Here's what Seattle has going for it: One requirement is to have 25,000 hotels rooms no less than an hour away. King County has around 35,000 with some 5,000 more in development. That doesn't include Seattle's ports where cruise ships dock and could add thousands of additional rooms.
The average temperature is required to be at least 50 degrees if the stadium is not domed. But, remember that didn't stop the Meadowlands from hosting. Seattle is only a few degrees below that 50 degree average and isn't known for February snow.
There also have to be 70,000 seats at the facility. CenturyLink is just shy of that by about 3,000, but, as the Seattle Sports Commission's Ralph Morton puts it, "where we are short in some areas we can far exceed in others."
Seattle is a walkable city and that would undoubtedly be a major selling point. However, mass transit is also important. The light rail project connecting the University of Washington to the downtown core and the airport would need to be complete.
Work would also need to be completed on the replacement of the Alaskan Way Viaduct.
There is no official bid yet for 2019 and beyond. But, Seattle is positioning itself for that that possibility.