(Updates with Pacific depression forming in seventh paragraph.)
June 2 (Bloomberg) -- Colorado State University increased the number of storms it expects to develop during the Atlantic hurricane season to 10 from nine.
The forecast calls for four of those to become hurricanes, one of them a major system, said Phil Klotzbach, lead author of the outlook. In April, his team predicted three hurricanes, with one growing into a major storm.
“We raised the number slightly because El Nino isn’t coming on as strong as we thought,” Klotzbach said by telephone today. “We’re still pretty confident it will be a quiet season.”
Atlantic hurricanes can disrupt U.S. and Mexican natural gas and oil production and affect refineries and agriculture. An estimated $10.6 trillion of insured coastal property in 18 states from Maine to Texas is vulnerable to storm strikes, according to the Insurance Information Institute in New York.
The 30-year average is for the Atlantic to produce 12 storms during the season that runs from June 1 to Nov. 30. An area of disturbed weather in the Bay of Campeche, in the southern Gulf of Mexico, that was given a 10 percent chance of becoming the season’s first storm was dropped today from the U.S. National Hurricane Center’s map.
The Gulf accounts for about 4.5 percent of U.S. natural gas output, 17 percent of oil production and 51 percent of refining capacity, according to the Energy Information Administration, the Energy Department’s statistical arm. Florida is the largest producer of oranges behind Brazil.
Forecasters are also monitoring a tropical depression in the eastern Pacific that’s expected to become that region’s second storm since its season began May 15.
In April, forecasters believed a powerful El Nino, a warming of the Pacific Ocean, would develop and disrupt weather patterns across the Atlantic, making it harder for tropical systems to form there, Klotzbach said.
In addition, sea surface temperatures across the Atlantic were cooler than in past years, also an indication fewer storms may form, he said. While that basin has gotten warmer, it still lags behind past years.
The Colorado State outlook is closely watched because its Tropical Meteorology Project team pioneered long-range hurricane forecasting 31 years ago.
The U.S. National Oceanic and Atmospheric Administration on May 22 predicted eight to 13 named Atlantic storms, with three to six of them expected to become hurricanes. A storm gets a name when its winds reach 39 miles (63 kilometers) per hour.
Klotzbach said the forecast for fewer storms than average shouldn’t change the way people prepare for hurricane season.
“You have to prepare the same for every season because you never know what is going to happen,” Klotzbach said. “There are plenty of years where relatively quiet seasons had severe impacts.”