Now La Nina, and hurricanes
The National Oceanic and Atmospheric Administration says rapidly cooling surface waters in the eastern and central tropical Pacific are signaling the approach of another La Nina event. And with La Nina comes an increased likelihood of Atlantic hurricanes during the coming season. Read more here.
One reason the 2006 hurricane season fizzled was the unexpected arrival of an El Nino event - a warming of the Central and Eastern tropical Pacific. El Ninos tend to suppress Atlantic hurricanes by creating wind shear that decapitates the storms before they get well organized. Other factors, including dust blowing out over the Atlantic from Africa, also kept the hurricane count low last summer. (El Ninos have other impacts around the world, including drought and wildfires in Indonesia.)
La Ninas suppress hurricanes in the Pacific, but do the opposite for the Atlantic basin. Again, other factors come into play, too. But La Nina may be one that contributes to this year's storm count. Famed hurricane forecaster William Gray was predicting a more active 2007 storm season even before conditions began edging toward a new La Nina. Here's his forecast, issued in December. It includes the increased probabilities for East Coast landfalls in 2007.