000
FXUS66 KSEW 230350
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
850 PM PDT Mon Apr 22 2024

.UPDATE...High clouds are moving across the area this evening,
with continued northerly winds for most areas. Dry conditions will
continue through Tuesday with an upper ridge, with temperatures
tonight in the upper 30s to mid 40s.

&&

.SYNOPSIS...High pressure will maintain mild and dry conditions
across the region through Tuesday. From Wednesday through the end
of the week, expect a series of disturbances to bring a return of
clouds and precipitation with temperatures trending closer to
seasonal normals. This pattern will remain through the start of
next week with periodic round of mountain snow and lowland rain.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...Mostly sunny conditions
across the region this morning with temperatures climbing through
the 50s and a few spots into the lower 60s already this afternoon.
Surface high pressure will shift eastward into Tuesday as a
thermal trough builds northward near the coast. This will induce
light offshore flow across the region by the afternoon. This will
likely bring relative humidity values down toward the 20-30% range
for a few hours in the afternoon. Fortunately onshore flow looks
to return late in the day which should boost humidities overnight,
but any fine fuels may be receptive to sources of ignition. Expect
temperatures to top out around 70 through the interior.

Increasing cloud cover and onshore flow returns on Wednesday as a
weak disturbance pushes through. Not much moisture with this one,
but light showers are possible in the higher terrain of the
Olympics and Cascades. Otherwise, temperatures trending back
closer to, or slightly below, seasonal normals. Not much change
either into Thursday with another frontal system following. Cullen

.LONG TERM /SATURDAY THROUGH TUESDAY/...While still much uncertainly
in the way of more subtle differences in the pattern through the
extended, overall expect a cool and showery springtime pattern to
continue for the weekend and start of next week. With a trough
likely setting up offshore, expect several rounds of precipitation
as the individual impulses rotate across Western Washington. Snow
levels Friday through the weekend generally hold around 4500 feet
or higher, so most of the snow will be confined to the higher
mountain elevations but can`t rule out a light snowfall down to
pass levels at times. The highest rainfall amounts look to remain
over the Olympics and will have to monitor for any rises, but
amounts remain well below hydrologically impactful rains for most
of the area - of course, the more flood-prone Skokomish River may
be one to nonetheless need to monitor. All that to say, a rather
common springtime pattern of cool and cloudy conditions with
temperatures generally near or slightly below normal for the long
term period. Cullen

&&

.AVIATION...Westerly winds aloft as a weak upper level ridge moves
through the area. VFR conditions are expected to continue through
the TAF period with mostly clear skies, some high clouds moving
through this evening.

Northerly winds with occasional gusts to 20 kt this afternoon,
easing to light and variable tonight. Winds will be slow to get
going tomorrow, light southeasterly/easterly 4 to 8 kt.

KSEA...VFR through the TAF period with high clouds tonight.
Northerly winds 8 to 12 kt with gusts up to 20 kt will ease to light
northerly/variable before becoming southeasterly 4 to 8 kt after
around 18Z tomorrow.

LH

&&

.MARINE...Broad surface high pressure will gradually weaken as a
thermal trough builds along the Oregon coast and a frontal system
moves southward from the Gulf of Alaska. This system will make its
way to western Washington Tuesday night into early Wednesday, but
will largely fall apart by the time it arrives. The next, more
substantial, low pressure system will move through the region on
Thursday. Winds will likely pick up on Thursday with this system
but the exact details are uncertain with evolution and track of
this system.

A push of westerlies are expected into the Central and East Entrance
to the Strait of Juan de Fuca beginning Tuesday afternoon, for which
a Small Craft Advisory has been issued. Winds will ease below
advisory criteria into Wednesday but will remain breezy through
Wednesday evening.

Seas are expected to remain around 4 to 6 ft through the rest of
this week.

LH

&&

.HYDROLOGY...No river flooding is expected through the next seven
days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 2 PM Tuesday to 6 AM PDT Wednesday for
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca.

&&

$$