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

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313
FXUS66 KMTR 221132
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
332 AM PST Wed Nov 22 2017

.SYNOPSIS...High pressure will continue to produce dry and warm
weather across our entire region through Wednesday. Rain chances
return to the North Bay on Thanksgiving, but the rest of the
region is expected to remain dry with continued warmer than normal
temperatures. Dry weather is expected to return to all areas on
Friday. High pressure will move east during the weekend and rain
chances will begin in the north on Saturday and spread across most
of the rest of the region by Sunday night.

&&

.DISCUSSION...As of 9:00 PM PST Tuesday...High pressure building
across the southwestern United States resulted in warming across
most of our region today. Afternoon highs today were mostly in the
upper 60s and 70s with some lower to mid 80s reported in coastal
Santa Cruz County and Monterey County. Three high temperature
records were set or tied today including San Jose (76), Santa Cruz
(81), and the Salinas Airport (82). The only areas that did not
see significant warming today were localized portions of the North
and East Bay. In these areas temperatures were moderated by light
offshore flow advecting a slightly cooler airmass out of the
Central Valley.

No significant changes are forecast through Wednesday. Fog has
already developed at the Sonoma County Airport this evening and
expect patchy dense fog overnight and into Wednesday morning in
the North Bay Valleys. Also, dewpoints have been trending higher
in the East Bay Valleys where we could see somewhat more fog
tonight compared to last night. Temperatures tomorrow will be
similar to today, except perhaps a few degrees warmer in locations
not impacted by easterly flow out of the Central Valley. Record
highs are possible again, primarily in areas that saw record highs
today.

Moist southwesterly flow that continues to bring rain to the
Pacific Northwest and far northwest California will be kept north
of our area by the blocking ridge through Wednesday night. By
Thanksgiving a shortwave trough moving inland across the Pacific
Northwest may weaken the ridge just enough to allow for light rain
to develop in the northern part of our area. However, the models
don`t agree all that well on the specifics. The 00Z NAM and 12Z
ECMWF bring light rain into northern Sonoma County on Thanksgiving
morning, but are dry for all areas by Thanksgiving afternoon. The
00Z GFS, on the other hand, forecasts light rain for most of the
North Bay throughout Thanksgiving Day and also clips the northern
portions of the SF Peninsula and the East Bay with precip by
Thanksgiving afternoon. In any case, Thanksgiving is not expected
to be a wash out by any means, because even the wettest models
forecast very light amounts of rainfall. For nearly all areas
south of the Golden Gate, Thanksgiving will almost certainly be a
dry day with only slightly cooler temperatures.

After a dry Friday, prospects for precipitation gradually increase
through the weekend as the upper ridge shifts to the east,
allowing the trough over the eastern Pacific to move inland over
northern California. Rain chances will primarily be confined to
the North Bay on Saturday, but rain chances will spread south
across most of the rest of our forecast area on Sunday and Sunday
night.

&&

.AVIATION...As of 03:30 AM PST Wednesday...For 12z tafs. Currently
VFR with patchy fog settled into the North Bay. KSTS is still
reporting 1/4 mile visibility. KLVK, KAPC, and KCCR are also still
reporting MVFR visibility with mist. Expecting these conditions
to last through morning. Elsewhere, high clouds continue to pass
over the region, and cigs may turn BKN late this morning or early
this afternoon but will remain VFR.

Vicinity of KSFO...VFR with calm winds. Light winds will continue
into the day with winds becoming W-NW late this morning or early
this afternoon. Moderate to high confidence.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Winds E-SE tonight and into the
morning, becoming onshore 5-10 knots in the afternoon. Moderate
to high confidence.

&&

.CLIMATE...

HERE IS A LIST OF RECORD HIGH TEMPERATURES
ALONG WITH THE MOST RECENT DATE IT OCCURRED.
*SIGNIFIES THERE ARE ADDITIONAL YEARS THE RECORD WAS SET.

TUESDAYWEDNESDAY

SF BAY AREA
.LOCATION................
 HEALDSBURG..............78/192979/1959
 SANTA ROSA..............77/193678/1939
 CALISTOGA...............79/200290/1932
 KENTFIELD...............76/191777/1939
 SAN RAFAEL..............74/196780/1959
 NAPA....................80/192381/1959
 SAN FRANCISCO...........76/200576/2005
 SFO AIRPORT.............70/195874/1959
 OAKLAND AIRPORT.........73/201577/1959
 RICHMOND................74/200274/2002
 LIVERMORE...............80/191580/1915
 MOFFETT FIELD...........74/195075/1959
 SAN JOSE................76/191775/1924
 GILROY..................79/200279/2005

MONTEREY BAY AREA
.LOCATION................
 MONTEREY................78/200580/1954
 SANTA CRUZ..............81/192584/1933
 SALINAS.................84/195878/2015
 SALINAS AIRPORT.........80/193386/1933
 KING CITY...............87/200292/1930

&&

.MARINE...as of 02:22 AM PST Wednesday...Generally light to
moderate winds will continue as high pressure remains over the
coastal waters. Rain chances will return for the northern waters
towards the end of the week and over the weekend. Winds and swells
will increase over the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...NONE.

&&

$$

PUBLIC FORECAST: Dykema
AVIATION: AS
MARINE: AS
CLIMATE: MM

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