Tuesday, October 17, 2006

What Hurricane Season?

It was unanimous.

There was no disagreement.

The top experts in the hurricane prediction business all agreed: the 2006 season was going to be another incredible year.

Dr. William Gray and his young protégée, Philip Klozbach, forecast 17 named storms would form this year, the most storms ever predicted in the 22-year history of the Colorado State University program.

Meteorologists at NOAA and the National Hurricane Center agreed, predicting 13 to 16 storms. Adding that the “potential for hurricanes striking the United States is high.”

NASA hurricane expert Dr. David Adamec said conditions in the Atlantic Ocean were “hurricane friendly”.

Yet with two months to go, the 2006 hurricane season, especially in comparison to the last two years, has been a walk in the park. There have been nine named storms this year with five becoming hurricanes and three intensifying into major hurricanes.

Two of the most powerful storms this season (Gordon and Helene) were fish storms sliding through the middle of the Atlantic Ocean. The season’s other major storm, Gordon, made a direct impact on Bermuda knocking out power to more than half of the island residents but causing no serious damage.

The only storm to impact South Florida was wimpy Ernesto, a tropical storm that swept across the state just over month ago. The storm made landfall in mainland Monroe County on August 30 with winds of 45 mph. Compared to Frances, Jeanne and Wilma, Tropical Storm Ernesto was little more than a few dark clouds and a spit of rain.

So, what happened? How could so many incredibly smart people be so wrong?

Scientists say four unforeseen weather factors have contributed to this year’s relatively quiet year: increased wind shear, an abundance of dry air, the location of the Bermuda High and an increase in troughs along the east coast of the United States.

Wind shear (gusty winds at different levels of the atmosphere) was and continues to be a common feature this hurricane season. Throughout the year, upper level low-pressure systems rotated through the tropical breeding grounds of the Atlantic Basin ripping apart any tropical system that was trying to form.

On many occasions, those upper lows were accompanied by vast areas of dry air (often full of Saharan dust) making it more difficult for a tropical system to take shape. And, even if a storm did develop, it had a tough time intensifying in such a hostile environment.

The Bermuda High, a large high-pressure system often located over the island of Bermuda during the peak of the hurricane season, was instead much further east this year. That meant that any storm that did form was steered into the open waters of the Atlantic Ocean, well away from the east coast of the United States.

Finally, in recent weeks, a series of troughs of low pressure have formed along the east coast of the country blocking any tropical system from approaching the United States.

Still, the hurricane season is far from over. October is historically a fairly active month (Wilma hit on October 24) and tropical systems can still form during November. But, it is safe to say that the predictions made by all of the experts back in May and early June will not pan out. This hurricane season will bear no resemblance to last year’s incredible season.

Posted at 12:00 PM