Holding would be impossible to police, and I think we saw how poorly the PI review went a number of years ago. I think they could do quick looks for personal fouls and coaches challenges for a subset of penalties. The game is just too fast for the refs to keep up.
Contributing factors to DCA’s temps are primarily the river temperature and the overall DC heat island. The sensor isn’t that close to the runway.
The river temperature this morning was 58 degrees just upstream.