160
FXUS66 KMTR 070420
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
920 PM PDT Thu Jun 6 2024

...New UPDATE, MARINE...

.SYNOPSIS...
Issued at 1215 PM PDT Thu Jun 6 2024

Slightly cooler temperatures today with a further cool down into
the weekend. Another warming trend on the way for early next week.

&&

.UPDATE...
Issued at 919 PM PDT Thu Jun 6 2024

Today remained fairly warm inland with temperatures ranging from the
mid 80s to upper 90s to low 100s in the mountain ranges. Along the
coast, cooler temperatures prevailed with highs in the upper 50s to
mid 60s. In general, temperatures for most areas were cooler today
than they were yesterday with the end of the heat wave in sight and
the heat advisory set to expire tonight.

Beginning Friday, seasonal to slightly above average highs in the
upper 70s to mid 80s are expected inland while coastal areas
continue lingering in the upper 50s to mid 60s. Stratus is expected
to return along coastal areas tonight with elevated fog chances in
the North Bay (particularly for Santa Rosa) and within the Monterey
Bay. For early morning commuters, if you encounter fog while driving
remember to slow down and account for extra time to reach your
destination.

&&

.SHORT TERM...
(This evening through Friday)
Issued at 1215 PM PDT Thu Jun 6 2024

Mid day temperatures running anywhere from 3 to 15 degrees cooler
than yesterday depending on location. Thanks to the upper level
ridge migrating eastward and a transient shortwave trough moving
into the West Coast. This is evident in not only the marked
decrease in temperatures, but via vertical profilers showing a
deepening of the marine layer as large scale subsidence
diminishes. Overnight lows tonight are expected to be about 1-5
degrees cooler than last night, and highs Friday look to be about
3-6 degrees cooler than today...unless you`re along the coast, in
which the only noticeable difference day-to-day will be increased
overnight cloud cover and potentially morning drizzle into the
weekend.

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 1215 PM PDT Thu Jun 6 2024

Things stay pretty quiet through the weekend. Onshore flow and
slightly above average temperatures prevail, and guidance hints at
a deeper upper level trough associated with the deep low in the
Gulf of Alaska sitting offshore of the West Coast into the start
of next week. As previously mentioned, this will likely just
result in increased cloud cover along the coast and AM drizzle for
coastal and high elevation locations through Sunday. By Monday,
the trough begins to break down and become replaced by another
ridge pattern, which leads to our next warm up. At the moment,
ensemble guidance is leading us to believe that it will not be
quite as warm as the last couple of days, but it is a period
we`re watching for potential highlights with Tuesday looking like
the peak based on this forecast issuance.

&&

.AVIATION...
(00Z TAFS)
Issued at 438 PM PDT Thu Jun 6 2024

While VFR is forecast to continue through sunset, flight
conditions will deteriorate quickly at Monterey Bay Terminals by
03Z (IFR cigs/visibility). At Bay area terminals MVFR is forecast
to arrive around 06Z, with MVFR/IFR visibility closer to 10Z at
the North Bay airports. LVK and SJC have around a 10% chance of
MVFR, but the current TAF for these aerodromes is VFR. Largely
onshore flow is forecast through the TAF period with winds
subsiding some after 04 UTC. Confidence is medium in flight
category forecasts and medium to high in the wind forecasts.

Vicinity of SFO...WNW winds will slowly subside through 04 UTC,
though a few gusts to near 25 knots cannot be ruled out. MVFR
stratus is forecast to invade from the west/through the San Bruno
Gap around sunrise tomorrow, with intermittent BR bringing
visibility down to IFR during the AM push. Confidence is high
enough to advertise a brief period of VFR in the afternoon, before
MVFR stratus returns. If the marine layer is deeper than
currently anticipated, MVFR may prevail through the entire TAF
period. The TAF for tomorrow afternoon is a bit more optimistic
with VFR forecast. MVFR is advertised to return in the extended
portion of the TAF, however, additional forecasts will need to
address any IFR ceiling potential.

SFO Bridge Approach...Similar to SFO, though the onset/cessation
of MVFR stratus may differ by up to 1 hour.

Monterey Bay Terminals...Poor flying conditions are forecast
within the next couple of hours with MVFR stratus yielding to IFR
ceilings and visibility. Confidence is medium to high on the
ceiling and visibility forecast. LIFR cigs are forecast to set in
just prior to midnight and prevail through the pre-dawn hours on
Friday. Cigs are forecast to lift into the MVFR category late
morning/early afternoon on Friday, though confidence in the exact
timing is medium to low. In fact, if the marine layer is a bit
deeper, MVFR could prevail until late in the TAF period. For now,
I`ll advertise a more optimistic TAF and we`ll monitor forecast
trends and adjust if needed.

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 919 PM PDT Thu Jun 6 2024

Fog and patchy drizzle will result in reduced visibility through
the pre-dawn hours on Friday across Monterey Bay down to Point
Sur. Winds and seas will remain hazardous for areas along and
north of the Greater Farallones through Friday afternoon where
Small Craft Advisories remain in effect. Elsewhere, winds and seas
are forecast to subside below 20 knots and 10 feet, respectively.
This will be relatively short lived as 20-25 knot winds increase
during the pre-dawn hours on Sunday. Seas will respond later
Sunday morning and into the afternoon, likely necessitating
additional marine headlines.

&&

.BEACHES...
Issued at 339 PM PDT Thu Jun 6 2024

Westerly to northwesterly long period swell will continue to
impact area beaches. Wave periods near 15 seconds and heights near
10 feet are still forecast. The sneaker wave potential will persist
into this evening. The threat for people and animals being pulled
in the water from rocks, jetties, and beaches will also continue.
Inexperienced swimmers should stay out of the water. Observe the
ocean for 20 minutes before relaxing on the beach. Know where
lifeguards are, obey their instructions, and never turn your back
on the ocean!

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement until midnight PDT tonight for CAZ006-
     505-509-530.

     Heat Advisory until midnight PDT tonight for CAZ503-504-506-510-
     512>516-518.

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

     Small Craft Advisory until 3 PM PDT Friday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...Bain
MARINE...Bain

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