Hurricane Post-Mortem

Nov 29, 2007 2:09pm

The 2007 hurricane season ends Friday night, and — what, you didn’t notice it?  Neither did most people in the U.S.  There was only one hurricane–Humberto, on the morning of September 13–that made landfall on the Texas-Louisiana border.  Otherwise, if you look at NOAA’s MAP of storm tracks for the year, most storms hit to the south, or stayed out in the Atlantic. And there slightly fewer of them than NOAA’s Climate Prediction Center had forecast, which has meteorologists there engaged in a bit of introspection.  Back in May they said there would likely be 13-17 named storms; there were 14.  They said there would probably be 7-10 hurricanes; there were six–a total that counts one storm that was reclassified upward after the fact. "The total numbers weren’t far off," said Gerry Bell, the lead forecaster there, when I talked to him on the phone, "but when you look at the number, duration, intensity–there, we were high.  So we’re going to do some investigating…figure out what climate factors we may have missed."  NOAA has an end-of-season summary HERE. Meanwhile, Eric Berger of the HOUSTON CHRONICLE reports on a small kerfuffle that’s broken out over whether the National Hurricane Center, in recent years, has been a little too fast "to designate several borderline systems as tropical storms."  (His piece is HERE, and he adds some detail in a blog post HERE.) Berger writes that as satellite monitoring and reconnaissance data have improved, storms that would have been ignored in past decades have now qualified as named storms.  That, according to some of the meteorologists he quotes, makes recent years look more active than they might otherwise have been.  He says insurance companies, using the totals to set their rates, are charging coastal dwellers higher premiums. He quotes Neil Frank, a former director of the hurricane center: "This year, I would put at least four storms in a very questionable category, and maybe even six."  Their winds were high enough to make them tropical storms, says Frank, but their central pressure, another measure of a storm’s strength, was too low. Dennis Feltgen of the hurricane center answers by e-mail, "every storm rating questioned…was justified using conventional methods, including Dvorak satellite estimates, and further supported by QuikSCAT in Chantal and Jerry, and reconnaissance aircraft data in Erin, Gabrielle and Ingrid."  He steers us to two storm-by-storm summaries–you can find them HERE and HERE.  "Surface pressure is not the true measure of a storm," he writes. Bell, at the Climate Prediction Center, says the seasonal outlooks are useful even if they were high.  "Even though we overpredicted, we alerted people," he said.  "Even when we miss, we perform a service."  (Satellite image above of Humberto from NOAA Environmental Visualization Program.)

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