moderate onshore
winds from earlier this evening have helped to mix out much of the
stratus. As a result, not expecting stratus to impact terminals
tonight with the exception of Monterey Bay briefly. Otherwise, light
winds persist overnight and increase into the afternoon tomorrow to
become breezy. Stratus does not appear to return until well beyond
the TAF period.


Vicinity of SFO...VFR. A FEW low clouds may drift over the
terminal in the early morning of Sunday, but not expecting CIGs to
form. Winds are still elevated at this hour, and are expected to
remain so through much of the night, easing only to about 10
knots. In the afternoon of Sunday, moderate winds return, but are
not expected to gust above 20 knots or so. Winds then ease into
the evening hours of Sunday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus may make a brief appearance over
the KMRY terminal in the early to mid morning of Sunday, bringing
MVFR conditions. Aside from this, expecting VFR from the late
morning onwards. Onshore winds return in the afternoon around 10-12
knots.

&&

.MARINE...
(Tonight through next Friday)
Issued at 904 PM PDT Sat Apr 20 2024

Fresh to strong northerly winds continue to build across the
coastal  waters with near gale force gusts possible through early
Monday  morning. Gale force gusts are expected over the far
northern outer  waters in this same time period, but begin to
diminish late Sunday  night. Isolated gale force gusts remain
possible across the far  southern outer waters through Sunday
night. Northwest swell builds  through Monday as gusty conditions
continue but looks to diminish by  the middle of next week. Light
southerly swell continues to move  through the waters this weekend
and through the upcoming work week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT Sunday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 3 AM PDT Monday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 AM PDT Sunday for Pt Arena to Pt
     Reyes 10-60 NM.

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

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...AC
MARINE...SPM

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