Are there regular cycles to tropical storm strength, and how does this affect your answer? (rogerpielkejr.blogspot.ru)
Low air pressure in the core — a measure of storm strength — bottomed out at 879 millibars, making Patricia, officially, the most powerful hurricane ever measured in the western hemisphere. (carbonbrief.org)
There is no scientific basis for thinking that an increasing storm strength trend would limit itself permanently to cat 4s, and as noted below a good basis for thinking otherwise. (realclimate.org)