FWIW here is the extended forecast for Grand Blanc (Mount Holly). Almost every night is cold enough to blow. Starting the 15th there is a good 8-day stretch of very low overnight temps as long as some of that rain either fails to materialize, or turns in to snow, instead, we might be in good shape.
They need 28F and low humidity to blow. But once they can start doing that, it's amazing how quickly they are capable of opening a few runs. Less than a week if conditions are good. I think last year they opened on like 4 or 5 days notice.