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000 
FXUS66 KMTR 080612
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1012 PM PST Sat Dec 7 2019

.SYNOPSIS....Scattered showers will continue overnight and into
Sunday morning. Showers will end from north to south on Sunday 
afternoon. Dry conditions are then forecast for most of next week,
except for light rain chances late Tuesday and Tuesday night and 
then again late in the week. Temperatures will be near seasonal 
averages through next week. 

&&

.DISCUSSION...As of 8:45 PM PST...A line of intense showers
associated with an upper trough near the northern California coast
produced very heavy rain in San Francisco this afternoon. Rain
rates in excess of an inch per hour in the City resulted in 
widespread street flooding. Heavy downpours occurred locally 
elsewhere in the Bay Area during mid to late afternoon. Showers 
have since tapered off and radar shows most shower activity 
is currently across Monterey and San Benito Counties, with only 
widely scattered showers farther to the north. Expect some showers
to produce brief heavy downpours overnight, mainly across the 
southern half of our forecast area. Heavy rain across the Kincade
burn scar appears unlikely from this point forward, and so the 
Flash Flood Watch for that area in Sonoma County will be allowed 
to expire at 10 pm.

Gusty south to southwest winds occurred today as a surface low 
tracked inland near the CA/OR border. Wind gusts up to 50 mph were
common at higher elevations this afternoon and local gusts up to
40 mph occurred near the coast. Winds have been gradually 
subsiding this evening, and a trend towards decreasing winds is 
expected to continue for the remainder of the evening as the 
surface low moves northeast and weakens.

Scattered showers will continue into Sunday morning as the upper
trough gradually tracks to the southeast across California.
Showers will taper off and end after the upper trough axis passes,
which is expected to occur in the North Bay by late morning and
across the southern portions of our area by late afternoon.
Additional rainfall through Sunday is forecast to range from a
quarter to half inch in most areas, with locally higher amounts
possible in the coastal hills.

A high amplitude ridge is forecast to build over California on
Monday and this will result in dry conditions across our entire
region through at least Tuesday morning. A weak system is then
forecast to bring a brief period of light precipitation to
northern California from late Tuesday afternoon through Tuesday 
night. Rain chances during this time frame will be highest across
the North Bay, with lower chances farther to the south. A broad 
upper ridge is then expected to build off the southern California 
Coast during the second half of next week, resulting in generally
dry and mild conditions except for the potential for another 
brief round of light rain in the North Bay late in the week.

&&

.AVIATION...as of 10:12 PM PST Saturday...MVFR except IFR-LIFR 
in showers with an amplifying mid to upper level trough tonight 
and Sunday morning. Dry weather returning Sunday afternoon and 
night. 

Vicinity of KSFO...MVFR ceiling with showers tonight and Sunday
morning. Southwest wind tonight shifting to west by late Sunday 
morning.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR-MVFR ceilings with showers, possibly
heavy at times, surface wind from the south. Winds shifting to 
west to northwest by Sunday afternoon.

&&

.MARINE...as of 9:57 PM PST Saturday...South to southwest winds
will diminish through this evening. A moderate west swell continues
through Sunday. Wind waves will ease tonight as winds diminish.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...Flash Flood Watch...CAZ506-507

&&

$$

PUBLIC FORECAST: Dykema
AVIATION/MARINE: Canepa

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