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fxus66 ksew 231608 
afdsew

Area forecast discussion
National Weather Service Seattle Washington
900 am PDT Thu Mar 23 2017

Synopsis...rain will reach the coast this afternoon, and the
interior this evening, as a front moves onshore. An upper trough
will bring showers Friday. Showers will decrease Saturday as the
trough shifts inland. Additional fronts will reach the area Sunday
and around Wednesday.

&&

Short term...radar shows scattered showers on the coast and over
the Olympics. These showers are not associated with the front that
is still well offshore, and they should diminish this morning.
Visible satellite imagery shows a mix of clouds and sun over inland
areas, with more solid clouds on the coast. Rain will develop on the
coast this afternoon, and clouds will increase over inland areas.
Highs today will be mostly in the low to mid 50s.

The front will move onshore this evening bringing rain to all areas,
with decreasing showers behind the front later tonight. The
mountains will pick up some snow but amounts look sub-advisory.
There will also be some breezy to windy conditions coast and north
interior.

An upper trough will move over the area on Friday giving showers.
A shortwave in the flow will enhance showers in the afternoon.
Models have negative lifted indices Friday afternoon over the Puget
Sound region, so there might even be an afternoon thunderstorm or
two. Will wait for later models before introducing what would only
be a slight chance of thunderstorms. The upper trough will slowly
shift inland Friday night and Saturday. There will be enough
lingering instability for a continued chance of showers but the
trend should be toward drying. High temperatures in the low to mid
50s on Friday will fall a bit, into mostly the low 50s on Saturday
behind the front. Burke/Schneider

Long term...previous discussion...the pattern will be progressive
the first half of next week with a series of weather systems
bringing rainy periods interspersed with brief periods of relative
dry weather in between. The first frontal system will reach the area
Sunday. Models are in good agreement with this. Beyond, Sunday,
confidence in the details decreases as models differences increase.
There may or may not be another period of more organized rain Monday
night/early Tuesday. There is higher confidence that a frontal
system will bring another batch of rain Wednesday. Schneider

&&

Aviation...moderate southerly flow aloft today will becoming
strong southwest flow aloft tonight as a trough moves into the
Pacific northwest. Air mass generally moist and weakly unstable
becoming stable this evening. Thunderstorms not expected. Moisture
increasing at all levels this evening. Rain at times along the
coast, then steady rain developing across the area late this
afternoon and early evening.

Cigs should remain VFR today with light rain at times mainly west of
Puget Sound. Steady rain will develop over Puget Sound and the rest
of the interior after 6-7 PM. Brief MVFR is possible with rain
tonight but cigs for the most part will be low VFR 3-4k ft.

Ksea...south-southeast wind 8-13 kt. VFR expected today with
multiple sct-bkn cloud layers from 4-6k ft upwards. Steady light
rain arrives around 6 PM with cigs around 3-4k ft. Dtm

&&

Marine...a strong front will reach the coastal waters later today
and move through the inland waters by around midnight tonight. This
system should produce fairly solid gales of 30 to 40 kt over the
coastal waters late today through tonight, with fairly brief gales
over the eastern Strait of Juan de Fuca and northern inland waters
this evening into early Friday morning. Small craft winds most other
waters. Wind in Puget Sound will stay southerly 10 to 20 kt, but
brief small craft could occur at the north end tonight.

A trough will follow the front on Friday, with fairly widespread
Small Craft Advisory winds likely. Weak high pres will build over
the region Saturday for a period of lighter winds. A relatively
weak Pacific frontal system will move through the region Sunday
night. Dtm/mcdonnal

&&

Hydrology...the White River at r street near Auburn is forecast to
remain near flood stage through at least Friday, primarily due to
releases from Mud Mountain dam. Elsewhere, river flooding is not
expected for the next 7 days.

&&

Sew watches/warnings/advisories...
Washington...none.
Pz...Small Craft Advisory until noon PDT today for coastal waters
from Cape Flattery to James Island 10 to 60 nm-coastal
waters from Cape Flattery to James Island out 10 nm-coastal
waters from James Island to Point Grenville 10 to 60 nm-
coastal waters from James Island to Point Grenville out 10
nm-coastal waters from Point Grenville to Cape Shoalwater
10 to 60 nm-coastal waters from Point Grenville to Cape
Shoalwater out 10 nm.

Gale Warning from noon today to midnight PDT tonight for coastal
waters from Cape Flattery to James Island 10 to 60 nm-
coastal waters from Cape Flattery to James Island out 10 nm-
coastal waters from James Island to Point Grenville 10 to
60 nm-coastal waters from James Island to Point Grenville
out 10 nm-coastal waters from Point Grenville to Cape
Shoalwater 10 to 60 nm-coastal waters from Point Grenville
to Cape Shoalwater out 10 nm.

Small Craft Advisory until 6 PM PDT this evening for East
Entrance U.S. Waters Strait of Juan de Fuca-northern inland
waters including the San Juan Islands.

Gale Warning from 6 PM this evening to 3 am PDT Friday for East
Entrance U.S. Waters Strait of Juan de Fuca-northern inland
waters including the San Juan Islands.

Small Craft Advisory from 3 PM this afternoon to 6 am PDT Friday
for Admiralty Inlet-central U.S. Waters Strait of Juan de
Fuca-West Entrance U.S. Waters Strait of Juan de Fuca.

&&

$$

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