The calendar is able to show advance warnings for upcoming events for any type of calendar event.
To set the advance notification period, head to Settings > Users > Select the User > Advance Notification of Calendar Events:
Use the drop-downs to select a value that will show a notification on the calendar of an upcoming event of that type.
Any event under that type will now show on the Calendar prior to when the event is due. The upcoming item will be seen in a white box with a dashed outline.