-- Discussion containing changed information from previous version are highlighted. --
838
FXUS66 KMTR 231114
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
414 AM PDT Thu May 23 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 1225 PM PDT Wed May 22 2024

Summer-like pattern to persist through Thursday. Temperatures are
forecast to dip below seasonal averages this weekend as an upper
level trough impacts the region. Temperatures begin to warm Sunday
through the next week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 250 AM PDT Thu May 23 2024

Patchy stratus is currently located along the Santa Cruz coastline
and extending into portions of Monterey, San Benito, and Santa Clara
counties. Stratus coverage may extend a bit farther into Monterey
Bay and up the San Mateo coastline but is not expected to expand too
far inland. The Fort Ord Profiler shows the top of the marine layer
around 1600-1800 feet which is fairly comparable to the depth of the
marine layer yesterday. Given persistence, this helps increase
confidence that any stratus that develops will stay along the
coastline and portions of the Monterey Bay. Overcast conditions are
expected to clear out by late morning/early afternoon with some
potential for scattered clouds to persist throughout the remainder
of the day. Widespread stratus coverage will return fairly early in
the evening throughout much of the Bay Area and Central Coast as
onshore flow increases and a weak surface low pressure system
approaches the coast.

As broad upper level troughing continues and offshore
flow weakens, temperatures will continue to cool Thursday with high
temperatures on average 1 to 3 degrees cooler than those observed on
Wednesday. Across the interior, temperatures will be seasonal with
highs generally in the 70s to low 80s but, along the coast, below
average temperatures in the mid 50s to low 60s persist. Minor heat
risk continues for portions of the Bay Area and Salinas Valley.
Individuals who are extremely sensitive to heat should remember to
stay hydrated while outdoors and to take breaks as needed. Slightly
drier RH values persist inland during the day on Thursday before
higher RH values and increased moisture return inland with this next
weak system.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 250 AM PDT Thu May 23 2024

A weak low pressure system will move inland Friday into Saturday and
bring widespread below average temperatures, increased stratus
coverage, and some potential for light drizzle in coastal areas.
Most inland locations will see temperatures 5 to 10 degrees below
average but some may see more significant drops with high
temperatures 10 to 15 degrees below average. High temperatures
throughout the interior will be in the 60s with a few areas of
elevated terrain potentially reaching the low 70s. Meanwhile on the
coast, temperatures will struggle to make it out of the upper 50s
and into the lower 60s Friday and Saturday. Ensemble and hi-res
guidance continue to suggest light drizzle, particularly in the
Monterey Bay region, is likely along the coast with non-impactful
accumulations typically less than 0.1". By Monday, shortwave ridging
will build over the West Coast with inland temperatures warming into
the upper 70s to low 80s and coastal temperatures into the upper 50s
to mid 60s.

If you are not a fan of the cooler weather we have been having, you
are in luck! Updated CPC graphics show above average temperatures
will become increasingly likely by early June. During this same time
frame, long term guidance is showing upper level ridging building
and, for the most part, lingering over the West Coast. Given that
this scenario is still a ways out, we will have to wait and see how
guidance continues to trend and how the forecast evolves.

&&

.AVIATION...
-- Changed Discussion --
(12Z TAFS)
Issued at 410 AM PDT Thu May 23 2024

VFR through today except around Monterey Bay, where MVFR stratus
will persist into the morning to afternoon hours. Stratus returns
tonight with greater coverage around portions of the greater Bay
Area. Light surface winds along with strong northerly winds aloft
will lead to LLWS concerns at KAPC this morning.

Vicinity of SFO...Generally clear but with at least SCT low
stratus in the vicinity by late tonight. Most likely outcome is
VFR through the TAF period, but at least a low potential for MVFR
ceilings to reach the terminal towards the mid morning hours on
Friday. This will be fine tuned with future updates. The other
issue is gusty onshore winds which will develop for this afternoon
into this evening. High confidence in gusts reaching 30 kt
around/after 22Z and likely to remain there through 06/07Z. Low
confidence in exceeding Airport Weather Warning criteria of 35 kt
but this will be monitored.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...Low stratus is patchy early this morning
and may come and go at the terminals through late morning with
MVFR to periodically VFR conditions. Stratus will clear towards
the coast this afternoon, with low confidence in whether KMRY will
scatter out or remain in MVFR. For now the TAF calls for a period
of partial afternoon clearing, but adjustments based on trends may
be necessary. MVFR ceilings will expand overnight into Friday with
cool and breezy onshore winds persisting.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
(Today through Tuesday)
Issued at 410 AM PDT Thu May 23 2024

Building high pressure over the Eastern Pacific will allow strong
northwesterly winds to prevail today, with gale force gusts
across the outer waters. Expect hazardous conditions and steeper
wind waves as a result. Winds diminish somewhat heading into the
weekend as high pressure weakens and a troughing pattern evolves.
However breezy to gusty conditions should persist in the outer
waters heading into early next week.
-- End Changed Discussion --

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Gale Warning until 9 AM PDT this morning for Pt Arena to Pt
     Reyes 0-10 nm.

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

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

     Gale Warning until 3 AM PDT Friday for Pt Arena to Pt Reyes 10-
     60 NM.

     Gale Warning until 9 PM PDT this evening for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...SPM
MARINE...SPM

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