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FXUS66 KSEW 160400

AFDSEW



Area Forecast Discussion

National Weather Service Seattle WA

900 PM PDT Thu May 15 2025



.SYNOPSIS...Cool, cloudy and a chance of rain through Friday as a

frontal system moves in. An unsettled weather pattern will remain

in place across the Pacific Northwest this weekend through early 

next week, maintaining widespread clouds and rain showers.



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.SHORT TERM /TONIGHT THROUGH SUNDAY/...The forecast remains

largely on track this evening. Radar shows widespread light 

precipitation moving across the region tonight, with rainfall 

accumulations generally less than 0.10 inch expected. The previous

discussion follows below, with some minor updates made to the 

aviation section. 14



Moist, westerly onshore flow continues on Friday for cloudy and 

cooler conditions. Forecast highs are only in the 50s or similar 

to today. Rainfall is mostly along the coast with 

isolated/scattered coverage inland.



The weekend weather is wet and unsettled as a trough and trailing

upper low slide through. The air mass is slightly unstable on 

Saturday with a chance of afternoon/evening thunderstorms (mainly 

near the Cascades). Snow levels are low on Sunday, around 

3500-4000 ft, and may see light snow in the mountains (inch or 

less). 33



.LONG TERM /MONDAY THROUGH THURSDAY/...A ridge moves inland late

Sunday and early Monday for a brief break in the weather. 

Temperatures rebound slightly with highs in the lower 60s. A

quick-moving front clips through western WA later Monday for more

showers and windy conditions, especially along the coast. Onshore

flow prevails moving forward, leading to cloudy conditions and

near to slightly cooler than normal temperatures. 33



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.AVIATION...West to northwest flow aloft will continue as a weak 

upper trough and associated frontal system push across Western 

Washington. Ceilings will lower to MVFR in light rain at times this 

evening then persist across the region overnight into much of Friday 

as the system moves onshore. 



KSEA...VFR ceilings will lower to primarily MVFR in scattered 

showers this evening. These conditions will then persist overnight 

and continue through much of Friday. Surface winds S/SW 7 to 10 

knots. 



27/McMillian



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.MARINE...A weak frontal system will approach the area then 

dissipate as it moves onshore on Friday. Surface ridging will 

rebuild offshore on Saturday then shift into the coastal waters 

early next week. This will lead to increasing onshore flow and 

likely headlines for the coastal waters and strait. Another frontal 

system looks to move through the area on Monday. Seas will generally 

remain under 10 feet through the forecast period.   27



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.SEW WATCHES/WARNINGS/ADVISORIES...

WA...None.

PZ...None.

&&



$$