Philip Klotzbach, a research assistant at the Department of Atmospheric Science at Colorado State University, said at least 17 named storms, nine hurricanes and five major hurricanes with category three to five range are expected for 2007.
"When we issue our climate predictions, we look at the past and we know which seasons in the past were active seasons, and we know which seasons in the past were inactive seasons," Klotzbach explained.
"We try to go back and see what features were present in the atmosphere and the ocean before an active hurricane season in the past and which features were present in an inactive seasons in the past and basically see which features are present for this upcoming hurricane season."
Three predictors were selected which explained variability in the tropical Atlantic during the hurricane season using data from the period 1950 to 1990 and were tested on independent data over the past 15 years, he said.
Klotzbach said the combination of these predictors is able to explain about 50 percent of the variability in tropical cyclonic activity when the prediction is developed from data collected in February and March.
The probability of landfall for the U.S. coastline this year of a major category three to five hurricane is 74 percent compared to the long period average of 52 percent, according to Klotzbach.
For the Gulf Coast and the East Coast the probability of landfall is 50 percent compared to the long period average of 30 percent.
"We don’t issue specific landfall probabilities for the Caribbean, but in general when you’re predicting an active season, you have more storms in the tropical Atlantic. Therefore, your odds of getting major hurricane landfall in the Caribbean also increases," he said.
Klotzbach said meteorologists cannot predict where or when a storm is going to strike.
However, when they look at the past features that have an active Atlantic basin hurricane season, the odds of landfall go up, he explained, adding that this is due to the fact that there are more tropical cyclones in the open Atlantic, and the more storms there are, the more likelihood of landfall.
Even so, there can be an inactive year like 1992 which still had a major hurricane landfall, or years like the late 1990s which had active hurricane seasons, but not many landfalls, Klotzbach pointed out.
He noted that although 2006 was forecasted to be a very active year as well, the prediction did not come to bear. It was predicted early in the season that there would be an average of 17 named storms, nine hurricanes and five major hurricanes in 2006.
"Our seasonal forecast was certainly well above what actually occurred," he said. "The forecast that really busted was August. We thought August was going be an active month, but it wasn’t."
The forecast was lowered in August because El Nino-like features seemed to be appearing in the season, however meteorologists were surprised at the strength and swiftness in which the El Nino came, Klotzbach explained. El Nino tends to develop during the springtime and in the early months of the summer.
There was an average season in 2006 with 10 named storms, five hurricanes, and two major hurricanes, he said.
"Certainly, people living along the coastline think it was well below average because we had no land falling hurricanes last year, which is only the 11th time since 1945 that that has occurred," Klotzbach explained.
However, early in the season there were a few land falling storms and all of the hurricanes with the exception of Hurricane Ernesto, re-curved well out into the Atlantic Ocean, he said.
There tended to be a trough of low pressure along the East Coast, which Klotzbach said picked up the storms and steered them back out to sea before they could make U.S. landfall.
There were three tropical cyclones that made landfall last year – Alberto in the pan handle of Florida; Ernesto – first in Florida as a weak tropical storm and then in North Carolina where it did $400 million worth of damage, and Beryl which brushed Nantucket.
- Austin DWI - New York DWI