It was only recently that Andrew was reclassified as a cat 5.
I don't want to go too far off-topic, but I have heard rumors that the Insurance Industry and Florida politicians looking to try and keep insurance rates in the state under control had a LOT to do with the posthumous upgrade.
As a member of the best track supervisory committee that had to approve the upgrade, I can say that no politicians or insurance industry people pressured me (or anyone else that I know of) to upgrade Andrew.
The intensity of Andrew has been a hot topic ever since it made landfall. There have been people who have suspected it was a Category 5 ever since we were able to pin down the landfall central pressure at 922 mb. However, it took the advent of the GPS sondes in the eywall to let us go back and re-evaluate the available aircraft data to determine it was likely a Category 5.
That's wasn't all we looked at, though. We also looked at radar cell tracking in the eywall, and looked in great and gory detail at the observations from Fowey Rocks. My own studies of the Fowey Rocks obs compared to the radar position of the eyewall suggest that the last observation was taken somewhere outside the radius of maximum winds, and that it was anywhere from 5 to 30 minutes before the maximum winds reached the station. Since the last ob showed the winds had increased almost 20 kt in the 10 minutes prior to the failure, you can see that the peak winds could have been significantly higher that what was measured. Unfortunately, we'll never know for sure.
Even now, the debate continues as to Andrew's landfall intensity, as a scientist at the Hurricane Research Division is arguing based on boundary layer premises that it was a Category 4. Hopefully we'll eventually get enough data about what happens to a hurricane's surface windfield at landfall to find out whether he's right or not.
More information on the Andrew upgrade is available at
http://www.aoml.noaa.gov/hrd/hurdat/andrew.html
To bring this back to Ivan, I should point out that the three closest stations east of where the center came ashore are the Pensacola Naval Air Station, the Pensacola Airport, and the Pensacola National Ocean Service station. All of them stopped reporting before the worst of the conditions arrived. One of the DOW's was at the Gulf Shores airport and has reported gusts of 105-110 mph. However, that airport is several miles inland and it uncertain whether the strongest winds Ivan had to offer went over it or somewhere further east. At the very least, the wind gusts at the open coast would be higher that that.
Several portable mesonet stations and chasers were in the landfall area, so when their data comes in we should get a better picture of the landfall winds.
As for buoy 42040, I saw something similar in Hurricane Floyd back in 1999. Floyd ran right over a buoy east of Cape Canaveral, which reported a 938 mb pressure, 70 kt sustained winds and 54 ft seas. Although no one at the National Data Buoy Center can tell me for sure, I suspect that the smaller buoys (the 3 and 5 meter types) measure too low of winds in such seas.
There's a lot of work to be done before we make a final determination of Ivan's landfall intensity. Stay tuned, folks!
Jack Beven
Tropical Prediction Center
