well, i don't think it'll hit quite as strong as it is, either. but the thing is, this isn't a small hurricane where the concentric eyewall cycles are in play. katrina's appearance is annular.. in that it has a large eye and single convective ring. usually these don't fluctuate or cycle, but slowly spin down. thing is, the environmental conditions aren't forecast to deteriorate.. if anything the waters along its terminal track are slightly warmer.. than they were out in the central gulf.
it may spin down to a 4, but it'll have to start soon... ivan was a similar case and it took two days to get from a five to a strong 3 and there was cooler water and some shear coming into play. i'm not saying that something similar won't happen.. it should just start happening too late to make much of a difference.
landfall intensity will probably be 130-140kt.
HF 2040z28august