Wunderground.com, which I in general consider as pretty accuate, give 80% rain for Monday night, changing into 40% for Tuesday during the day.
Not too good. Guess it comes down to tuesday morning, to see how it is.

If you come by car, just enter through the front side of the track, tell them you come for the track day and basically they will let you in.
You can then drive all the way to the back side of the pits, and find the garage we are in.