I just found this out through the Reddit PAX East thread, but there will be an Overwatch Open tournament this week at PAX East in Boston.
It appears it will be streamed at http://www.twitch.tv/paxarena Saturday and Sunday. A schedule is here: https://www.twitch.tv/team/pax
There's not much info about details but I got some from these pages:
http://www.idigitaltimes.com/pax-east-2016-twitch-announces-plans-largest-pax-presence-date-528001
http://east.paxsite.com/schedule/panel/overwatch-open-registrations-for-the-overwatch-open-tournament
https://www.reddit.com/r/Overwatch/comments/4fa6bi/roverwatch_pax_east_qa_event_schedule/
If for some reason pros want to get into PAX East for bragging rights, you can procure PAX East tickets through craigslist and other usual channels