I saw in my Priority Pass monthly update that Priority Pass members now have access to the Chesapeake Club Lounge at BWI. This is the same lounge that BA contracts for use by its Club World and elite passengers.
Judging by its location, I can't imagine the lounge is very large, so congestion could become at problem with this new access.
https://www.prioritypass.com/lounges...oungecode=BWI3