FXUS66 KSEW 121644
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
944 AM PDT Thu Jun 12 2025

.SYNOPSIS...A weak upper trough will move into Western Washington
today then remain over the area on Friday. This will lead to 
cooler temperatures, increased cloud cover, and occasional chances
for mountain showers and coastal drizzle. Upper ridging will
weakly rebuild late in the weekend for a modest warming trend
before another trough approaches the area early in the coming
week. 

&&

.SHORT TERM /TODAY THROUGH SATURDAY/...The current forecast 
remains on track with no planned updates this morning. 33

Previous discussion...A weak upper trough will move into Western
Washington late today for a mostly cloudy day ahead and 
temperatures a little below average. The trough will lead to a 
chance of showers across the North Cascades and near the Canadian 
border tonight and Friday as a couple of weak disturbances pivot 
across the region. Otherwise, mainly dry conditions are expected. 

An upper level trough will start to dig southward offshore on
Saturday. This will lead to a slight rise in heights over Western
Washington. Interior high temperatures will edge closer to 
normal, but continuing onshore flow will ensure that coastal areas
will remain mostly cloudy and on the cool side. 

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...The pattern remains rather
static heading into Sunday with an upper trough offshore and weak
ridging over Western Washington. Model agreement is starting to
fall into place early next week more so than the past few nights.
A weak upper trough is slated to move onshore on Monday, but will
probably produce little more than a bump in onshore flow and the
associated slight cooling that comes with it. A majority of the 
ensembles from both the GFS and Euro are now targeting the 
Tuesday/Wednesday period for a somewhat more substantial upper 
trough (by mid June standards) to move into the region and produce
some light precip. It's not shaping up to produce much in the way
of impacts, but it could be the beginning of a more prolonged 
period of cooler, more unsettled conditions that will sharply 
contrast how the month began. 27

&&

.AVIATION...An upper level trough will move across the region 
today with southwest/west flow aloft today and tonight. MVFR stratus 
deck remains in place across the region and with it being a deeper 
layer will expect it to persist through around 19-20z this morning 
before lifting in the interior. Coastal terminals will remain in 
the stratus much of the day. Expect onshore flow to bring another 
widespread stratus push overnight with the Puget Sound terminals 
again lowering into the MVFR range tonight 09-12z. 

KSEA...MVFR ceilings hang on this morning, before lifting around 
20z. Expect mid/high cloud deck to remain at least broken through 
the day, but sufficiently high. Southerly surface wind will become 
more west this afternoon at around 6-8 kt, before returning 
southerly tonight. Expect a return of MVFR stratus tonight after 
around 10z.

&&

.MARINE...Surface high pressure centered offshore through the end 
of the week will move closer to the coastal waters over the weekend. 
A weakening front will reach the waters Monday night. The small 
craft advisory for the coastal waters has been expanded to include 
the inner coastal waters as well given the continued steep seas. 
Expect seas to continue to remain around 7 to 9 ft with the dominant 
period around 7 or 8 seconds into Friday due to the persistent 
northwesterly winds maintaining these steep conditions. 

Elsewhere, expect diurnally driven pushes of west winds through the 
central and eastern Strait of Juan de Fuca each of the next few 
nights. Winds will generally be right around 20 kt each night with 
some gusts to 25 kt. Will maintain tonight's advisory for now and 
evaluate trends to determine the need for any additional advisories 
on subsequent evenings. 

&&

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

     Small Craft Advisory until 6 PM PDT Friday for Coastal Waters 
     From Cape Flattery To James Island 10 To 60 Nm-Coastal 
     Waters From Cape Flattery To James Island Out 10 Nm-Coastal 
     Waters From James Island To Point Grenville 10 To 60 Nm-
     Coastal Waters From James Island To Point Grenville Out 10 
     Nm-Coastal Waters From Point Grenville To Cape Shoalwater 
     10 To 60 Nm-Coastal Waters From Point Grenville To Cape 
     Shoalwater Out 10 Nm.

&&

$$