Heard (from somewhere deep in the bowels of the Katrina threads) that the storm took an unpredicted turn.
A puff of dry air from the Midwest hit Katrina and she took a turn as a result and then she resumed her originally projected path./
And that was completely, utterly wrong.
The NHC forecast landfall point (directly over New Orleans or a couple miles E of New Orleans) was essentially unchanged from 11PM Saturday night, through TEN more NHC forecast tracks, through landfall on Monday.
The storm ended up basically following this forecast track precisely.
The NWS was forcasting massive storm surges throughout Mississippi all day Saturday and all day Sunday. Mississippi was put under the same Hurricane Watches and Warnings as Louisiana.