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000
FXUS66 KMTR 060717
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1217 AM PDT Thu May 6 2021

.SYNOPSIS...A cooling trend will return near the coast as the
marine layer redevelops. More widespread cooling across the
interior follows on Thursday and Friday in response to an increase
in onshore flow. Slight warming is then anticipated for the
upcoming weekend, with continued dry conditions.

&&

.DISCUSSION...as of 09:48 PM PDT Wednesday...It was the third and
final day of a hot stretch for the interior of our CWA. The
highest recorded temperatures were once again in interior Monterey
and San Benito Counties. It reached 95 in King City and 96 at
Pinnacles NP, the highest temps so far at any of our climate sites
this season. Tomorrow and Friday, these sites and others in the
interior will see a drastic cooldown of between 10 and 20 degrees,
as a dry cold front sweeps across the area followed by a
shortwave. This will bring temperatures back to nearl normal -
predominantly 70s, so a nice relief. Around the bays, the drop
will be more moderate, but certainly noticeable - 60s will
prevail.

Tonight will feature a deepening marine layer as an upper trough
approaches from the PacNW. Fort Ord Profiler is showing a marine
inversion about 1700 ft deep. This will allow a deeper push inland
of stratus overnight. Already observing low stratus on satellite
imagery around Monterey Bay, and all along the coast, with
an intrusion into SF Bay. These clouds may linger into mid-
morning, but later close to the coast.

Tomorrow afternoon will feature mostly clear skies away from the
immediate coast, and it will become quite breezy and fairly gusty
as the frontal boundary approaches. 20-30 mph gusts can be
expected around the bays, with some 30+ mph gusts possible in
favored coastal gaps and elevated passes. These winds should
settle down by late evening. Rapid cooling of the boundary layer
may disrupt the marine inversion, but some low and mid-level
clouds will persist, with areas of coastal drizzle possible
overnight.

Focus then turns to the weekend with an area of high pressure
bulding over the eastern PAC and an upper low moving over the
interior NW. This setup will create a fairly strong northerly
gradient which will induce some strong northerly winds aloft. NAM
and WRF show an area of 40+ kt winds over Napa and eastern Sonoma
counties with RH`s dropping to 20-30%. Wind gusts 25-35 mph over
the North Bay mountains and East Bay hills will be possible, with
localized 40+ mph gusts. Finer fuels have already dried out from
the previous wind event, so fire danger will be heightened.
Another round of strong winds may occur Saturday night into Sunday
morning as well. Stay tuned for updates.

&&

.AVIATION...As of 12:17 AM PDT Thursday...For the 06z TAFs. It`s
VFR except for stratus and fog /VLIFR-IFR/ moving inland. Onshore
winds and a deepening marine layer will keep stratus and fog moving
inland through morning. Stratus and fog will scatter out by late
morning for VFR and return tonight.

Vicinity of KSFO...VFR except tempo IFR ceiling to 12z this morning.
Onshore wind gusty to 25 to 30 knots in the afternoon and evening.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VLIFR-IFR in stratus and fog this morning,
scattering out to VFR by late morning. Stratus and fog returning
tonight.

&&

.MARINE...as of 08:37 PM PDT Wednesday...Prevailing northwest
winds continue with stronger winds over the waters between Point
Arena and Point Reyes. Expect coastal jets to strengthen on
Thursday to areas south of all prominent coastal points. The
forecast for Friday remains on track as widespread gusty northwest
winds arrive with locally gale force gusts. A pair of lighter
northwest and southerly swells continue and dominated by wind
driven waves.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm from 3 AM
             SCA...Pt Arena to Pt Reyes 0-10 nm

&&

$$

PUBLIC FORECAST: Lorber
AVIATION: Canepa
MARINE: DK

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