"This storm was "predictable," but only about 24-36 hours before it hit."

There's predictable in the sense of being able to say exactly where it was going to hit and how bad it was going to be, and what Poppagator said there was clearly true, at least in terms of what people had been told.

But there's also predictable in the sense of it being known that Category Five hit the US mainland every few years - and that the levees had not been built to an adequate standard to deal with a storm of that magnitude. And that adequate evacuation procedures and facilities had not been prepared in advance in case one of those Category Five hurricanes came to New Orleans, with its particular low-lying problems.