Small Craft Advisory 55, NWS San Francisco Bay Area, CA

Area Forecast Discussion
National Weather Service San Francisco Bay Area
501 AM PDT Sun Mar 20 2022

.SYNOPSIS...After a chilly morning, mild temperatures and breezy
winds are forecast for Sunday. As a ridge builds, warming and drying
trend then sets up bringing warm temperatures in the 70s and 80s
around the Bay Area by midweek.  Temperatures will likely cool next
weekend as the ridge weakens.

&&

.DISCUSSION...as of 03:19 AM PDT Sunday...The rain has moved
clear out of the region to the south, and the radar has been
returned to clear air mode. Winds around the area started to
increase in the wake of the frontal passage before 10 PM PDT
Saturday night. Surface observations were regularly gusting around
20 mph, with KSFO reaching 30 mph gusts. Clearing skies slowly
crept southward from Sonoma County and over the San Francisco Bay.
Clouds still remain around 2500 to 3000 feet along the Central
Coast, but further clearing can be expected as the sun rises.
Winds have steadily diminish.

The clearing of clouds have also allowed for radiational cooling to
take place. Temperatures are already 3 to 6 degrees cooler than what
they were just 24 hour prior. While wide spread fog is not expect,
it is possible for some patches of low clouds to crop up in isolated
sheltered areas. The bigger impact, particularly for the North Bay
which has been exposed for longer, will be the cooler even chilly
morning lows. Temperatures are forecast to drop into the mid-to-
upper 30s with Santa Rosa leading the charge below 35 degrees
Fahrenheit. Any frost that develops will be limited in spatial
extent as temperatures, though chilly, are expected to remain above
the freezing mark.

Sunday begins the transition day. The front has passed and now
models are in agreement that an upper level ridge will develop and
grow northward from the southeast Pacific. With its development
being gradual in nature Sunday will be mild and sunny with breezy
afternoon winds developing. There is a slight chance for a
strengthening SFO-WMC gradient which will drive stronger offshore
winds aloft Sunday morning. However, while gusts will be strong
above 2000 feet, there is little confidence of it mixing down to the
surface and should remain below advisory threshold.

Ensemble models are projecting a 586 dm ridge to develop west of
Baja by Wednesday. This growing high pressure that will extend over
Central California will drive a warming and drying trend for the
area. Both the Euro and the GFS are resolving 850 mb temps between
13 and 15 degrees Celsius by Wednesday, with the Euro being the more
bullish of the two. While this is a far cry from the 25 to 30 degree
Celsius temps that signal the heat waves of July and August, it will
certainly drive above normal temperatures for the region for the
month of March. Surface afternoon high temperatures could climb into
70s and possibly 80s for interior locations by Wednesday. While it
is not a summer time heat, some locations stand the chance for temps
that are at least 15 degrees above March normal values. Warm temps
will gradually cool into the weekend and the ridge weakens.

In addition to the warm temperatures, as the ridge morphs, the
northerly winds will align to reintroduce offshore winds to the Bay
Area. At this time there is low confidence in the winds mixing down
to the surface. Additionally, though minimal, the recent rains will
help suppress fire concerns. However, their chief impact will be to
further dry the air around the area and in crease localized warming
from downsloping.

Beyond Friday, ensemble models are keeping an active trough pattern
over the Pacific. Most members keep a La Nina track with things by
sending most systems to the Pacific Northwest. There are still a
chance for another system with rain to move toward the Bay Area,
most likely toward the end of the month, but models are wildly all
over the place from timing, location and amount. Still, there is
something to keep an eye on for the future.

&&

.AVIATION...as of 5:01 AM PDT Sunday...For the 12Z TAFs.

Predominantly VFR around SF Bay and MVFR to VFR around Monterey
Bay. Night satellite imagery shows low clouds scattering around
Monterey Bay, while areas to the north are mostly clear. Remaining
clouds should evaporate by early morning, as VFR prevails through
the TAF period. Winds have largely settled down, but are still
locally breezy. Possible LLWS through the morning as northerly
winds between 1000-2000 ft AGL increase to 30-35 kts, while
surface winds diminish. Most likely impacts to interior North Bay
terminals. Breezy to gusty onshore winds this afternoon/evening.

Vicinity of KSFO...Prevailing VFR with clearing skies, and FEW low/mid
level clouds possible through the morning. Moderate WNW winds
10-12 kts, increasing this afternoon. Gusts to around 30 kt are
possible.

KSFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals..MVFR/VFR through the early morning hours,
then prevailing VFR through the period. Increasingly breezy and
sometimes gusty onshore winds this afternoon with FEW mid/high
clouds.

&&

.MARINE...as of 03:17 AM PDT Sunday...Gale force gusts expected
in the outer waters and along the Big Sur coast into Sunday
morning. Northwest winds remain strong into Monday with near gale
force gusts possible. Very steep fresh seas are expected with
these stronger winds that are hazardous to small craft vessels.
Mid period light to moderate west to northwest swell continues
through the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...SCA...Pigeon Pt to Pt Pinos 0-10 nm
             GLW...Pt Arena to Pigeon Pt 10-60 nm until 9 AM
             GLW...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 9 AM
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Mry Bay
             SCA...SF Bay from 3 PM

&&

PUBLIC FORECAST: DK
AVIATION: Lorber
MARINE: Lorber

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