Rip Current in California, June 24, 2021

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1050 AM PDT Thu Jun 24 2021

.SYNOPSIS...Low clouds this morning turning sunny by midday with
temperatures running a few degrees below normal inland. Gradual
warming trend Friday followed by more significant inland heat this
weekend. Seasonably warm and dry pattern continues next week.

&&

.DISCUSSION...as of 3:52 AM PDT Thursday...Low clouds cover much
of the Bay Area coast and valleys early this morning with
temperatures hovering in the upper 50s to around 60 degrees as SST
have warmed to around 59 degrees given the recent ease of
upwelling northwest winds. The light nw winds over the ocean have
been induced by upper level low pressure that continues to wobble
just west of the Golden Gate and clearly shows up on water vapor
imagery. Cloud bases are fairly high this morning due to the
proximity of the upper low and disrupted inversion layer. There
could be some drizzle this morning as the sun comes up but no
other precip for the Bay Area. Latest model solutions do suggest
the synoptic lift associated with the upper low will allow for a
solid round of thunderstorms across the Central Sierra this
afternoon. As skies turn sunny this afternoon look for highs in
the 70s throughout the Bay Area with mainly lower 80s inland
keeping the below normal trend for inland highs.

The upper low will rapidly fill and dissipate overnight as the
much ballyhooed ridge over British Columbia intensifies while high
pressure west of Baja California ridges northward as well. Expect
a modest warming trend for Friday as the ridge starts to build and
temps warm closer to normal for inland areas. Saturday should see
more rapid inland warming as the ridge to our north amplifies and
sets up an odd pattern with an almost rex block type pattern along
the West Coast. The hottest weather looks to remain well to our
north this weekend. However the interior valleys will warm and
temps could reach triple digits for the far interior North/East
Bay as well as the interior Central Coast by Saturday. However
much of the Bay Area should remain seasonably warm with 90s
staying away from the Bay. No heat headlines expected at this
time.

Models indicate Saturday may be the hottest day this weekend with
a few degrees of cooling Sunday into Monday followed by another
warming trend by Tue/Weds.

&&

.AVIATION...As of 10:55 AM PDT Thursday...For the 18Z TAFs. Marine
layer was similar if not slightly deeper in depth versus 24 hours
ago, with tops around 3200 feet. Satellite imagery shows clearing
across the interior and North Bay while stratocumulus lingers
across the rest of the Bay Area and Monterey Bay. Thus, lingering
FEW-SCT-BKN possible through the remainder of the morning,
becoming VFR by the afternoon. Ensemble/model data suggests the
marine layer will return early again along the coast later today,
as early as 00Z, but likely closer to 02-04Z near the coast, with
a later return inland, ie 06-09Z for the interior. Compression of
the marine layer will also be evident beginning tonight as high
pressure builds in, meaning lower tops (down from 3200 to 2000
feet tonight), lower bases, and less widespread coverage of the
marine layer across the region. Localized IFR to brief LIFR
possible late overnight into sunrise Friday. Otherwise, light to
locally breezy onshore winds.

Vicinity of KSFO...Stratocumulus over the South Bay including
KSFO/KOAK, thus lingering FEW-SCT-BKN may impact terminal over the
remainder of the morning before clearing out to becoming VFR for
the afternoon. Breezy onshore winds this afternoon. Marine layer
slowly returns between 04-06Z FRI then thickens overnight.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...Stratocumulus over the Monterey Bay is
eroding from the interior towards the Bay, leading to patchy cigs
of FEW-SCT-BKN through the remainder of the morning, becoming VFR
by the afternoon. Breezy onshore winds during the afternoon,
otherwise light winds. Marine layer returns as early as 00-01Z
along immediate coast, beginning to impact KMRY/KSNS between
02-05Z FRI.

&&

.MARINE...as of 10:41 AM PDT Thursday...Light wind and seas over
the coastal waters through Friday as a  mixed swell passes through
the waters. Northwest winds gradually  increase later Friday and
through the weekend with light seas  increasing by Sunday as
northwest winds strengthen.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...None.

PUBLIC FORECAST: RWW
AVIATION: DRP
MARINE: DRP

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