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000
FXUS66 KMTR 202056
AFDMTR

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

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

.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.

&&

.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...
(18Z TAFS)
Issued at 1050 AM PDT Sat Apr 20 2024

Stratus has dissipated for most stations with only SNS reporting non-
VFR conditions still. Satellite shows stratus dissipating over SNS
with clearing expected by 1830Z at the latest. Confidence in stratus
returning tonight remains low. Moderate winds and lower RH values
will both be limiting factors for stratus development. Currently
expecting MVFR CIGs at OAK, MRY, and SNS overnight due to lighter
wind speeds and slightly higher RH values. Low confidence but
guidance does suggest LIFR may be possible for MRY and SNS during
the early morning hours. Moderate westerly to northwesterly winds
expected during the day with lighter, more variable winds expected
overnight.

Vicinity of SFO...VFR through the TAF period with gusty winds
possible this afternoon. Guidance hints that MVFR CIGs may become
more likely overnight but moderate westerly winds will help keep the
atmosphere more well mixed and inhibit stratus development. Winds
will weaken slightly during the late morning before moderate
westerly winds return mid afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR transitioning to MVFR overnight. CIGs
continue to linger at SNS with satellite showing full dissipation
should occur within the next 30-45 minutes. Low to moderate
confidence that stratus will develop overnight. By early morning,
breezy westerly to northwesterly winds weaken slightly but RH values
are relatively high (80-90%) giving a little more confidence to
include BKN MVFR CIGs. Similar to today, stratus will dissipate
towards the end of the TAF period in the late morning.

&&

.MARINE...
(Today through Thursday)
Issued at 1050 AM PDT Sat Apr 20 2024

Northerly winds build into the afternoon today to become fresh to
strong across much of the waters through early Monday morning with
near gale force gusts possible. Gale force gusts are expected
over the far northern outer waters in this same time period, but
begin to diminish late Sunday night. Northwest swell builds Sunday
as gusty conditions continue but looks to diminish towards the
middle part of the 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 this evening for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 PM PDT Sunday for Pt Arena to Pt
     Reyes 0-10 nm-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.

     Small Craft Advisory until 9 PM PDT Sunday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...Kennedy
MARINE...Kennedy

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