Frank P wrote:
What I'd be more worried about, and perhaps something that is more likely again this season, is another repeat of the 2004 and 2005 seasons with a landfalling Cat 3 storm bringing in a Cat 5 surge..... Ivan had a pretty impressive surge in 2004 and Katrina was unprecedented.... so you don't have to have a Cat 5 at landfall, but being a Cat 5 and then weaking to a Cat 3 in the GOM as it approaches land is just as bad from a surge standpoint.... last two seasons proved that
Actually, the fact that both Katrina and Ivan were much stronger prior to landfall did not have that much of an effect on the eventual storm surge. I saw a talk by a surge expert at the NHC. He re-ran the surge calculations for Katrina and Ivan assuming they were the same intensity offshore as at landfall and the surge height difference was only a few feet. What makes a bigger difference than the SS categorhy is the Radius of Maximum winds and the extent of the stronger wind field. Remember, SS just looks at peak winds that could occur only in a TINY part of the hurricane. Just being a Cat 5 doesn't mean anything with respect to the potential surge. Have to look at the entire wind field.