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000
FXUS66 KMTR 210407
AFDMTR

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

...New UPDATE, MARINE...

.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...
(00Z TAFS)
Issued at 428 PM PDT Sat Apr 20 2024

Satellite shows clear skies across the region. VFR will prevail
through the TAF period for most terminals except Monterey Bay
terminals where there is moderate confidence that MVFR ceilings will
develop late tonight/early Sunday morning. Models suggest North Bay
develop MVFR/IFR conditions near 15Z but had low confidence to
include in TAFs at this moment. Moderate to breezy
northwesterly/westerly winds will diminish tonight and become
variable and will start to rebuild near the late morning.

Vicinity of SFO...VFR through the TAF period with gusty
northwesterly winds. Winds will diminish over night before becoming
breezy Sunday afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR with moderate northwesterly winds.
Expect MVFR conditions late tonight into the early morning hours
before VFR prevails after 17-18Z. Winds will diminish overnight
before becoming moderate to breezy by Sunday afternoon.

&&

.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.

&&

$$

UPDATE...SPM
SHORT TERM...MM
LONG TERM....MM
AVIATION...SO
MARINE...SPM

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