704
FXUS66 KSEW 291610
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
910 AM PDT Fri Aug 29 2025

.SYNOPSIS...Upper level ridging will bring dry conditions to
western Washington today before shifting eastward by this
evening. An upper level low off the coast will influence the
area this weekend, bringing slightly cooler temperatures and
only a slight chance for showers. Upper level ridging returns
Monday, bringing a return to warming temperatures and dry
conditions.

&&

.UPDATE...Generally quiet conditions across the region this
morning. There remains widespread cloud coverage and a few
isolated light radar returns centered over Kitsap County. The
current forecast is on track and no updates are planned this
morning. -Wolcott-

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...Latest satellite imagery
continues to show the upper level center or circulation still in
place over W WA this early morning, however shifted northward
from 24 hours ago. For the southern three-quarters of the CWA,
this has resulted in a more typical west-to-east steering flow.
From the Skagit/Whatcom county line and on northward, a more
monsoonal east- to-west steering flow remains. While this
impacts the mid to high level clouds over the area, it has
little effect on the low clouds/marine stratus along the coast.
Switching over to radar, there is a curious band of echoes
located over northern Pierce and southern King counties as of
145 AM PDT...stubbornly in between any ASOS stations, so it is
difficult to see if they are actually precipitating. Their very
presence, yet low intensity, suggests that at least some
isolated spots in the south Sound and around the immediate
Seattle metro area could see a stray sprinkle before
sunrise...but no significant rainfall is expected.

As stated in the synopsis, the main weather feature today will be
upper level ridging building over the region which will slowly burn
off any cloud cover for the interior while coastal stratus appears
to be a little more stubborn, in at least some part due to the upper
level low off the coast, but that will be discussed more in-depth
momentarily. High temps today will be on average 1-3 degrees warmer
than yesterday with most inland locations in the upper 70s to lower
80s while water-adjacent spots will run in the mid 60s to around 70.

The main feature for the weekend, the upper level low off the coast,
continues to remain organized but subsequent model runs from 24
hours ago to current have been persistent in associating less and
less moisture with the feature. So while some slight cooling, down
into the mid 70s to around 80 for the interior, is still on tap for
Saturday...the chances for showers have dipped with only slight
chance wording /10-20 pct/ in the forecast...and the higher end of
that is mainly over the higher terrain of the Olympics and Cascades,
with possibly similar chances over the islands. Timing for this
remains more of an overnight Saturday/early Sunday morning event, if
it occurs. Generally dry conditions resume for most of the day
Sunday, even though the proximity of the upper low will still keep
daytime highs below 80.

18

.LONG TERM /MONDAY THROUGH THURSDAY/...Intensifying upper level
ridging to the east of the area looks to cause the upper low to
retrograde back out over the Pacific waters, resuming its influence
over W WA for the remainder of the forecast period. Daytime highs
are expected to increase each day, with 90s returning to inland
locations as early as Wednesday for Cascade valleys...becoming more
widespread in the interior lowlands Thursday. The coast and other
water-adjancent locations will generally remain in the lower to mid
70s for most of the long term period...the only exception could be
Thursday where some potential offshore flow could nudge temps into
the mid to upper 70s.

18

&&

.AVIATION...IFR/MVFR stratus along the coastline with VFR conditions
and mid level cloud ceilings elsewhere. Light onshore flow early
this morning will allow stratus to gradually fill in inland, but is
favored to stay west of the Puget Sound and I-5 corridor over the
Southwest Interior. Stratus will dissipate and burn off by 18z,
but areas like KHQM and KCLM will struggle to break out today.
Mid level clouds will thin out by the late morning as the upper
level disturbance overhead dissipates with VFR continuing
persisting for interior terminals.

KSEA...VFR conditions with some passing mid level clouds early this
morning. Winds trying to become northwesterly late this afternoon
with the wind direction ending up in the 250-280 degree range
generally staying between 4 and 8 knots.

15/Mazurkiewicz

&&

.MARINE...Light south to southwesterly surface winds will
continue over the coastal waters today. Periodic onshore flow will
bring westerly pushes across the Strait of Juan De Fuca each
evening, with the strongest push Saturday evening that may reach
Small Craft Advisory criteria.

Combined seas around 2 to 4 feet look to continue through the
weekend and into the first half of next week before building to 4 to
6 feet.

15

&&

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

&&

$$