For one thing, categorization of hurricanes as cat 5, cat 4, etc. is rather gross. If Michael had measured about two mph faster, it would have been a cat 5. We need decimal gradations, much as climbers accomplished by characterizing climbing difficulties by designating fifth class climbs (those in which the leader places some sort of protection in the rock) as 5.1 (minimal) to 5.9 (really hard, at least in the old days).

Similarly, one could talk about a 4.1 hurricane, as opposed to a 4.9, which Michael would have been. Again, it is really much more than wind, and many of these variables (velocity of the storm, path taken by the storm)) are rather hard to predict. One would be prudent to be somewhat pessimistic and plan for the worst while hoping for the best.