852
FXUS66 KMTR 160404
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
904 PM PDT Mon Jul 15 2024

...New SYNOPSIS, UPDATE, MARINE...

.SYNOPSIS...
Issued at 850 PM PDT Mon Jul 15 2024

Marine layer stratus returning back inland tonight and Tuesday
morning. Cooler weather will continue through mid-week before a
modest warm-up.

&&

.UPDATE...
Issued at 904 PM PDT Mon Jul 15 2024

Onshore winds prevailing with stratus and fog returning inland
tonight and Tuesday morning. Stratus and fog clearing back to the
coastline during the day Tuesday, forecast high temperatures Tuesday
will be similar to today`s high temperatures.

&&

.SHORT TERM...
(This afternoon through Tuesday)
Issued at 1146 AM PDT Mon Jul 15 2024

The trend for cooler temperatures continues as the upper level
trough inches to the north. This will help promote some more onshore
flow tonight causing the marine layer to deepen and push more
inward. This will result in another rinse and repeat of early return
of clouds near the coast tonight, with gloomy mornings along the
coast and some parts inland. Temperatures tonight will be similar to
last night with some areas seeing 1-2 degrees drop, but temperatures
overall will see minimums in the 50s, with some isolated areas in
the 60s. Similar trend for the maximum temperatures on Tuesday, with
1-2 degrees drop. Coastal areas will see max temperatures in the
60s, while inland will see mid to high 70s to high 80s. Higher
terrains, especially near Monterey County and San Benito counties,
may see temperatures in the mid to high 90s.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 1146 AM PDT Mon Jul 15 2024

Quiet weather will continue through Wednesday with marine layer
clouds in the morning and comfortable temperatures in the
afternoon. Winds will gradually shift from SW to NW and strengthen
to a moderate breeze along the coast. Overall nice cool weather
to start the week before a modest warm-up.

Remember that 12 day heat wave we just went through? Remember how
it was caused by a strong, slow-moving high pressure system that
brought descending air and triple digit heat to inland areas.
Well believe it or not, that same high pressure dome is coming
back for a curtain call. Currently centered over the 4 corners
region, this system is still quite strong. The 12Z sounding from
Albuquerque measured a 500 mb height of 5,960m, which ranks in
the top 1% of the historical record. There is very good agreement
in the guidance that this feature will gradually retrograde back
to the west, although it`s not yet clear how far. While the
details are still being ironed out, expect another period of warm
weather late this week and into the weekend. Fortunately, we are
not expecting a repeat of the recent extreme temperatures, but
minor to moderate HeatRisk is expected for the usual inland areas
starting Thursday.

&&

.AVIATION...
(00Z TAFS)
Issued at 506 PM PDT Mon Jul 15 2024

VFR prevails through the mid to late evening today for most
terminals. Winds are currently breezy and onshore, but are expected
to slowly ease into the nighttime as the gradient lessens. Current
thoughts are that stratus is likely to come in later than previous
nights, moreso towards 06Z and beyond for most terminals. A look at
current satellite shows the stratus deck cleared far beyond the
coast, so it will take time for stratus to slowly push back inland
tonight, hence the later return time. This being said, CIGs when
they develop are likely to be MVFR, lasting through the late morning
of Tuesday. VFR conditions and breezy onshore winds will return in
the afternoon Tuesday.

Vicinity of SFO...VFR through the late night tonight, though low
clouds will begin to filter in just beyond sunset. MVFR CIGs are
not expected to develop until closer to midnight, and then last
through the late morning Tuesday. Winds will remain above 7 knots
in the overnight tonight.

SFO Bridge Approach...Stratus will cover much of the tonight and
through the morning Tuesday, with largely MVFR CIGs. Some CIGs
dipping temporarily to IFR conditions are not out of the question.

Monterey Bay Terminals...VFR through the evening today. Some
uncertainty exists as to when stratus will push inland tonight, as
models do indicate at least some low clouds entering the terminal
vicinity this evening, but don`t seem to support as robust stratus
coverage until closer to midnight. Current confidence on MVFR CIG
development prior to midnight is moderate. Although CIGs will
develop in the overnight tonight, the uncertainty lies within the
timing of their development. Moderate confidence on CIGs lowering to
IFR altitudes in the mid morning of Tuesday. Nonetheless, expect
late clearing of CIGs tomorrow morning, generally 18/19Z.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 858 PM PDT Mon Jul 15 2024

Low pressure to the north is helping to support light southerly
winds tonight. Light southerly winds persist through Tuesday,
though turn to become more northwesterly beginning early
Wednesday. These winds will gradually build rough, short period
seas by Thursday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...SO
LONG TERM....Flynn
AVIATION...AC
MARINE...AC

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