Is there a Notification Center widget to show more calendar information for tomorrow?
Just click on edit on the bottom of the Notification Center and add the "Calendar"-widget.

It shows me full day events and six hours from now on in day view...

EDIT: Just realized you are not using Sierra... let me check on that.

2nd EDIT: Checked it on my MacPro running El Capitan OS X 10.11.6, the widget exists in the same spot (and as a bigmouth that I am, until Sierra the OSes were called OS X, and from now on macOS... not that I could've read the number you gave us :D) 

3rd Edit: Oh and you did it even right when you asked originally, it was edited by a proactive moderator. Sorry for the wrong accusations. Now try it and mark it hopefully as resolved... :)