The level of setting in a story that's the most realistic is literal. If you are talking about something in a literal manner, it means that you are writing about what is going on exactly around you or in a novel. So, what you write is indeed happening. If something is supernatural, it cannot be realistic. Foreshadowing is a technique which authors use to hint at what is going to happen in the future, so it's not really realistic as it doesn't happen in real life.