You mean it is different from it's normal Mouse on Crack meandering? LOL
Seriously, the divergence you are starting to see in some of the models is indicitive of what some have been talking about with Rita possibly stalling at some point. The steering mechanisms that the models all count on and calculate off of are dissappearing with Rita. SO, as a result the models are - to put it simply - getting confused.
With nothing to really steer her, Rita is basically going to go on the path of least resistance, she will follow whatever weakness she can find, and she will also follow the warm water. Basically, since there is nothing to move her, she will just keep plowing along in the direction she is heading.
As convection ebbs and flows, she will wobble in the direction of the strongest convection (right now that is the west side of the storm). This is why a lot of Mets (Bastardi/Cosgrove/etc) are bringing Galveston/Houston back intot he MIx -- Rita is wobbling that way, the warmest water is that way, and as the ridge retreats the weakness is that way.
If what you are saying is true, she is currently headed directly for Port Lavaca, Victoria, and San Antonio. That puts roughly Mobile Alabama/Katrina style surge into Galveston Bay.