Discussion: The early autumn pattern will do everything possible to try and drive a cold surge into the Corn Belt next week. Operational forecasts from earlier this week conveyed at least 1 if not 2 days of <32F risk into the Western Corn Belt in early October. However, the updated forecast tells us a lot about cold potential for the Corn Belt as autumn progresses.
First, the freeze risk is cancelled. The ECMWF model was the first to convey this forecast change last Tuesday. Second, ahead of the approaching (modified) chill the Corn Belt is warmer. Des Moines is forecast to spike to 87F Monday. Of course, the warm surge coupled with the upstream approaching cooler air mass will cause excessive rain risk for the Corn Belt…a wetter change in the forecast.
Third, once the cold arrives in Des Moines the 2-meter temperature forecasts indicate a feeble cold risk with upper 30’s likely. No nearby snow cover indicates the 2-meter forecasts are likely correct as <32F and certainly <28F is over the northern/northwestern Great Plains next week near the snow cover produced in Montana.
The Northwest U.S. cold and snow is impressive and in another year would provide the cold air source region to force eastward propagation of cold temperatures into the Corn Belt. But not this year, at least not yet.
The extended-range forecast indicates seasonable temperatures for Des Moines and no freeze risk through October. 12.