Update in January 2021. There are still no visits planned for the nearby future. You have to fly to LA to file an application in person. You can also fly to Vancouver, BC, but you cannot currently drive there from Seattle.

To schedule a visit, use the online reservation system System Zdalnej Rejestracji (e-konsulat.gov.pl)

In spring 2020, the Consulate General of the Republic of Poland in Los Angeles suspended its program of rotating consular visits to different cities such as Seattle and Portland to handle passport applications for Polish citizens due to COVID-19.

More: the Consulate passport info