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

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FXUS66 KMTR 211143

Area Forecast Discussion
National Weather Service San Francisco Bay Area
343 AM PST Tue Nov 21 2017

.SYNOPSIS...High pressure will bring dry and warmer weather to
the area Tuesday and Wednesday. The high will move east on
Thursday with the next chance of rain late this weekend.

&& of 3:00 AM PST Tuesday...The warm front that
brought rain to the North Bay has lifted north as upper level high
pressure over southern California strengthens and builds north.
This will lead to a big warmup in temperatures today through
Wednesday. Highs will be in the upper 60s and 70s across the SFO
Bay Area with 70s to lower 80s in the southern part of the CWA.
Temperatures on Wednesday will be a couple of degrees warmer than
Tuesday and will be the warmest day of the week. We will be under
a southwesterly flow so nighttime temperatures will remain quite

The ridge will start to flatten on Thursday as an upper level
shortwave moves through the Pacific Northwest. Temperatures
should cool off slightly and there is a slight chance of rain
reaching far northern Sonoma County on Thursday. Partly cloudy but
dry conditions are expected for Friday and Saturday as the ridge
moves a little further to the east.

A weather system will bring a chance of rain to at least the
northern part of the CWA on Sunday. This is consistent with the
GFS solution while the ECMWF is wetter and brings rain chances to
much of the CWA.


.AVIATION...As of 03:44 AM PST Tuesday...For 12z tafs. Currently
VFR across most sites as mid to high level clouds continue to move
over the area. So far not seeing signs of lowering cigs, with the
exception of KSTS. Therefore, keeping the cigs at KOAK and KSFO
VFR for now. With the air still relatively moist, visibilities
may go down to MVFR at times early this morning due to haze. Winds
will remain generally light through the period at around 10 kt or

Vicinity of KSFO...Cigs have remained above 10000 ft so far
tonight, so the tempo group for low cloud bases has been removed
from the 12z taf. Expecting VFR conditions to prevail this
morning with possible MVFR vis due to haze. E-SE winds will
continue into the morning before switching to northwest this

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR conditions expected to prevail with
mainly light E-SE winds this morning. KSNS may see winds up to 10
kt. Winds are expected to turn W-NW this afternoon but remain

&& of 02:17 AM PST Tuesday...As a ridge builds in from
the south, a split windflow pattern is developing, with winds out
of the north over the southern waters and out of the south over
the northern waters. Winds will remain generally light with more
moderate winds in the far northern waters. Chances of rain will
return to the northern waters towards the end of the week. West to
northwest swell will increase mid-week.





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