So around the eye of this intense hurricane is the eyewall, which is closed and solid. It can be seen on radar.
Within that eyewall are mesovortices---basically, and simply, and somewhat inaccurately, these are giant tornadoes.
NOAA and the Air Force have had planes in the storm continuously for some time now, and the NOAA plane this morning has consistently found these mesovortices have winds within them well over 160mph, just 1,000 feet above the surface. This doesn’t mean that Michael is a Category 5 (although the hurricane could still make a run at that before landfall), but it does mean that if the hurricane does not weaken, when the eye and eyewall come ashore, someone will see some truly intense and powerful---and destructive---gusts. That Michael’s eyewall, especially on the east, is full of these, is a sign that the storm is still intense and still getting stronger.
Mesovortices weren’t really discovered until Hurricane Andrew, where linear destruction patterns across south Dade County led to their discovery and observation.