No ballots may be counted until the polls close, in general. I believe they'll start on the advance votes at 8. The real question is how late the polls will close, because if you're in line at 8 pm they will allow you to vote (that has been the rule up to date!).
I would not be surprised if some polling places still have people queued up to vote at 10 or 11 pm, and the count cannot begin until they've voted or left.