FXUS66 KSEW 031018

AFDSEW



Area Forecast Discussion

National Weather Service Seattle WA

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





&&



.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 late this morning. Ceilings mostly low end VFR in the

stratus deck with pockets of MVFR. MVFR stratus deck along the

coast 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...MVFR ceilings lifting to VFR 16z-18z. Stratus scattering

out around 19z with just high clouds into Friday morning.

Southwest wind 4 to 8 knots becoming northerly 22z-00z. Northerly

winds continuing into Friday morning. Felton





&&



.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. Felton



&&





.SEW WATCHES/WARNINGS/ADVISORIES...

WA...None.

PZ...Small Craft Advisory until 5 AM PDT early this morning for 

     Central U.S. Waters Strait Of Juan De Fuca-East Entrance 

     U.S. Waters Strait Of Juan De Fuca.



&&



$$