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000
FXUS66 KSEW 170336
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
836 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/...No changes made to the
forecast this evening. The previous discussion can be found below
along with updated aviation and marine sections:

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...Showers have mostly dwindled in coverage this evening.
Mostly clear skies expected tomorrow. Conditions remain VFR through
the TAF period, though cannot rule out a brief period of MVFR
stratus along the coast, potentially impacting HQM from 12-16Z (30%
chance). Onshore flow will continue to ease with light northerly
winds through the day Wednesday, generally 5-10 kt, with gusts to 20
kt possible from 20-02Z at the Puget Sound terminals.

KSEA...VFR as showers continue to dissipate and push well south of
the area. Winds northerly but quickly shifting to the south-
southeast by 06Z. Winds pick back up around 18Z to northerly 8 to 12
kt with occasional gusts to 20 kt possible after 20Z.

Davis

.MARINE...Northwesterly winds into Wednesday as surface high
pressure builds over 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
but winds have dropped below advisory criteria, allowing remaining
Small Craft Advisories to expire this evening. 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.

Davis/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 9 PM PDT this evening 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.

&&

$$