980
FXUS66 KSEW 060951
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
251 AM PDT Thu Jun 6 2024

.SYNOPSIS...Upper level ridge over Western Washington through
Friday will shift into Eastern Washington Saturday. Weak upper
level troughs will move through Sunday and Tuesday with an upper
level ridge in between the troughs Monday.

&&

.SHORT TERM /TODAY THROUGH SATURDAY/...Satellite imagery shows
flat upper level ridge over Western Washington early this
morning. Just some high clouds near the Canadian border at 2
am/09z. Temperatures were in the mid 40s to mid 50s.

Flat upper level ridge remaining over Western Washington today.
Southwesterly flow aloft will bring some high clouds over the area
at times. Low level onshore flow will keep high temperatures near
normal, in the upper 60s to mid 70s.

Upper level ridge gaining amplitude tonight into Friday.
Temperatures aloft warming with 850 mb temperatures rising from
plus 8C to plus 11C tonight to plus 13C to plus 16C by late
Friday afternoon. Low level flow remaining northwesterly onshore
which will cap the warming from Thursday highs to the 5 to 10
degree range putting highs in the 70s to lower 80s. Lows tonight
with mostly clear skies in the mid 40s to lower 50s. The cool
overnight low temperatures will keep the HeatRisk in the minor
category.

Upper level ridge axis over Western Washington Friday night will
shift into Eastern Washington Saturday. Increasing low level
onshore flow during the day Saturday. Lows Saturday morning a few
degrees warmer, in the lower to mid 50s. Increasing onshore flow
will result in less daytime heating but with the warmer
temperatures to start the day highs will end up being close to
Friday`s highs, in the 70s and lower 80s. The exception to this
will be along the coast where the increasing onshore flow will
cool daytime highs back into the 60s and lower 70s. Little change
in the HeatRisk for the interior.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Extended models in fairly
good agreement with a weak upper level trough moving through
Western Washington Sunday. Most of the moisture with the trough
will be in the mid levels giving the area for some filtered
sunshine. Main impact will be to increase the low level onshore
flow Sunday resulting in cooler high temperatures for the
interior, upper 60s to mid 70s. Highs along the coast in the lower
to mid 60s. There is a chance of showers over the Cascades in the
afternoon.

Temporary weak upper level ridge crossing the area Monday will be
followed by another weak with not very much moisture trough
Tuesday. Both of these features will have little effect on the
daytime highs with mid 60s to mid 70s for the interior and lower
to mid 60s on the coast.

Weak upper level trofiness remaining over the area Wednesday.
Increasing low level onshore flow will drop daytime highs into the
60s and lower 70s. Felton

&&

.AVIATION...West-southwest flow aloft becoming more westerly today
with an upper ridging building into the area. Mostly clear skies
through the TAF period with high clouds at times, especially this
morning. Slight chance of low cigs along the coast, mainly north
coast, along with with patchy fog in river valleys this morning.
Light north winds this morning, increasing this afternoon.

KSEA...VFR cigs with high clouds at times. NE winds generally 6 to
10 kts this morning, becoming more N/NW this afternoon. JD

&&

.MARINE...Northerly winds will continue through Friday, increasing
afternoon and evening for the waters as high pressure builds. Winds
are expected to remain below SCA threshold. Onshore flow will
increase Saturday night into Sunday for potential westerly SCA winds
through the Strait of Juan de Fuca. Onshore flow into next week.
Seas will slowly subside below 10 feet this morning, and remain 5 to
8 feet into Saturday. Seas will then build Saturday night into
Sunday, with seas potentially approaching 10 feet for the outer
Coastal Waters late weekend. JD

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT early this morning 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.

&&

$$