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fxus66 kmtr 220504 
afdmtr

Area forecast discussion
National Weather Service San Francisco Bay area
904 PM PST Tue Nov 21 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
European model (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 5:25 PM PST Tuesday...for the 00z taf cycle,
high confidence VFR except patchy shallow ground fog is possible
in the North Bay early Wednesday morning. Cirrus clears tonight
then returns over the North Bay Wednesday morning resulting in
improving nocturnal cooling mainly from the South Bay to East Bay
areas to southern Monterey and San Benito counties. A stable
atmosphere persists tonight into Wednesday with surface winds
mainly calm, which should tend to favor dew on surfaces in valleys
versus fog in the absence of light mixing (3-5 knot) winds.

Vicinity of ksfo...VFR, light winds.

Sfo bridge approach...VFR.

Monterey Bay terminals...VFR. Winds light east-southeast tonight and Wednesday
morning, becoming onshore 5-10 knots Wednesday afternoon.

&&

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 4:32 PM PST Tuesday...high pressure over the
region will result in light to moderate winds over the coastal
waters. Rain chances will return to the northern waters towards
the end of the week. West to northwest swell will increase over
the weekend.

&&

Mtr watches/warnings/advisories...
...

$$

Public forecast: dykema
aviation: canepa
marine: mm
climate: mm

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