A shift away from this year's La Nina to El Nino could dramatically alter temperature and extreme weather patterns—and global warming may play a role.
Climate scientists are still trying to determine what role climate change plays in the La Niña/El Niño cycle. One study by scientists with NASA and the Pacific Marine Environmental Laboratory in Seattle suggests global warming may already be affecting the intensity and impacts of El Niño.
La Niñas also tend to exacerbate the tornado season. During early spring this year and during the spring of 2011, when La Niña was also holding court, an abnormally high number of tornadoes hit the U.S. midsection.
Whether El Niño develops big, small or not at all, the departure of La Niña should mean big changes in 2013 after a very unusual winter and spring in 2012.
Private meteorologists are under no such constraints. AccuWeather, a company based in Pennsylvania that does both short and long-term forecasts, released its prediction for the hurricane season last week. AccuWeather's forecasters envision a fairly typical year in the Atlantic.
- 10 named storms, four hurricanes and two major hurricanes
- 42 percent landfall probability anywhere in the U.S., compared with an average of 52 percent from 1981-2010
- 24 percent landfall probability on the East Coast, compared with an average of 31 percent
- 24 percent landfall probability on the Gulf Coast, compared with an average of 30 percent.