671
FXUS66 KSEW 150300
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
800 PM PDT Tue May 14 2024

.SYNOPSIS...Dry northwest flow aloft will continue through early
Thursday as high pressure builds offshore. An upper trough will
dip southward on Thursday from British Columbia, bringing cooler
temperatures and periods of precipitation mainly over the
mountains. Unsettled conditions are favored to persist into early
next week with cooler temperatures and chances for light showers
over higher terrain.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...No updates to the
forecast this evening. High pressure aloft will continue to build
off the Pacific coast through Wednesday, allowing for dry
northwest flow over western Washington. Onshore flow will bring in
passing high clouds with temperatures today peaking near the 70
degree mark for much of the lowlands. High pressure will build
towards the Pacific Northwest on Wednesday, allowing for the
drying and warming trend to continue. Most areas will see a few
more degrees in warming with most Puget Sound lowlands peaking in
the mid 70s.

The pattern will shift on Thursday as an upper level trough drops
southward from British Columbia on Thursday. A cold front will
cross the region throughout the day, bringing in breezy winds, a
round of precipitation, and cooler temperatures. The bulk of the
moisture with this system will be focused over the Northern
Cascades with minimal accumulations elsewhere. Snow levels will
drop to 4000 ft by early Friday morning, though any snow
accumulations will be light and will be limited to the highest
peaks. The upper trough axis will swing across the Pacific
Northwest on Friday, maintaining breezy conditions and light
shower activity over the mountains. Temperatures will dip slightly
below normal on Thursday and Friday with most areas seeing highs
in the low to mid 60s.

.LONG TERM /SATURDAY THROUGH TUESDAY/...Forecast confidence
decreases heading into the weekend with ensembles continuing to
show a wide range of solutions. Forecast models highlight the
potential for troughing through the extended, favoring slightly
below normal temperatures and periods of cloudy skies and light
precipitation over higher terrain.

Lindeman

&&

.AVIATION...VFR with passing high clouds. Tonight, expect more
northeasterlies at or under 5 kt with a few terminals having
variable winds. A marine push tomorrow morning may result in low-
end VFR/high-end MVFR cloud decks reaching as far as west Puget
Sound Wednesday morning. Confidence remains low east of stratus
reaching east of Kitsap at this time.

KSEA...VFR with high cirrus/few cumulus clouds in the area. There
is around a 30% chance of MVFR ceilings Wednesday morning (15%
chance of IFR) but due to disagreements in models, confidence at
this time is low in how far the marine push will reach inland.
Northwest winds 5-10 kt becoming northeast at 5 kt overnight.

HPR/AL

&&

.MARINE...High pressure/upper-level ridging will continue to build
over the Pacific through the week, resulting in northwest flow
translating to north/northwest surface winds. A marine push this
afternoon brought gusty winds to the coastal waters and the
Strait of Juan de Fuca that will continue into the early morning
Wednesday. Another push is expected in the strait late Wednesday
afternoon into Thursday, with a much stronger push (potentially
resulting in gales) arriving over the coastal waters/strait Friday
into Saturday (as a result of a trough pushing through). Winds
die down for most areas (except the outer coastal waters) this
weekend into early next week.

Seas will hold around 4 to 6 ft through Friday before increasing 8
to 12 ft from Friday into the weekend, reducing to 6 to 8 ft next
week.

HPR

&&

.HYDROLOGY...The daily hydrology discussion has ended until the
start of the next rainy season; it will only be updated as needed.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for West
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 5 AM PDT Wednesday for Central U.S.
     Waters Strait Of Juan De Fuca-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-East Entrance U.S. Waters Strait Of Juan De Fuca.

&&

$$