Forecasters from Colorado State University are predicting a "well below-average" Atlantic hurricane season for 2015. The forecast calls for seven tropical storms, of which three will become hurricanes and one will become a major hurricane.
In an average year there are 12 tropical storms, of which seven will become hurricanes. A tropical storm has sustained winds of 39 mph; it becomes a hurricane when its winds reach 74 mph.
The forecast was released on Thursday by meteorologists Philip Klotzbach and William Gray of Colorado State University's Tropical Meteorology Project. The Atlantic hurricane season runs from June 1 to November 30.
"The tropical Atlantic has anomalously cooled over the past several months, and the chances of a moderate to strong El Niño event this summer and fall appear to be quite high," Klotzbach said in a statement. "Historical data indicate fewer storms form in these conditions."
An El Niño event (when the water in the eastern pacific near Panama and Peru is warmer than usual) is associated with a corresponding increase in wind shear in the Caribbean Sea; and wind shear inhibits the formation and strengthening of Atlantic hurricanes.
If the forecast is accurate, it would be the second straight below-average season. The 2014 Atlantic hurricane season had eight named tropical storms.
Although Klotzbach and Gray "anticipate that the 2015 Atlantic basin hurricane season will be one of the least active seasons since the middle of the 20th century," they still cautioned that "it only takes one hurricane making landfall to make it an active season" and they encouraged coastal residents to "prepare the same for every season, regardless of how my much activity is predicted."
The first named storms of the 2015 Atlantic hurricane season will be Ana, Bill, Claudette and Danny.