The only glimmer of good news this morning is that Isaac is still strengthening very slowly. Although an eye is evident on the satellite - and in the radar aboard the NOAA research aircraft - the winds are not increasing dramatically in the huge sprawling circulation. Still, steady strengthening is likely as the center heads toward the Louisiana or Mississippi coast. The NHC is now forecasting Isaac to be a Cat. 1 at landfall, though a Cat 2 certainly can't be ruled out. (The NHC gives it a 5% probability of reaching Cat 3.) Huge circulations take longer to spin up, and this one doesn't have a lot of time.
The nightmare scenario of a long-duration landfall I wrote about last night continues. The forecast consensus is that the storm will slow to a crawl near southeastern Louisiana keeping southeast to east winds into the corner between Louisiana and Mississippi, and southerly winds against southern Alabama and the western Florida Panhandle, for an EXTENDED period of time. This will continue to push Gulf water over the coast and into Mobile Bay and other inlets for longer than normal in a landfalling hurricane.
New Orleans has decided NOT to order an evacuation, trusting the new levees. It's important to remember, however, this storm could well put much worse weather over New Orleans than Katrina. If you recall, dry air was filtering into the left side of Katrina when it made landfall. There was very little damage from wind in the city. Top readings were mostly of tropical storm strength, except on the far east side. Issac may put higher winds over the city proper meaning people will have to take precautions in their homes that were not required in Katrina.
Other areas outside the massive new levee system WILL require evacuations, however. It's extremely important that people take action today to get to a safe, comfortable place with plans and supplies to ride out a relentless attack of wind, rain, and high water from Isaac.
See you on The Weather Channel.