346
FXUS66 KSEW 231015
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
315 AM PDT Sun Jun 23 2024

.SYNOPSIS...An upper level trough will produce clouds, cooler
temperatures, and a few showers across Western Washington today.
The trough will weaken tonight and a ridge of high pressure aloft
will begin to rebuild into the area Monday. The ridge will
strengthen as it shifts eastward on Tuesday for dry conditions and
warmer temperatures. Another trough arrives Wednesday into
Thursday for showers and cooler temperatures once again. A weak
ridge late in the week will lead to drier conditions and near
normal temperatures.

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...Clouds have filled in across
most of Western Washington early this morning ahead of an upper
trough moving into British Columbia. Spotty showers have already
been observed across coastal areas and we should see some weak
convergence zone activity develop across Skagit and Snohomish
counties later this morning. QPF will be minimal...a few
hundredths at best. High temperatures will be back below
normal...in the 60s across most of the lowlands.

The upper trough weakens tonight into Monday as it shifts
eastward across interior British Columbia and this will allow
upper ridging to begin rebuilding into the area. Most areas should
see some sunshine return Monday afternoon with temperatures
rebounding to near seasonal norms. Upper ridging gains amplitude
as it shifts eastward into the northern Rockies later Tuesday.
Interior temperatures will warm into the 70s while onshore flow
keeps most of the coast firmly in the 60s.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...Models remain consistent
with an upper trough moving into the region Wednesday and
Thursday. This one has a more southward trajectory than the
current one and looks to provide much of the region with a decent
chance at some measurable precip. And as one would expect,
temperatures will cool back to below normal levels midweek. The
upper trough shifts eastward into the Northern Rockies by the end
of week allowing weak upper ridging to briefly rebuild. With
continued onshore flow, temperatures will be held around seasonal
levels...60s coast...70s inland. 27

&&

.AVIATION...Upper level trough over Western Washington today
moving east tonight. Zonal flow aloft tonight and Monday. In the
lower levels onshore flow through Monday.

MVFR ceilings over most of the area this morning with the
exception of the Central Puget Sound where ceilings are near 5000
feet. Ceilings in the Central Puget Sound lowering to MVFR
14z-16z. All areas ceilings lifting to low end of VFR 20z-23z with
VFR ceilings continuing into Monday morning.

KSEA...Ceilings near 5000 feet lowering to 2000 to 3000 feet
14z-16z. Ceilings lifting back up to near 4000 feet 20z-23z with
VFR ceilings continuing into Monday morning. Southwest wind 8 to
12 knots easing after 03z. Felton

&&

.MARINE...Weak high pressure will build back over the
coastal waters and interact with lower pressure inland today
through Tuesday. Another frontal system will reach the waters
Wednesday. High pressure will rebuild over the coastal waters
Thursday.

Diurnal westerly pushes through the Strait of Juan de Fuca could
result in small craft advisories for the Central and Eastern
Strait Tuesday through Thursday in the evenings.

Swell near 4 feet this morning building to 5 to 7 feet tonight
into Monday. Felton

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT early this morning for
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca.

&&

$$