Shift to La Nina could bring Iowa warmer, drier weather this fall
April 23rd, 2020 by Ric Hanson
(Radio Iowa) — Iowa’s weather may be in for a big change in the coming months as indications show a possible shift toward a La Nina pattern, which means hotter, drier weather. Meteorologist Dennis Todey, director of the U-S-D-A’s Midwest Climate Hub — based in Ames, says Pacific Ocean climate factors have been steady for the past couple of years but there are hints that may be changing. “We have been neutral to maybe hedging close to an El Nino,” Todey says. “We didn’t quite reach the category but we were close towards that side. It’s really interesting now, as you look ahead into the summertime, there are a few models that took us rapidly toward La Nina territory by the end of the growing season.”
Todey says there is an indication from computerized weather forecasting models of changes later this year. “The chances for La Nina start popping up in the fall, so it’s after the main part of the growing season here,” Todey says. “We do have to watch in case things would shift more quickly to La Nina than we’d expect, but right now the expectation is that we don’t get to La Nina territory during the growing season enough to be an issue.” Todey says sea surface temperature changes have an impact on the weather in Iowa and across much of North America. “La Nina, during the growing season for us, does increase our risk of heat and dryness but right now, we don’t expect that to happen,” Todey says. “My main concern with the growing season right now is how quickly can we get things moving, how quickly can we get soils dried out and things in the ground so we don’t get delays again.”
A warming ocean surface produces an El Nino pattern which can also have strong effects, including wetter weather in the Midwest.