Meteorologists at Colorado State University made a slight modification to their forecast for the rest of the 2013 Atlantic Basin hurricane season, but they still think three major hurricanes are likely to form before the season ends.
CSU forecasters Phil Klotzbach and William Gray had predicted four major hurricanes in the seasonal forecast they released in June. The updated forecast, released Friday, predicted that 18 named storms will form before the hurricane season ends November 30. That was the same number posted in the June forecast.
Gray and Klotzbach made a slight change in the number of hurricanes they think will form, lowering the number from nine to eight.
A tropical storm gets a name when its winds exceed 39 mph, and it becomes a hurricane if its winds reach 74 mph.
If a hurricane’s winds exceed 110 mph, it is considered a major storm capable of inflicting extensive damage if it makes landfall.
Four named storms have formed in the Atlantic Basin — which includes the Atlantic Ocean, Gulf of Mexico and Caribbean Sea — since June 1.
Hurricanes draw their energy from very warm ocean water. Klotzbach said he and Gray decided to modify their forecast because temperatures had changed slightly since June.
“While the tropical Atlantic remains warmer than normal, it has cooled somewhat in the eastern portion of the basin,” Klotzbach said in a prepared statement.
Klotzbach added that the forecasters think it unlikely that hurricane formation will be inhibited by the formation of a weather phenomenon known as El Niño. The phenomenon occurs when waters off the Pacific coast of South America become unusually warm.
When that happens, it can increase upper-level winds — known as wind shear — over the area of the Atlantic where hurricanes usually form and strengthen. The wind shear can disrupt hurricane formation and prevent storms from strengthening.
The forecasters still think a major hurricane is likely to make landfall somewhere on the U.S. coast from Texas to Maine. Eight years have passed since the last major hurricane came ashore in the U.S. That’s the longest period between major hurricane landfalls since record keeping started in 1851.
Klotzbach and Gray will continue updating their 2013 forecast every other Friday through October.
The full update from the CSU forecasters can be seen here.
Willie Drye has been writing about hurricanes and other topics for National Geographic News since 2003. Visit his blog, Drye Goods.