Thursday, May 17, 2007

Hurricane Season

Welcome to the 2007 Hurricane Season. Estimates I've seen predict a very active year, with 14-21 named storms including 7-9 hurricanes of which about half are expected to be category three to five, meaning winds exceeding 111 mph.

Here is a recent abstract from a paper published by a well respected lab:

Information obtained through March 2007 indicates that the 2007 Atlantic hurricane season will be much more active than the average 1950-2000 season. We estimate that 2007 will have about 9 hurricanes (average is 5.9), 17 named storms (average is 9.6), 85 named storm days (average is 49.1), 40 hurricane days (average is 24.5), 5 intense (Category 3-4-5) hurricanes (average is 2.3) and 11 intense hurricane days (average is 5.0). The probability of U.S. major hurricane landfall is estimated to be about 140 percent of the long-period average. We expect Atlantic basin Net Tropical Cyclone (NTC) activity in 2007 to be about 185 percent of the long-term average.

This early April forecast is based on a newly devised extended range statistical forecast procedure which utilizes 40 years of past global reanalysis data and is then tested on an additional 15 years of global reanalysis data. Analog predictors are also utilized. We have increased our forecast from our early December prediction due largely to the rapid dissipation of El Niño which has occurred over the past couple of months. Currently, neutral ENSO conditions are observed. We expect either neutral or weak-to-moderate La Niña conditions to be present during the upcoming hurricane season. Tropical and North Atlantic sea surface temperatures remain well above their long-period averages.

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