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000
FXUS66 KSEW 162155
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
255 PM PDT Tue Apr 16 2024

.SYNOPSIS...A mixed bag of northwest springtime weather is on
track through early next week. Clearing and dry conditions
overnight will bring a chilly start Wednesday followed by a
warming trend into the weekend. A weekend system will bring a
chance of rain and showers followed by a chance of drier weather
to start the new week.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...Scattered showers
with a mix of sunshine will retreat to mainly the mountains and
diminish altogether this evening. Cant rule out the chance of a
bit of limited thunder before things really wind down this
evening, especially over the northern Cascades.

Clearing and cool conditions overnight will set the stage for
some areas - mainly south of Puget Sound - to see some late season
frost as temps dip near or just below freezing. The frost
advisory remains in affect for Wednesday morning between 2 and 9
am. Lows throughout the interior lowlands will dip into the 30s.

Upper level ridge continuing to build offshore into Northern
British Columbia with dry north northwesterly flow aloft over the
area Wednesday. Temperatures will warming after a cool start with
highs near 60. Wednesday night will remain dry and on the cool
side, but perhaps a bit warmer than tonight. A bit warmer Thursday
despite a fairly dry upper level trough brushing the area. This
will bring a few more mid and high clouds but with low level flow
turning weakly offshore temperatures will reach into the 60s.
Ensembles continue to consistently show an upper level ridge
rebuilding over Western Washington Friday with weak low level
offshore flow, Friday continues to be a safe bet for the warmest
day of the forecast period with highs in the 60s and the warmer
locations near 70. The upper level ridge is expected to shift
east Friday night into Saturday setting the stage for a
weakening front to move into the area.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...Cooler and showery weather
expected Saturday as a weak system moves inland Saturday into
Saturday night. There remains a good chance at a quick rebound
into Sunday, with drier conditions and near normal temperatures
with low level onshore flow. More higher pressure Monday with a
chance of offshore flow may help boost temperatures to start the
week into the mid 60s.

&&

.AVIATION...Scattered showers continue across western Washington
this afternoon. Most showers should be light and pose little impact,
though a few cells may bring a short period of heavy rain, low
ceilings, and limited visibility if they pass directly over the
terminal. All terminals reporting VFR conditions with a scattered
cumulus field. Showers should taper off tonight, and clouds should
decrease in coverage. Mostly clear skies expected tomorrow.
Conditions remain VFR through the TAF period.

Winds light northwesterly through the Puget Sound terminals, with
breezier winds being reported along the coast and through the north
interior. Winds should decrease tonight, becoming light and variable
by early tomorrow morning. Northerly winds pick back up again
tomorrow.

KSEA...VFR conditions with BKN to SCT skies. Decreasing shower
coverage in the area and decreasing clouds tonight, with VFR
conditions expected through the TAF period. Winds northerly 4 to 8
kt, decreasing tonight to light southerly after around 04-06Z
tonight. Winds pick back up around 18Z to northerly 8 to 12 kt.

LH

&&

.MARINE...Northwesterly winds and onshore flow will continue today
and into Wednesday as a surface high pressure ridge continues to
work its way towards the coastal waters. Winds will turn offshore on
Thursday and into Friday as a thermal trough develops along the
coast. Relatively calm winds expected through the rest of the week,
with the only exception being through the Central Strait of Juan de
Fuca, which may see periods of breezy winds Thursday and Friday. The
next frontal system will traverse the region on Saturday.

Steep seas this afternoon with waves 6 to 7 ft at around 8 seconds,
for a Small Craft Advisory continues through this afternoon for the
coastal waters and the West Entrance to the Strait of Juan de Fuca.
Waves will become less steep as seas decrease to 3 to 5 ft early
tomorrow and will remain there through the end of the week.

LH

&&

.HYDROLOGY...No river flooding expected in the next 7 days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Frost Advisory from 2 AM to 9 AM PDT Wednesday for Hood Canal
     Area-Lower Chehalis Valley Area-Southwest Interior.

PZ...Small Craft Advisory until 5 PM PDT this afternoon 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-West Entrance U.S. Waters
     Strait Of Juan De Fuca.

&&

$$