Technical NOAA Weather Discussion

000
FXUS66 KMTR 221757
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
957 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 7:20 AM PST Wednesday...Fog continues to be
reported across portions of our CWA this morning, although dense
fog appears to be less prevalent over the past hour. The dense fog
advisory currently in effect will be allowed to expire at 8 AM.

Another round of well above normal temperatures can be expected
today with a ridge of high pressure in place combined with
offshore flow and warm 850 mb readings. Could see a few records
highs especially for locations south of San francisco Bay.
Portions of Monterey and San Benito counties will soar into the
80s.

Dry weather remains on track through Saturday for most of our
region. Just a chance of light rain generally north of San
Francisco on Thanksgiving day. Possible return to a wetter pattern
for next week. The ensembles have been hinting at that. Will be
interesting to see if the operational runs follow suit.

.PREVIOUS DISCUSSION...A light offshore wind has brought areas of
tule fog to the North and East Bay valleys this morning.
Visibilities may locally drop to as low as 1/4 mile before fog
burns off mid- morning.

Upper level high over southern California will bring another warm
day to the region today. As was the case yesterday...the warmest
temperatures will be south of the SFO Bay Area with highs in the mid
70s to mid 80s. Record high temperatures are possible in these areas
again.

The ridge will flatten on Thursday as an upper level trough moves
into the Pacific Northwest. This trough splits off with only the
northern part of the trough moving towards the coast and the
southern portion nearly forms a cutoff low near 35/140W. As a result
of this split just about all of the rain will remain north of the
district. The majority of the models being light rain to northern
Sonoma County Thursday afternoon while the GFS is an outlier
bringing rain chances a little further south into most of the North
Bay and even San Francisco. The forecast goes along with the model
majority. Any rainfall amounts should be under one- tenth of an
inch.

Dry weather returns Friday as the trough moves inland. In the
meantime the upper ridge will move east and the next upper level
trough will be deepening along 140W. This trough will kick the
cutoff low northeast bringing a chance of rain to the North Bay on
Saturday. Rain spreads south over the rest of the district Sunday as
the trough moves through. Lingering showers will persist into Sunday
night mainly from the SFO Bay Area north. Dry weather return early
next week as ridging returns to the area.
&&

.AVIATION...As of 09:55 AM PST Wednesday...For 18z tafs. Lingering
dense fog in north bay valleys, otherwise widespread VFR. Winds
generally light through the period. High SCT-OVC clouds will
gradually descend from 25000 ft down to around 10000 ft through
the taf period.


Vicinity of KSFO...VFR. Light winds. Passing high clouds through
the taf period, with a some low to mid range clouds tomorrow
morning.


SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Light winds. Increasing high clouds
through the taf period.

&&

.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.

                       WEDNESDAY

SF BAY AREA
.LOCATION................
 HEALDSBURG..............79/1959
 SANTA ROSA..............78/1939
 CALISTOGA...............90/1932
 KENTFIELD...............77/1939
 SAN RAFAEL..............80/1959
 NAPA....................81/1959
 SAN FRANCISCO...........76/2005
 SFO AIRPORT.............74/1959
 OAKLAND AIRPORT.........77/1959
 RICHMOND................74/2002
 LIVERMORE...............80/1915
 MOFFETT FIELD...........75/1959
 SAN JOSE................75/1924
 GILROY..................79/2005

MONTEREY BAY AREA
.LOCATION................
 MONTEREY................80/1954
 SANTA CRUZ..............84/1933
 SALINAS.................78/2015
 SALINAS AIRPORT.........86/1933
 KING CITY...............92/1930

&&

.MARINE...as of 09:53 AM PST Wednesday...Split flow, with light
variable winds in the outer waters and  north of Point Reyes
today, with locally breezy north winds from Pigeon Point through
Big Sur coastal areas. Winds increase and turn more northerly
tomorrow. Light to moderate west to southwest swell through the
coming days.

&&

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

&&

$$

PUBLIC FORECAST: Bell/W Pi
AVIATION: DRP
MARINE: DRP
CLIMATE: MM

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Prepared by Boulder-Creek.com Weather at: Wed Nov 22 10:30:02 PST 2017
From the National Weather Service