Along the west coast the concern would be morning fog, which might not burn off in time, especially with the Sun going away. In the midwest a concern is smoke from forest fires, since it's peak of summer drought and fire season. There's a risk no matter where you are, so just gotta plan and hope for the best. And it'll be awesome no matter what happens.

I really look forward to all the comments and recordings afterward. This will likely be the most photographed and filmed eclipse ever!