La Nina's Persistence May Mean Another Dry Summer

The cool La Nina waters in the eastern Pacific Ocean, believed to be related to the 1999 summer drought in the eastern United States, are forecast by the National Oceanic and Atmospheric Administration to strengthen and persist through spring and early summer, Newman says.

A westward and northern movement in drought conditions is expected through the coming summer, Newman says.

La Nina is more fickle than her brother, however, according to Ken Scheeringa, acting state climatologist in Purdue's agronomy department.

"La Nina events tend to be more difficult to recognize and trace than El Nino events," Scheeringa says. "La Ninas tend to be less strong than El Ninos and fluctuate in and out of existence more frequently."

Newman says that overall, La Ninas are associated with higher drought risks across the continental United States and Canada. "Drought is easily the No. 1 natural disaster in terms of its potential impact on food production and supply," he says.

A growing understanding of how ocean surface temperatures influence global weather has allowed modest success in predicting irregular weather events and seasonal weather trends, such as drought, Newman says.