The Fed is expected to announce a quarter-point interest rate hike when it wraps up its June meeting Wednesday afternoon, but that rate hike is widely anticipated and there are a few other things that could stir up markets more.

First, the Fed will issue a statement at 2 p.m., along with its latest economic forecasts and its interest rate outlook. Then Fed Chair Jerome Powell briefs the media at 2:30 p.m.

Markets will be hanging on any headlines that add to the debate about the course of Fed rate hikes. There is still a clear divide between those Fed watchers who expect another rate hike this year after Wednesday and those who expect two more. So if the Fed sounds more optimistic on the economy, raises its interest rate forecast, or even announces that Powell will hold press conferences after every meeting, any and all of those could be viewed as "hawkish."

The Fed releases its so-called dot plot, a chart with anonymous Fed officials' forecasts on interest rate expectations. The chart currently shows three rate hikes for this year, but it's a very close call based on the positioning of the dots, so any slight move could add an interest rate hike in December. That would be a clear message from the Fed that it is going to be more aggressive.

Read more in CNBC.