The 12Z SHIPS intensity model goes berserk with Rita, bringing it up to 125 knots (145 mph, strong cat 4) in 48 hours, before slowly weakening it prior to landfall (forecast landfall is between 72 and 96 hours):

http://www.srh.noaa.gov/productview.php?pil=WBCCHGHUR (click on the "Previous Version" link on that page if you don't see the output for Rita right away)

That is quite a change from the previous SHIPS runs which kept the max intensity around 100 knots. I imagine the much higher initial intensity for the latest run played a role in the intensity jump.