(Radio Iowa) – It’s taken months, but the long-predicted La Nina weather pattern seems to have taken hold, impacting much of the nation’s climate — and the effects may linger through spring. After Iowa’s prolonged, bitter cold weather during most of February, climatologist and drought specialist Becky Bollinger says the March temperatures should follow a La Nina pattern and be warmer.

“Most of the country is showing a leaning towards more likely to have warmer-than-average conditions,” Bollinger says. The weekly U-S Drought Monitor shows wide sections of Iowa are abnormally dry, while much of western Iowa is under moderate to severe drought, with portions of northwest Iowa considered in extreme drought. Bollinger says the regions that are in drought now will likely stay that way.

“Areas that have been dry, unfortunately, have an enhanced chance of continuing to be drier than average into March,” she says. Bollinger says the outlook for March, April and May are likely to follow the same pattern. “We see most of the region showing increased chances of above-average temperatures through the spring,” she says. Bollinger says the climate outlooks predict the La Nina will fade to neutral conditions by summer.

A La Nina occurs when Pacific Ocean surface temperatures cool below normal, which then has a wide-ranging impact on North American weather.