Two active popups: Which will be shown?

I have to show every day another Advent-video in the popup. The popup of the new day has to be displayed at 0:00h in the night/start of the day. I planned this. But at this moment the popup of the day before is active too. Now I had the situation, that new visitors (with no cookie of the popup of the day before) get shown the old popup (advent day 1 instead of advent day 2). What can I do? I’d like to avoid stay awake till 0:00 to deactivate the old popup … ?? Thanks a lot for a help!!!