(Radio Iowa) – State Climatologist, Justin Glisan says June, July and August have been warmer and drier than normal for the last three years. Glisan says the La Nina weather pattern is to blame and it could impact fall as well. “We still see an elevated chance of warmer and drier temperatures for September and then you look at the seasonal meteorological fall time slice — September October November — we’re seeing that signal through those three months,” Glisan says.

He says La Nina is a cold sea surface temperature anomaly in the Pacific that impacts where the storm tracks set up over the United States. It could hang around through winter. “We don’t want to get ahead of ourselves in terms of winter forecasts. But when we do see that La Nina interface hanging around, we do see a tendency towards warmer temperatures across the southern part of the United States, colder temperatures across the northern part of the United States, and then we’re stuck right in the middle of that interface,” he says. “So it’s just a coin flip right now, but again, too far out seasonally.”

Glisan say the La Nina impact has been felt across much of the upper Midwest.