It sounds like the killing frost that's been on almost every farmer's mind the last few weeks might be on its way in the next week.

Last week, it looked like a warming trend would keep a killing frost at bay into October. But, new models this week show reason for forecasters to point to next Tuesday, September 29, as a day when that frost is likely in many points in the northern half of the Corn Belt.

A cold front will begin making its way into the northwestern Corn Belt -- through the Dakotas and into Minnesota -- on Sunday, and on the back side of that front will trail a cold air mass that will kick temperatures down to the lower 30s in the area that grows around 20% to 25% of the nation's corn and soybeans.

Continue article

ADVERTISEMENT

"Best estimates are that a light frost will hit North Dakota, South Dakota, and northeast Nebraska with the coldest air under minor ridging and radiational conditions causing a freeze in Minnesota and Wisconsin (possibly extreme northern Iowa too) on Tuesday morning," says Allen Motew, ag meteorologist with QT Weather, Inc., in Chicago. "The leading edge the cold air will be crossing Minnesota and South Dakota Sunday. Monday, the lead edge of the cold air will have progressed into Michigan, Indiana, Kentucky, and Missouri.

"Tuesday morning, the greatest risk for frost and some crop damage will be in the eastern Dakotas, Minnesota, western Wisconsin and extreme northern Iowa," he adds.

While the frost will likely end the growing season in the northern tier of the Corn Belt, the crops will probably make it through the dip further south, adds Charlie Notis of Freese-Notis Weather, Inc., in Des Moines, Iowa. Those crops that make it through the chilly conditions early in the week will be rewarded by warmer temps later on, Notis adds.

"The coldest mornings will probably be next Tuesday and Wednesday, with Tuesday probably being the colder of the two. Right now, I think that most places in the Midwest and northern Plains will have lows no worse than the 30s during that time frame, and thus feel that the vast majority of the area will indeed see the growing season continue through that cold," Notis says. "As always though, you will see a few of the normally 'cold' locations dip to 32 or even as low as the upper 20s.

"We should temperatures really warm up again for at least a couple days after that cold air passes," he adds.