U.S. scientists say La Niña-controlled weather patterns have the potential to produce more severe storms, as those recently seen in the Midwest and South.
Assistant Purdue University Professor of Atmospheric Sciences and Agronomy Dev Niyogi, who is also Indiana's state climatologist, said La Niña is making climate predictions difficult.
"La Niña weakening should lead to a somewhat average spring season, both in terms of temperature and precipitation," Niyogi said. "However, that is deceptive because historically La Niña usually leads to wide swings in weather conditions.
"So, even if the average conditions would be somewhat normal, a La Niña spring is notorious for a rollercoaster weather pattern."
La Niña occurs in a natural cycle about every two to seven years when ocean waters in the Pacific equatorial region are cooler than normal, Niyogi said. The phenomenon is caused by the circulation and interaction of cold and warm ocean water.
The good side of severe storms, such as those occurring recently in the Midwest and South, is that they produce enough rain to overcome drought conditions, said Niyogi. The negative side is the potential for tornadoes, lightning and flash floods.
Copyright 2006 by United Press International
Explore further: Measuring the proper motion of a galaxy