278
FXUS66 KSEW 031510
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
810 AM PDT Thu Jul 3 2025

.UPDATE...
No changes overall to the forecast this morning, updates to the
aviation and marine forecasts can be found below.

&&

.SYNOPSIS...
Seasonably warm weather with highs near normal the next couple of
days are expected as a weak trough lifts through the area,
bringing an increased onshore flow this weekend. A warming trend
is expected by late this weekend and early next week as a ridge of
high pressure aloft builds in the Western US.


&&

.AVIATION...Weak upper level trough remaining offshore into
Friday morning. West southwesterly flow aloft becoming southerly
this evening. In the lower level onshore flow continuing through
Friday.

Stratus deck from Skagit county to Northern Pierce county will
dissipate later this morning. Ceilings mostly low end VFR in the
stratus deck with pockets of MVFR. MVFR stratus deck along the coast
and Puget Sound will dissipate late morning/early afternoon. Just
some high clouds all areas later this afternoon into tonight. MVFR
stratus deck reforming along the coast later this evening. Stratus
moving inland Friday morning but staying west of Puget Sound.

KSEA...Low end VFR with low level SCT clouds. Stratus expected to
scatter out by 18z with just high clouds into Friday morning.
Southwest wind 4 to 8 knots becoming northerly between 22z-00z this
afternoon. Northerly winds continuing into Friday morning.

15

&&

.MARINE...High pressure will remain in place across the coastal and
offshore waters this week with thermally induced low pressure east
of the Cascades. A weak front will dissipate over the offshore
waters Saturday.

Diurnal westerly pushes through the Strait of Juan
de Fuca each evening through the weekend. Friday evening looks to be
the strongest push with another round of small craft advisory winds
likely for the Central and Eastern Strait.

Seas will remain between 4 to 7 feet through the period.

15


&&

.PREV DISCUSSION... /issued 318 AM PDT Thu Jul 3 2025/

SYNOPSIS...Increased onshore flow will bring seasonal conditions
today. A weak trough will move inland on Friday followed by zonal
flow through the weekend with mostly dry weather and average
temperatures. High pressure will build into the region, promoting
warmer conditions across western Washington.

SHORT TERM /TODAY THROUGH SATURDAY/...An upper-low is currently
traversing across BC while weak troughing resides offshore. Here
locally we`re somewhere in between - in a regime of quasi-zonal
flow aloft. Closer to the surface, conditions are dry but partly
cloudy as weak convergence fills across the Puget Sound region and
marine stratus trickles along the coast and into the SW interior.
For today, pleasant weather is in store as cloud coverage
gradually decrease. High temperatures will top out in the lower
to mid 70s throughout interior while the coast remains cooler,
generally in the 60s. Marine stratus again Thursday night, but not
as expansive. Overnight lows will into the upper 40s to lower
50s.

Weak troughing aloft positions overhead on Friday before exiting
on Saturday. Guidance is in firm agreement with moisture remaining
well east of the CWA. But, can`t rule out a slight chance (15%) of
PoPs over the north Cascades on Friday evening. Zonal flow aloft will
reposition on Saturday as increased onshore flow invites more
cloud coverage to start the day. Seasonal temperatures are favored
to continue for both Friday and Saturday with mostly dry
conditions persisting as well.

LONG TERM /SUNDAY THROUGH WEDNESDAY/...Zonal flow is favored to
into early next week, resulting in continued seasonal
temperatures and periods of morning clouds and afternoon sunshine.
Then, the Four Corners High will increase in strength, leading to
rising heights over the region towards midweek. Here, we could
see warmer temperatures evolve into the forecast but no
significant threat of HeatRisk is expected at this time.

McMillian



&&

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

$$