U.S.: What La Niña Could Mean for the Corn Belt?

El Niño, the weather phenomenon that heats up sea surface temperatures, dissipated in the spring. Meteorologists were waiting for La Niña to take its place, but so far that hasn’t happened, which has come as a surprise. La Niña is characterized by cooler sea surface temperatures and in the Midwest, it can cause ridging patterns, or heat domes.

The past El Niño was one of the strongest since detailed records have been kept in the 1950s, Baranick says, and those “super El Niños” are usually followed by La Niñas the next two following winters.

“I’m actually surprised it’s not going to be as strong as some of the models were forecasting. If you look at the ocean temperatures right now, right along the surface versus it’s cool, but not super cold out there. If you look just below the surface, there’s just a giant pool of cold water, just waiting to come to the surface. All we need is something like the trade winds that go across the equator to really pick up,” he says.

Woznicki says the weather outlook suggests that La Niña could develop, but he doesn’t expect it until at least August or even later into the fall, and there’s no guarantee if it occurs that it will affect the Corn Belt.

“It doesn’t necessarily mean that heat and drought is going to set up over the Corn Belt. It could set up on the East Coast, it could set up in the West Coast, as it has frequently in the more recent La Niña years,” he says.

Woznicki’s outlook calls for the Western Corn Belt to have a better chance to see heat and dryness in the later part of the summer, while the Eastern Corn Belt, which has some dryness now, could be better than areas west of the Mississippi.

If anywhere is susceptible to drier areas, it’s likely to be the northwestern part of the Corn Belt, Montana and the western Dakotas, he says. “Any ridging/drought looks to be more persistent in the Rockies with better showers downstream into the western Corn Belt,” he adds.

Baranick says DTN’s research, which combines historical looks back and computer models, suggest that upper-level high pressure ridges may settle into the Midwest at various times, bringing hot and dry conditions. There are risks for heat domes this summer, but the key is where the ridges go and if they stay in a particular spot or move throughout the season.

“What we’re hoping for is this moving, upper-level ridge throughout the summer,” he says.

In cattle country, the southern Plains and areas north and east of Midland, Texas have had adequate moisture for pasture, while land south and west of Midland are suffering from drier conditions, Woznicki says.

Baranick noted the heavy rain that fell in late June across the northwestern Corn Belt caused extensive flood damage, while an upper-level ridge decreased soil moisture in parts of the Eastern Corn Belt.

“But most areas are sitting in good shape relative to recent years, and especially last year when the entire Corn Belt was facing extensive flash drought conditions. Flash droughts occur when drought occurs quickly, usually due to a lack of rainfall and high heat that saps topsoil moisture,” he says.