Dec 072009
Authors: Kirsten Silveira

With today marking the end of the Atlantic Ocean’s hurricane season, CSU’s Atmospheric Science Department missed its seasonal hurricane prediction by only one storm.

Nine named storms developed in the Atlantic this season — the season lasts from June 1 to Nov. 30 annually —, one less than the CSU team’s projection of 10 named storms and significantly more than the annual average of 5.9. No storms made landfall on the U.S. mainland.

Statistics recorded from 1950 to 2000 show that of those 5.9 storms, on average 3.6 make landfall, only 1.9 of those storms actually have enough force to be a hurricane, CSU atmospheric science researcher and co-author of the forecast Phil Klotzbach said.

“You can have years like this one where none touch land,” Klotzbach said.

Bill Gray, an atmospheric science professor and meteorologist, came to CSU in 1961 and released his first hurricane forecast in 1984. Twenty-six years later, Gray is still making predictions alongside Klotzbach.

“We can’t tell for sure all the storms that will show up,” Gray said, adding that, during his career, the worst year for hurricanes was 2005 when Hurricane Katrina and Wilma hit the United States.

The development of a hurricane or tropical storm is based on a set of climate features that Klotzbach said seem to be nearly identical in years when his team predicts a large number of hurricanes in the Atlantic.

These features include water temperature, wind speed and atmospheric pressure.

“We basically use the past to predict the future,” Klotzbach said. The team uses Microsoft Excel to map out statistical data from the previous years and make its annual predictions, he said.

To the tell-all climate signs, Klotzbach and Gray base the majority of their predictions on, he said, the presence of El Niño, a warm current in the Pacific that flows along the equator, is another factor.

“When we had El Niño in the Pacific, there were less hurricanes in the Atlantic,” Klotzbach said.

Hurricanes are assigned an intensity level from category one, a mild storm, to category five, a devastating storm. The most recent storm to be labeled a category five was Hurricane Andrew, which destroyed South Florida in 1992.

The World Meteorological Organization, Klotzbach said, is in charge of naming all the hurricanes and said unless a storm leaves a “tremendous” amount of damage in its wake, its name will be used again every six years.

The team has begun compiling all its statistics for next season’s prediction, which it will be released in December. Before a season, Klotzbach said his team has a general idea of whether it will be “active, inactive or average,” but said when predicting there is a large amount of uncertainty.

“It’s different than predicting the weather for tomorrow,” he said.

 Posted by at 3:15 am

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