Indeed there was traffic tie-ups almost all day in Morelia Thursday. That was what our taxista told us and what we were experiencing as we were going to comida China that day. It was predicted to last up until 2pm which was about correct. We had experienced gnarly traffic going into Av Universidad where we were scheduled to have lunch at Wang Jiao's at 2pm. The traffic was OK again, well... normal, after we left the restaurant.
Good thing you didn't come Thursday from Pátzcuaro area, traffic was whacked. Missed a good lunch though.