Sneakerwave in California, May 16, 2021

Area Forecast Discussion
National Weather Service San Francisco Bay Area
526 PM PDT Sun May 16 2021

.SYNOPSIS...Cooler than normal temperatures are forecast today
as marine stratus intrudes inland again. Slight warming is likely
Monday and Tuesday, mainly for inland areas, before temperatures
cool below normal once again during the second half of the week.

&&

.DISCUSSION...as of 2:17 PM PDT Sunday...Stratus has retreated
toward the coast but is still holding on to much of the coastline.
A steady onshore push is keeping most of the Monterey Bay area,
along with the SF peninsula under the clouds. These areas might
not see any clearing today. Away from the coast, sunny skies are
prevailing and temps are a few degrees higher than at this time
yesterday. Will likely see 70s in South Bay, East Bay, and farther
inland. Otherwise, 50s and 60s near the coast.

Deep marine layer will allow another onshore stratus push
overnight, with more patchy valley/coastal fog and drizzle
possible. Ridging builds in tomorrow, so some compression of the
marine layer can be expected with more clearing closer to the
coast, and a few degrees of warming. Not much change expected for
Tuesday, as we stay under weak ridging.

Wednesday, a fairly potent trough digs into the PacNW which will
significantly cool the boundary layer. Surface temps will see a
corresponding drop, with the steepest decline inland. A low-level
jet will also develop along the coast bringing some gusty NW winds
onshore. Could see gusts 30-40 mph in the afternoon along the
coast. Thursday, the trough digs into CA, setting off continued
gusty winds. Temps will also continue their downward trajectory,
with the most pronounced decline inland. This would translate to
MaxTs around 10 degrees below normal inland, but closer to 5 near
the coast. Any precip chances appear very low, as the associated
upper low stays to our north and east.

We may experience slight warming Friday, but more likely over the
weekend, as the closed upper low moves over the Great Basin. Temps
appear to climb close to normal.

&&

.AVIATION...As of 5:25 PM PDT Sunday...For the 00z TAFs. The
afternoon saw clearing skies for the SF Bay and interior areas but
marine stratus persisted along the coast and inland around the
Monterey Bay. Low clouds will begin to filter into the SF Bay and
move inland this evening, leading to widespread MVFR conditions
through the night. The pattern may allow for compression of the
marine layer leading to lower ceilings, but confidence is low that
this will lead to IFR at isolated terminals. Winds will stay mild
overnight but onshore winds will increase tomorrow in the late
morning and afternoon.

Vicinity of KSFO...tatus returns in the evening, calling for MVFR lasting
until Monday afternoon. Winds will reduce slightly overnight and
remain west-south-westerly.Ceilings look to fall as low as 1000 ft
AGL, but cloud cover will begin to thin and lift around 18 to 19z.
Expect a return to VFR conditions for the afternoon.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...Expect MVFR conditions through the night with mild
westerly winds. Ceilings will lower to near IFR conditions in the
late night with a few chances for late night drizzle. Ceilings rise
back to around 2500 ft AGL Monday afternoon with breezy winds, but
clouds will likely remian broken.

&&

.MARINE...as of 05:24 PM PDT Sunday...Generally light to locally
breezy west to northwest winds over the waters the rest of today
and tonight. Northwest winds will gradually strengthen from north
to south beginning tomorrow afternoon ahead of the next weather
system. Coastal jets look to set up in the typical locations by
mid-week with near gale-force gusts possible. These winds will
generate steep fresh swell resulting in hazardous seas condition,
particularly for smaller vessels. Mixed seas continue with a
moderate northwest swell and a longer period southerly swell.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...SCA...SF Bay until 9 PM

&&

PUBLIC FORECAST: Lorber
AVIATION: Murdock
MARINE: DK

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