Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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FXUS66 KMTR 201740

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1040 AM PDT Sun Aug 20 2017

.SYNOPSIS...Cooling will continue early this week as an upper
trough of low pressure becomes nearly stationary over the eastern
Pacific. Coastal areas will see little in the way of change with
continued night and morning low clouds and patchy fog.

&& of 8:15 AM PDT Sunday...Widspread clouds this
morning thanks to a deep marine layer and a weak onshore flow at
the surface. Clouds should burn-off toward the coast by late in
the morning. High temperature range will be much less than a
typical August day. Inland most spots will just be in the mid 70s
to the upper 80s while at the coast many areas will be in the 60s
and 70s.

Current forecast appears on track. No major updates planned
although may do a minor update in a bit with information on clouds
for tomorrow morning during the eclipse.

.PREVIOUS DISCUSSION...A nearly stationary upper level closed low
will remain along the Central Coast through early to mid week.
Cooler temperatures will continue this week with comfortable day
time highs expected most places with only far inland locations
experiencing warm to hot temperatures. Wildfire smoke from the
Pacific Northwest began to mix into the air over the Bay Area and
Central Coast yesterday. widespread low clouds and fog over the
coastal waters will be ushered inland this morning on onshore
breezes with returning low clouds and fog again tonight and Monday
morning. Cloud coverage mid-late Monday morning will be
challenging to predict much of it depending upon the depth and
strength of the marine layer, though of course, the farther inland
one is the better chances there are for clear skies during the
solar eclipse. Patchy high clouds are possible over the area
Monday as well. Medium range forecasts indicate some strengthening
of an upper level high over the Desert Southwest and California.


.AVIATION...As of 10:40 AM PDT Sunday for 18Z TAFs. Visible
satellite shows this morning`s overcast skies continuing to mix-
out. Expect VFR conditions at all terminals by late morning,
though Monterey Bay terminals could be a bit later. Haze and smoke
could cause visibilities to lower a bit, but confidence is too
low for any given terminal to include in the TAF. Depth of the
marine layer continues to climb as an upper level low sits off the
southern California coast. Expect the return of the clouds

Vicinity of KSFO...VFR conditions expected to prevail through the
day with increasing west wind around 15 kt this afternoon. Expect
a return to MVFR conditions overnight.

SFO Bridge Approach...Webcams this morning reveal haze and smoke
associated with northern California and Oregon wildfires. Limited
slant range likely through the day. Otherwise, similar to KSFO.

Monterey Bay Terminals...MVFR/IFR cigs at KMRY and KSNS this
morning will likely transition to VFR for the afternoon. Some
guidance suggests KMRY may remain locked in BKN/OVC conditions
through the day, but currently leaning on persistence from
yesterday in the TAF. Will amend if necessary.

&& of 10:30 AM PDT Sunday...Expect moderate northwest
winds to continue over the northern  outer waters through tonight.
Accompanying breezy winds will aid in producing locally steep wind
waves before winds begin to  subside tonight.


     .Tday...SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm from 11 AM
             SCA...SF Bay from 1 PM




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