We have not yet confirmed the location of his appearance. While he might stop by the Patty Murray campaign offices across I-5 on Mercer Street, that building falls outside the East Precinct's bounds (marked by the red box in the attached map).
Earlier this week, the president announced a last minute change for his itinerary for his Seattle visit. He'll skip a downtown meeting of insurance industry bigwigs and, instead, will attend an event where White House staffers say he will "talk about strengthening the economy and creating jobs for the families and businesses of Washington State" at an appearance with Senator Murray as the August primary votes are readied for tally for her run for re-election.
There is also the promise of a lunch with Obama so maybe include Oddfellows Cafe or Rancho Bravo in the president's stop list for the day.
Another possible -- but unlikely -- stop could be 13th Ave. Obama briefly lived on Capitol Hill as an infant in 1961 while his mother attended classes at the University of Washington. Some of the "birther" conspiracy theorists say that period of Obama's life is a fiction, by the way. But we've met a woman who can prove she was there in '61 and says she was baby Barack's babysitter. We'll take her word for it.
More likely is a public building like Garfield High's Quincy Jones Auditorium or a large institution like Seattle University.