Hello Altar!  As far as I know, there is no Seattle area EA-focused charity evaluator.  Generally speaking, EA organizations do not engage in such work for a couple reasons.

1. EAs focus on impartial altruism, meaning that they try to give equal priority to everyone’s interests, regardless of their location.
2. The difference in impact between the least and most cost-effective organizations in Seattle is small relative to the difference in impact between the least and most cost-effective organizations globally.  This means that getting local-only donors to switch between local charities is significantly less valuable than getting people to switch from local to international charities.  It would have to be vastly easier to get local-only donors to switch for that work to end up being cost-effective.  More info here.

There have been some smaller efforts to do local priorities research from local or national groups.  Effective Altruism Israel ran their “Maximum Impact” program (details here and here).  This post discusses in more detail how local research is useful and links to a few other efforts in Singapore, Brazil, and the Philippines.

Sometimes local efforts from wealthier countries can identify globally cost-effective charities, particularly in cause areas besides global health, but I think another key reason they are created is to develop members’ evaluation skills, which can later be applied on a broader scale.  Local prioritization efforts in low income countries may also have success in identifying top global health organizations.

I hope this was helpful.  Let me know if you have any more questions!