The 11am advisory from NHC quotes 166kt flight-level winds and a central pressure of 907 mb, with no gross structural signs of it weakening (though they say it should weaken, because "it can't stay this strong for very long". Wishful thinking is a bad forecasting tool.)
For comparison, Hurricane Camille had a central pressure of 908. Andrew, 922. Hurricane Gilbert, which had the highest wind speeds ever recorded in an Atlantic of Gulf hurricane, was 888. Actually, only Gilbert and two unnamed hurricanes have had lower recorded pressures than Katrina. Nasty B word-mother of a storm...