The 18Z GFS is even further to the right than the 12Z run, as it only brings Katrina to the coast and then basically skirts the coast all the way up to NC and then out to sea. This seems unrealistic.

The 18Z GFDL is pretty similar to the 12Z run, though more aggressive if anything. It still predicts doom for the Keys. This also seems somewhat unrealistic as it requires a pretty substantial southward jog at some point.

It'll be interesting to see what the other runs show, though I suspect the 00Z runs will have a somewhat better handle on the center of the system at the initial time.