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fxus66 ksew 151632 
afdsew

Area forecast discussion
National Weather Service Seattle Washington
832 am PST sun Dec 15 2019

Update...scattered showers continue this morning from around
Puget Sound into the Cascades in northwest flow aloft as upper
ridging begins to build offshore. Shower activity should diminish
by afternoon with some additional light snow accumulations
expected in the passes. Drier conditions expected for the interior
tomorrow, but a warm front brushing the coast should bring some
light rain to the olympic peninsula. No updates planned for this
morning. Aviation and marine discussions updated below. 27

&&

Synopsis...scattered showers through this morning. High pressure
will build over the area Monday and Tuesday but a frontal system
may brush western and northern portions of the area. Wetter
weather is expected by middle to the end of this week as multiple
systems move through.

&&

Short term /today through Tuesday/...scattered showers across
portions of the central and northern Puget Sound this morning as a
shortwave trough slides through Washington. Small hail reported as well in
spots across King County with cool air aloft. Showers should
diminish early this afternoon for the interior with relatively
dry conditions by this evening into tonight as an upper level
ridge begins to build offshore. Snow showers through today for the
passes with light accumulations, under an inch or two possible,
with the heaviest of bands. Temperatures today will be in the mid
40s.

The upper level ridge will build over the area Monday into
Tuesday, however a warm front moving north across the offshore
waters will bring the chance for showers especially for the
olympic peninsula and north interior Monday afternoon into
Tuesday. Some sunshine will be possible in spots later on Monday
with mostly cloudy skies by Tuesday as the system approaches.
Temperatures will be in the mid to upper 40s. Jd

Long term /Wednesday through Saturday/...the middle to end of
this week will be rather active for western Washington. The first
system will move through Wednesday with a series of shortwaves
through Saturday as troughing develops offshore. Thursday into
Saturday appears the most active on guidance with lowland rain and
mountain snow. Breezy, and perhaps windy, conditions are expected
as well with the series of systems late week. Temperatures will be
a bit above normal in the upper 40s. Jd

&&

Aviation...a weak upper trough will be replaced by an upper ridge
through Monday. Northwest flow aloft. Scattered showers should come to an
end today. There are some patches of fog this morning, but for this
afternoon areas of partial clearing will increase over the area. The
clearing into the evening hours should allow patches of low clouds
and fog to form--more likely in the usually more fog prone areas. A
warm front will clip the area on Monday for some areas of light rain-
-mainly on the coast in the morning.

Ksea...a few showers are lingering over the area but conditions
should generally improve into the afternoon and evening hours. Some
of the other airports like Olympia and Bremerton will probably have
some low clouds and fog tonight--Seattle might avoid that.

&&

Marine...a warm front will clip the area on Monday. After the warm
front brushes by gradients will become more easterly on Tuesday. Two
or three frontal systems will affect the area Wed-Sat.

&&

Hydrology...there are no flooding concerns through the first
half of this week. The latter part of this week will be wet--but
snow levels are not likely to be high enough to put western
Washington into a river flooding situation.

&&

Sew watches/warnings/advisories...
Washington...none.
Pz...Small Craft Advisory from 7 PM this evening to 4 PM PST Tuesday
for coastal waters from Cape Flattery to James Island 10 to
60 nm-coastal waters from James Island to Point Grenville
10 to 60 nm-coastal waters from Point Grenville to Cape
Shoalwater 10 to 60 nm.

Small Craft Advisory from 1 am Monday to 4 PM PST Tuesday for
Admiralty Inlet-coastal waters from Cape Flattery to James
Island out 10 nm-coastal waters from James Island to Point
Grenville out 10 nm-coastal waters from Point Grenville to
Cape Shoalwater out 10 nm-East Entrance U.S. Waters Strait
of Juan de Fuca-northern inland waters including the San
Juan Islands.

Small Craft Advisory from 1 am to 4 PM PST Monday for West
Entrance U.S. Waters Strait of Juan de Fuca.

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