Emergency Managers: Annual Hurricane Season Predictions are Bunk

By Joseph Straw

Reporter Allen G. Breed and colleagues at the Associated Press marked Sunday's start of the 2008 hurricane season with a neat look at the annual crop of expert predictions for the number and severity of the year's storms. The forecasts are often way off.

Climatologist William Gray of Colorado State University's (CSU) Tropical Meteorology Project has issued forecasts annually since 1984. He is now joined by the U.S. National Oceanic and Atmospheric Administration (NOAA), London's Tropical Storm Risk Consortium (TSR), and North Carolina State University's (NC State) Coastal Fluid Dynamics Laboratory.

Gray's predictions receive the most publicity, and the widest skepticism.

In 2005, Gray and his collaborator at CSU, Phil Klotzbach, predicted 15 named storms, including eight hurricanes.  There were instead 28 and 15, respectively, one of them Hurricane Katrina.  The next year CSU heightened anxiety by predicting 17 named storms and nine hurricanes, there were instead 10 and five, respectively.

An AP poll of state emergency managers from Maine to Florida found consensus: the predictions, and their press coverage, are useful in raising public hurricane awareness and preparedness, but little else.

The AP, however, aknowledged the fine print.  From the start, Gray has only claimed to predict "50 percent of the total variability" in annual storm activity. NC State issues its own number predictions, but with probabilities, typically in the area of 10 percent for each storm.

The experts blame the media, and some public officials, for an alarmist, headline mentality that omits the forecasters' caveats.

Based primarily on the same historical data, the predictions—including this year's—typically fall in the same ballpark.

For 2008, NOAA predicts a 65 percent chance of between 12 and 16 named storms, six to nine of them hurricanes. NC State predicts 13 to 15 named storms, including six to eight hurricanes. CSU predicts 15 named storms and eight hurricanes. TSR predicts the same, plus-or-minus four named storms and three hurricanes. 


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