think she may be at cat 3 tonight, but i wouldn't expect her to make cat 4 until she hits the Loop Current full on.... yes its a little cooler, but i think that once she passes and goes through an ERC tomorrow, i think Cat 5 is not out of the question on thurs.... Katrina went through an ERC during the night as she moved over the loop current and that next morning she blew up..... i am tending to go with a cat 3 - 4 at landfall.... just sw of Houston. I think storm surge will be another BIG problem with this system, along the texas coast.

Here's some research on the Loop Current:
http://www.esl.lsu.edu/research/

Also for Reference, Here's what Katrina did:
http://katrina.esl.lsu.edu/katrina/images/g12.050824.25.sst2.comp.gif
(GOES SST/SSH Two Day Composite - Aug 24, 25)

Current WV of Rita
http://www.esl.lsu.edu/webpics/goes/Storm/4pnl/latest_wv_loop.gif