2017 Hurricane Season Forecast to be Slightly Less Active

An early forecast from scientists concluded that a weak or moderate El Niño is likely.

by Elizabeth Djinis, Sarasota Herald-Tribune, Fla. / April 7, 2017
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(TNS) — Here's some welcome news for most Floridians: The upcoming hurricane season could be slightly below average.

In fact, we could see as few as four hurricanes.

An early forecast from scientists at Colorado State University's (CSU) Tropical Meteorology Project concluded that a weak or moderate El Niño is likely by the height of the Atlantic hurricane season, along with cooling temperatures in the tropical Atlantic and the North Atlantic Ocean. An El Niño weather pattern generally results in fewer hurricanes in the Atlantic basin, as it increases wind shear — strong winds that can break up hurricanes as they're forming.

These factors prompted scientists to forecast 11 named storms — four of them intensifying into hurricanes, including two that are major hurricanes with winds topping 110 mph.

"If you have El Niño, it kind of drives the bus," said Philip Klotzbach, the co-author on the report. "If you don't have El Niño, then you have to start looking at other factors."

Still, Klotzbach warned that an El Niño pattern is not a guarantee that Floridians will emerge from the hurricane season unscathed. In fact, Category 5 Hurricane Andrew struck in an El Niño year, which Klotzbach said partially occurred because the storm began in the deep tropics.

"You can still certainly have a major hurricane in the deep tropics in an El Niño year, but odds are reduced," Klotzbach said.

On average, there are 12 named storms, defined as systems with sustained winds between 39 mph and 73 mph, with 6.5 of of them becoming hurricanes, two of them major, meaning a Category 3, 4 or 5 storm.

There is a 42 percent probability of at least one major hurricane making landfall on the U.S. coast this season, compared with the average of 52 percent. But there is a 24 percent chance of a major hurricane hitting the Gulf Coast, 6 percent more than the last century's average of 30 percent, according to the report.

Although experts always caution that early forecasts can turn out to be inaccurate, the CSU report, co-penned this year by Klotzbach and Michael Bell in the school's Atmospheric Science Department, has a fairly high correct-early-prediction rate of 80 percent: 28 out of 35 of the anticipated below- or above-average seasons have developed as predicted, the report said.

The private weather forecasting service AccuWeather released its early forecast Wednesday and also predicted a below-average season with slightly differing numbers, anticipating 10 named storms, five hurricanes and three major hurricanes. AccuWeather factored the El Niño into those reports, combined with warmer temperatures in the Pacific Ocean.

Last year's hurricane season ended the record 10-year period without a hurricane making landfall in Florida, with Hurricane Hermine striking north Florida in early September. Hurricane Matthew didn't land in Florida, but caused significant damage as it skirted the state's east coast in early October. In total, 2016 saw 15 named storms, including seven hurricanes, three of them major.

Matthew and Hermine also caused considerable economic damage for the state at around $1.6 billion, reported in December 2016. That amount was the highest for natural disasters since the 2004 and 2005 hurricane seasons, according to Division of Energy Management Director Bryan Koon.

Last year was fairly consistent, if a little bit higher, with Klotzbach's predictions for the season. The early 2016 forecast projected 12 named storms, five of which would be hurricanes. Of those five, two would be major storms. He also noted a 50 percent chance of a major hurricane hitting the U.S. coast.

Hurricane season begins June 1 and continues through Nov. 30. The months of August, September and October generally see the highest hurricane activity.

Despite the below-average prediction, experts urged residents to remember that even a single hurricane can have a large impact.

"It takes only one storm near you to make this an active season," Bell said in a press release.

Federal forecasters will issue their prediction for the coming season next month.

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