Lower Queen Anne/Seattle Center area traffic will be impacted by Microsoft’s Annual Company Meeting tomorrow, Thursday, September 13.

15,000 people are expected to attend the meeting at Key Arena according to SDOT, arriving via 200 charter buses and 4,000 cars.  The meeting is scheduled to run from 10am to 3:30 p.m, with attendees arriving at the as early as 8:30am.

Expect “heavy congestion” in the morning and late afternoon between the I-5 Mercer off-ramp and the Seattle Center and on surrounding streets. Add in the recent Mercer re-routing that has resulted in many instances of gridlock in South Lake Union, and it’ll be a traffic nightmare.