431
FXUS66 KMTR 160540
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1040 PM PDT Wed May 15 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 1232 PM PDT Wed May 15 2024

Quiet weather will continue with a persistent marine layer through
the forecast period. Morning clouds and mist will clear in the
afternoon. Despite the clearing, coastal areas will remain in the
cool marine air, keeping highs in the 60s. Inland and high
elevation areas will reach the 70s and 80s each afternoon.

&&

.UPDATE...
Issued at 903 PM PDT Wed May 15 2024

Low level marine stratus this evening has begun filling farther
inland as expected and will persist through the overnight hours,
with patchy fog and periods of drizzle as well. Early morning low
temperatures will remain similar to the past few days, dropping
into the upper 40s to mid 50s area wide. Highs tomorrow will once
again be in the low 60`s near the coast, then into the 70`s and
80`s the farther you go inland during the afternoon. Onshore flow
will result in breezy winds across some of the gaps and passes,
especially the Salinas Valley where gusts are expected to reach
30 MPH at times in the afternoon.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 1232 PM PDT Wed May 15 2024

The stratus is clearing on schedule and should return this
evening. The marine layer is currently around 1500-2000 ft deep
as identified by a sharp low level inversion on the 12Z sounding
and current observations from area profilers. NAM point soundings
suggests the marine layer will compress to around 800 ft over the
next 18 hours. This will cause a lower cloud deck Thursday, with
more areas impacted by mist and fog. It will also limit the extent
of the marine layer, keeping more inland areas in the sun and the
warmer continental air mass. Otherwise, the weather pattern is
pretty stable with mild temperatures and a weak pressure gradient
producing light to gentle winds.

&&

.LONG TERM...
(Thursday night through next Thursday)
Issued at 1232 PM PDT Wed May 15 2024

The current pattern will remain fairly stable through Sunday. Low
clouds in the morning along the coast and adjacent valleys will
clear by mid-day. High temperatures will be stuck in the 60s for
areas in the marine layer, and in the 80s for the warmest inland
valleys. Lows will mostly be in the 50s. By early next week, the
global models agree that the jet stream, which has been running
E-W across the PNW, will become meridional, with a long wave
trough taking aim at California. This trough pattern will persist
through next week, bringing a few weak cold fronts, some cooler
weather, periods of stronger NW winds, and even the chance for
some very light rain, although the air mass looks pretty dry.

&&

.AVIATION...
(06Z TAFS)
Issued at 1037 PM PDT Wed May 15 2024

Currently a mix of VFR-LIFR at the terminals. As the marine layer
continues to slightly compress, IFR-LIFR conditions are to be
expected at all terminals overnight with the exception of SFO
which is expected to at least get a low-end MVFR ceiling. Widespread
VFR and onshore flow will prevail by tomorrow afternoon.

Vicinity of SFO...Currently VFR with westerly flow. Confidence is
high that the terminal will get a ceiling overnight with the
uncertainty lying on whether it will be low-end MVFR like what has
been observed the last two nights or if it will be affected by
the compression of the marine layer and dip to IFR. Either way,
VFR to prevail by late morning tomorrow. Winds become more
southwesterly through the TAF period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently LIFR with westerly flow at MRY
and IFR with northwesterly flow at SNS. SNS is expected to further
deteriorate to LIFR with both terminals VFR by tomorrow afternoon.
IFR conditions are slated to return to both terminals by tomorrow
night. Winds will remain onshore through the TAF period.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 1037 PM PDT Wed May 15 2024

Moderate to fresh northwesterly winds prevail as surface high
pressure over the Eastern Pacific continues to weaken. Seas will
also continue to abate through Thursday. By Friday the surface
high strengthens and moves eastward, strengthening northwesterly
breezes and building wave heights through the weekend and into
next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM Thursday to 3 AM PDT Friday for
     Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Sarment
MARINE...DialH

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