why not "tomorrow is Friday", that is the normal way to say this in the US. And of course when Friday finally arrives it is good to know the famous acronym "TGIF" Thank God is Friday!
This isn't saying that tomorrow is Friday or the day after the current day is Friday. What it's referring to is the next day that something happens will be on Friday. Like когда будет следующий концерт? Следующий день - пятница! Or something around that.