It's been a while, but is it definite that they move the car on the day of the storm in the first one? Marty1 is there for what, a week?
Yes, the DeLorean is in Doc's garage for that whole week. When Lorraine comes to ask Marty to the dance, they had to cover it up with a blanket.
Marty and Doc don't come back to 1955 from the alternate 1985 until November 12th, a week after Marty had already came back the first time.