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Originally Posted by kmanrox
didnt they say similar stuff about gustav? (i dont know, just asking)
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Yes they did. They did and it turned out not to verify. This is the problem with probability based forecasts. Some verify, some don't. Katrina verified, Gustav didn't.
Every storm that threatens New Orleans sets off the same panic because of the nature of New Orleans itself. New Orleans presents unique problems in the US. Plenty of false alarms there for sure. Problem with NO is the entire city is below sea level and is surrounded by 300 miles of levies. No one knows when a levy will be overtopped or fail. Such an unpredictable thing.
One problem is that improvements in intensity forecasts have come much slower than in track forecast. The 3 day average error in track forecast is about 140 miles. In 1970 it was 460 miles. Since 1990 the average track error has decreased from 290 miles to 140 miles. The average 3 day error in forecasting intensity is virtually unchanged at 19 knots. Which is about 22 mph. There is a new model the NHC is using that is still being developed. It is going to use unprecedented modeling of the real structure of each storm including real time data from recon, buoys and so on. It is hoped that this will improve the intensity forecast.
The unusual character of Ivan is its size and the large area over which tropical storm and hurricane force winds exists. It's only a category 2 but it is estimated that nearly as much water has been put in motion as in Katrina. Only about 10% less.
I've been watching the local Texas news. There's already some street flooding in Texas and landfall is a long ways off.