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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS66 KMTR 250622
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1122 PM PDT Wed Apr 24 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 228 PM PDT Wed Apr 24 2024

A deep marine layer and expansive cloud coverage will keep
temperatures cool through Thursday before stronger winds arrive
Friday. Clearer skies and slightly warmer temperatures are
expected this weekend.

&&

.UPDATE...
Issued at 853 PM PDT Wed Apr 24 2024

Areas of the North Bay coast, East Bay Hills and Santa Cruz
Mountains saw light rain/drizzle today with amounts totaling up to
0.04". Due to abundant cloud cover, temperatures struggled to warm
out of the low-to-mid 60s. Similar conditions will be possible
overnight, but rainfall amounts won`t amount to much and are likely
to range from trace amounts to a few hundredths of an inch.
Overnight temperatures are expected to cool into the mid 40s to
low 50s. No updates are anticipated at this time.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 251 PM PDT Wed Apr 24 2024

Another cloudy and cool afternoon, but with a slightly different
setup compared to yesterday as the the low pressure has moved closer
to the coast. While the low continues to push plenty of clouds
onshore cloud heights and marine layer thickness increased as the
low moved closer. What does that mean? Well it will be slightly
harder for the cloud cover to erode this afternoon.

The low pressure slowly makes its way inland tonight. The deeper
marine layer may limit fog development to only a few patches in the
North Bay, otherwise expect another cloudy night followed by a cool
and cloudy Thursday.

While Thursday continues the trend of cloudy skies, the upper level
pattern shifts, allowing for more northwest flow and bringing back
some breezier northwest winds into the forecast.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 251 PM PDT Wed Apr 24 2024

Still cloudy and cool with some pockets of drizzle for early Friday
as the low pressure exits and the marine layer compresses just
enough for lower clouds. Friday`s pressure gradient change from the
low`s exit will make for even breezier conditions for Friday
specifically for higher peaks and along the Big Sur coast. The more
active winds will allow for better clearing of cloud coverage in
the late afternoon

While the new upper level pattern still allows for onshore flow,
cloud cover becomes less pervasive. While the immediate coast will
continue to struggle with cloud cover, most areas slightly more
inland and well into the interior will see quicker clearing times.
This will place most areas back into the 60s and 70s into the next
work week, while the coast will stick to around 60 degree highs.

Longer term models still struggle with the next pattern change at
the beginning of next month. While the ECMWF families place rain
chances back into the forecast, others favor more cloudy and drizzly
conditions, and a few keep the moisture well to the north.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 1122 PM PDT Wed Apr 24 2024

Cloudy and overcast conditions prevail once more, though unlike last
night which saw largely VFR conditions prevailing despite cloud
cover, tonight is likely to see widespread MVFR CIGs as the marine
layer continues to compress as a shortwave ridge builds. This will
lower CIGs to around 1500` for most terminals. At this time, not
expecting CIGs to deteriorate below MVFR, though Monterey Bay
terminals may come close briefly in the mid morning Thursday. Most
terminals clear late in the morning of Thursday, with winds
steadily increasing out of the west to become moderate to strong,
and gusting 20-25+ knots well into the evening hours. KSFO is
likely to see the strongest gusts nearing 30 knots.

Aside from moderate to strong winds and gusty conditions, models are
in good agreement indicating stratus making an aggressive push
inland near 00Z-02Z Friday. Strong onshore winds help advect these
low clouds inland, bringing widespread MVFR conditions once more.
MVFR lasts beyond the TAF period.

Vicinity of SFO...Satellite shows stratus encircling the majority of
the SF Bay at this hour. CIG heights per the KSFO metar are around
1300` at the moment, ushering in MVFR conditions. Expect MVFR CIGs
to last into the late morning before brief lifting to VFR for a few
hours into the afternoon. Despite improvement to VFR conditions, low
to mid level clouds will continue to be present throughout the
duration of the TAF period. Winds will begin to strengthen and gust
25+ knots out of the west by the time of clearing, with winds
continually strengthening into the early afternoon. Stratus and
subsequent MVFR CIGs will return in the early evening, ushered in by
strong westerly winds. MVFR then lasts well beyond the end of the
TAF period with winds slowly decreasing into the late night to
around 10 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR conditions persist throughout the
night, though KMRY is likely to see IFR develop beyond midnight
Thursday as CIGs continually lower. As it stands, there is between a
60-75% chance of IFR CIG development at the most favored times for
KMRY. Elsewhere, chances only stand at about 50% of achieving IFR
conditions, so have left with prevailing MVFR conditions for now.
This will be something to watch closely through the night however as
confidence on maintaining MVFR conditions for terminals outside
KMRY is marginal. Otherwise, KMRY improves to MVFR as CIGs lift
beyond sunrise. Stratus will continue to shroud area terminals
through the TAF period with no improvement to VFR expected.
Chances of VFR are only in the 30-40% range, therefore have gone
with MVFR prevailing through the entire TAF period. Winds onshore,
moderate, and gusting to around 20 knots beginning in the late
morning and continuing through the late night.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
(Tonight through next Tuesday)
Issued at 1122 PM PDT Wed Apr 24 2024

Gentle to moderate NW winds continue into Friday with occasional
moderate to fresh gusts possible throughout portions of the
coastal waters. Gustier fresh to strong winds with near gale
force and isolated gale force gusts possible heading into Friday
as an upper level trough and surface low pressure system move
inland. Moderate period northwest swell will continue to move
through the waters through Saturday. Light long period southerly
swell continues through end of forecast period.
-- End Changed Discussion --

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM to 9 PM PDT Thursday for Mry Bay.

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

     Small Craft Advisory from 3 AM to 3 PM PDT Thursday for Pigeon
     Pt to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 AM Thursday to 3 AM PDT Friday for
     Pt Pinos to Pt Piedras Blancas 0-10 nm.

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

&&

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...AC
MARINE...Kennedy

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