214
FXUS66 KSEW 282143
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
243 PM PDT Sat Jun 28 2025

.SYNOPSIS...High pressure will begin to build across the region
into the first part of next week. Temperatures will increase into
the 80s for much of Puget Sound and the South Interior, and a few
Cascade Valleys may break 90 on Monday. The pattern will cool down
mid week with a trough passing through. There is a slight chance
of showers in the Cascades with this trough, otherwise remaining
areas will stay dry with increased cloud coverage.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...Satellite this afternoon
shows a lot of cloud coverage beginning to clear across western
WA. There remains groups of cumulus spread across much of the
region, and the trend is for the clouds to continue to clear out
going into the afternoon and evening. Overhead a zonal flow is
becoming more meridional over the Pacific Northwest as a ridge
begins to amplify tonight into Sunday. For this afternoon: highs
will still be cool/close to normal (thanks to the cloud coverage),
with highs expected to break the 70s across most interior places,
and stay in the 60s along the coasts.

With the ridge amplifying early next week, and surface high
pressure building, temperatures will increase Sunday through
Tuesday under mostly clear skies (Monday being the warmest day).
Highs Sunday will climb into the upper 70s to mid 80s across the
entire region (except for higher elevations and coastal areas
which will stay in the mid 60s to 70s). Could potentially see a 90
around Matlock/Elma areas Sunday afternoon. Monday will see
temperatures increase a few degrees across the entirety of
western WA (for more 90 degree temps likely in the Southwest
Interior and for some Cascade Valley areas). The temperatures will
drop several degrees Tuesday as the ridge weakens and the flow
becomes more zonal. The Pacific Coast/Northwest Olympic areas will
see the best cooling Tuesday (thanks to morning clouds and a
stronger push of some onshore cooler air).

HeatRisk for the region will remain mostly yellow/minor Sunday
through Tuesday (with Monday having the largest area of
moderate/orange HeatRisk in the Cascade Valleys/South Puget
Sound/Southwest Interior areas). Additionally, relative humidity
(RH) values could drop substantially due to the warmer/drier air
Monday (combined with light northeast winds) - dipping down to
25-35% during the day.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...As onshore flow
increases on Wednesday, high temperatures will remain below 80 for
much of the region as the flow becomes more zonal. An approaching
shortwave trough Wednesday through Thursday will increase cloud
coverage for much of the region (with still some sun getting
through late morning and afternoon). The trough at this time is
only expected to produce a few showers in the northern Cascades.
However, this may change some as models are still in limbo with
the 4th of July weekend being either warm and dry, or cool with
potentially some showers.

HPR

&&

.AVIATION...High pressure builds over the region tonight and
Sunday for dry and stable conditions. Low clouds will continue to
scatter out this afternoon and evening with a trend toward VFR.
Northerly winds at the surface. 33

KSEA...VFR conditions prevail. N winds increasing to 10-15 kt
Sunday afternoon. 33

&&

.MARINE...High pressure over the offshore waters will lead to
varying degrees on onshore through through early next week.
Strongest pushes look like Monday night and Tuesday night, with
gales possible Tuesday night. A weak front will cross the waters
on Wednesday. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&

$$