Small Craft Advisory 207, NWS San Francisco Bay Area, CA

Area Forecast Discussion
National Weather Service San Francisco Bay Area
141 PM PDT Sun Oct 7 2018

.SYNOPSIS...Strong and gusty northerly winds will continue across
the North and East Bay Hills through Monday morning. Locally
gusty winds are also expected in the Santa Cruz Mountains and the
East Bay Interior Valleys. These dry offshore winds will result in
warmer temperatures in all areas Sunday and Monday. A cooling
trend will start on Tuesday as onshore flow returns. Warmer
weather is then anticipated by late next week.

&&

.DISCUSSION...As of 1:41 PM PDT Sunday...Under sunny skies,
afternoon temperatures are warming into the 70s to lower 80s
across the district. Reports of smoke in the East Bay are prompted
by a fire near Vacaville, and the smoke plume can be seen on visible
satellite imagery. Relative humidity values have plummeted into
the upper teens and 20s, and offshore winds continue to gust in the
hills as well as the east bay valleys. Red Flag Warnings and
Wind Advisories remain in effect through 9 AM Monday for gusty
winds and poor relative humidity recoveries overnight. Winds are
forecast to taper off Monday morning when the surface winds
becomes more onshore.

High pressure will keep skies clear through Monday. Temperatures
will be mild with 70s at the coast and 80s inland. Winds are
expected to decrease on Monday with low clouds returning to the
coast by Tuesday. Near-coastal areas are expected to cool off by
5-10 degrees Tuesday and Wednesday, and inland areas will see less
dramatic cooling over the next several days. Medium range models
indicate a blocking ridge building off the coast for slight
warming by the end of the week. Then, ten days out, the blocking
ridge finally moves east as a deep upper trough approaches the
coast. Way too early to know if NorCal will see rain from this,
but rain does get statistically more likely as we get closer to
the end of October.

&&

.AVIATION...as of 10:27 AM Sunday. For 18Z TAFs. The northerly
gradient remains strong (~7.7 mb) and satellite imagery shows
clear skies continue across the area. Mainly clear skies and VFR
conditions are expected to continue through the period with maybe
some passing high clouds. The main concern remains low level wind
shear associated with north to northeast winds aloft. Shear is
expected to decrease late tomorrow morning.

Vicinity of KSFO...VFR through the period with LLWS due to north
to northeast winds aloft. A brief break is expected this afternoon
as winds increase at the surface, but LLWS will resume by this
evening and continue through tomorrow morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the period with increasing
onshore winds this afternoon 10-15 kt. Higher gusts at KSNS
expected.

&&

.FIRE WEATHER...As of 3:00 AM Sunday...Red Flag Warnings are now
in effect for the North Bay Mountains above 1000 feet, the East
Bay Hills and interior valleys, the Diablo Range above 1500 feet,
and the Santa Cruz Mountains above 1000 feet. Although some areas
received more rain than others this past week, this prolonged
period of strong and gusty north to northeast winds will combine
with low humidity values to increase the fire weather danger
across the region.

Strong and gusty north to northeast winds will last through the
early morning hours with the strongest gusts along the ridge
tops. Although some weakening of the winds may occur during the
day on Sunday these winds will increase once again after sunset.
Humidity recoveries will remain in moderate ranges tonight, but
rapidly fall off during the day tomorrow, with little if any
recovery expected on Sunday night.

Another period of gusty offshore winds may be possible again late
in the work week.

&&

.MARINE...as of 8:15 AM PDT Sunday...Northerly winds will
continue over the coastal waters today creating hazardous
conditions. Occasional gale-force gusts will be possible at times
over the northern outer waters and along the Big Sur coast. These
winds will generate steep wind waves across the waters. This will
be especially hazardous for smaller vessels. All mariners
venturing into open waters should use caution. Mixed northwest and
southernly swell will continue through the forecast period.
Expect an increasing southerly swell generated by Hurricane Sergio
to arrive around mid-week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...Wind Advisory...CAZ507-511-512
             SCA...Pigeon Pt to Pt Pinos 0-10 nm
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...SF Bay until 3 AM
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Mry Bay until 9 PM

&&

PUBLIC FORECAST: Sims
AVIATION: AS
MARINE: AS
FIRE WEATHER: W Pi

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