A satellite view of Hurricane Irene on Tuesday, Aug. 23, 2011. (NOAA/NASA)
WASHINGTON -- The federal government is predicting an near-normal hurricane season in the Atlantic this year, with anywhere from four to eight hurricanes forecast to form.
A typical season, based on the years 1981-2010, sees six hurricanes.
The Atlantic season runs from June 1 to November 30. This forecast from the National Oceanic and Atmospheric Administration (NOAA) covers any storms that form in theAtlantic Ocean, the Caribbean Sea and the Gulf of Mexico.
Overall, nine to 15 named tropical storms are forecast to form. Tropical storms have top wind speeds of 39 mph or higher. Once a storm's winds reach 74 mph, it becomes a hurricane.
According to NOAA, two current climate factors will limit hurricane development, if they persist: strong wind shear, which can tear apart burgeoning hurricanes, and cooler sea-surface temperatures in the far eastern Atlantic.
"Another potentially competing climate factor would be El Niño, if it develops by late summer to early fall," says Gerry Bell, lead seasonal hurricane forecaster at NOAA's Climate Prediction Center.
El Nino is a warming of tropical Pacific ocean water.
"In that case, conditions could be less conducive for hurricane formation and intensification during the peak months (August-October) of the season, possibly shifting the activity toward the lower end of the predicted range," he says.
Two of the biggest private weather forecasting companies, AccuWeather and the Weather Channel, also predicted average or slightly below-average hurricane season earlier this month. AccuWeather's said 12 named tropical storms will form, five of them hurricanes; the Weather Channel forecasts 11 tropical storms - of which six will be hurricanes.
Last month, the meteorologists at Colorado State University estimated 10 tropical storms and four hurricanes.
Since 2000, NOAA's hurricane forecasts have been more right than wrong, but not by much: NOAA's prediction has been accurate in seven out of the past 12 years, according to a USA TODAY analysis.
NOAA's prediction was too low in four years and too high in just one year: 2006. Ten of the 12 years have seen above-average activity for tropical storms and hurricanes.