-- Discussion containing changed information from previous version are highlighted. --
696
FXUS66 KMTR 242120
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
220 PM PDT Fri May 24 2024

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

.SYNOPSIS...
Issued at 1231 AM PDT Fri May 24 2024

Cool temperatures this weekend with a slight warm up slated for
next week. Quiet, summer-like pattern persists through the period.

&&

.SHORT TERM...
-- Changed Discussion --
Issued at 205 PM PDT Fri May 24 2024 (This evening through
Saturday)

As we head into the un-official kick off to summer this weekend it
doesn`t really feel like summer. The latest 24 hour trends
indicate many locations running 5 to 10 degrees colder today than
Thursday. Why the big change? The longwave pattern changed thanks
to a passing upper level trough and a weak surface front. This
trough and colder air aloft help to increase onshore flow too.
SFO-SAC gradient is pushing 3.3mb this afternoon, which is also
stronger than yesterday. The increased onshore flow has also kept
the marine stratus lingering well into the afternoon. Pretty
impressive when one looks at the visible satellite and still sees
clouds spreading across the SF Peninsula and into the East Bay
Hills. Needless to say, temperatures were nudged downward today
around SF Bay due to lingering clouds. One final note with
today`s onshore flow, peak gusts of 45-50 mph have been observed
in the East Bay Hills.

Tonight through Saturday: Onshore flow will ease overnight, but
still remain onshore. Given persistent onshore flow will expect
another night of widespread stratus moving inland. Have added
patchy fog and drizzle to the coast/favored upslope areas. After a
cloudy start to the day on Saturday some clearing will be had, but
stratus will lingering around Monterey Bay and SF Peninsula.
Another cool day with max temps in the upper 50s/60s coast and
60s/70s inland. Forecast onshore gradients will be close 3mb again
so gusty winds in the afternoon seem plausible.
-- End Changed Discussion --

&&

.LONG TERM...
-- Changed Discussion --
Issued at 217 PM PDT Fri May 24 2024 (Saturday night through next
Thursday)

Slight shift in the upper level pattern for the rest of the
weekend through Memorial Day will lead to a gradual warm up
through next week. 500 mb heights will increase with warming 850
mb temps all yielding warmer temperatures. Closer to seasonal
averages by the end of next week as far interior locations
approach 90 degrees. Night and morning clouds clearing back to
the coast each afternoon will also continue.
-- End Changed Discussion --


&&

.AVIATION...
-- Changed Discussion --
(18Z TAFS)
Issued at 205 PM PDT Fri May 24 2024

Update: Continuing satellite observations of stratus flows into
the SF Bay and Monterey Bay regions have further decreased
confidence in stratus clearing at those locations. The TAFs for
SFO, OAK, MRY, and SNS have all been amended to retain MVFR
ceilings through the day. The previous discussion below has been
edited to reflect the updated forecast.

Satellite imagery shows MVFR stratus clearing out across the SF Bay
Area and Monterey Bay region, expected to continue through the
early afternoon. Breezy and sometimes gusty northwest winds will
develop this afternoon, with gusts up to around 20 to 25 knots.
High confidence for at least MVFR stratus coming into the
terminals through the evening and overnight hours, except for the
North Bay terminals where confidence is moderate. IFR to LIFR
stratus will develop later on in the night along the coast, and
into the SF Bay terminals and near Monterey Bay.

Vicinity of SFO... MVFR stratus clearing by the afternoon. Strong
west winds will develop through the day with sustained winds near
20 knots and gusts around 30 knots. At this time, low confidence
that winds will gust above 35 knots. Will monitor evolution of
winds throughout the day and will amend TAF if necessary. High
confidence of MVFR or marginal IFR stratus coming into the
terminal area tonight, clearing late Saturday morning with
similarly strong, but not as gusty, west winds Saturday afternoon.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR stratus expected to clear out later
this morning. Breezy northwest winds gusting to 20-25 knots will
develop this afternoon. MVFR stratus will return this evening, with
a high confidence of ceilings descending to IFR-LIFR through the
night into early Saturday morning. Clearing is not expected until
after the end of the TAF period.
-- End Changed Discussion --

&&

.MARINE...
(Today through Wednesday)
Issued at 911 AM PDT Fri May 24 2024

A weakening pressure gradient will allow for strong northwesterly
breezes to ever so slightly diminish and significant wave heights
to abate going into the weekend; however, hazardous conditions and
steeper wind waves will still be prevalent across the waters. As
surface high pressure over the Eastern Pacific Ocean builds and
moves east by mid-week, northwesterly breezes will increase and
significant wave heights will build.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for SF Bay N of
     Bay Bridge.

     Small Craft Advisory until 9 PM PDT this evening for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60
     NM.

     Small Craft Advisory from 3 PM to 9 PM PDT Saturday for Mry Bay.

     Small Craft Advisory until 3 AM PDT Sunday for Pt Arena to Pt
     Reyes 0-10 nm.

     Small Craft Advisory until 9 AM PDT Saturday for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory from 3 PM Saturday to 3 AM PDT Sunday for
     Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras
     Blancas 0-10 nm.

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

     Small Craft Advisory until 9 AM PDT Sunday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory from 3 PM Saturday to 9 AM PDT Sunday for
     Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...DialH
MARINE...DialH

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