Weekly Climate Review and Weather Forecast
The heat relented this week, and while temperatures were still above average they were much more pleasant. Average temperatures this week ranged from the mid-60s in northern Illinois to the mid-70s in far southern Illinois, between 2 and 6 degrees above average. September to date temperatures have been right around 1 degree above average for most of the state, but as with most Septembers we have seen quite a bit of variability day to day.
We had a bit of a wetter week across much of the state, breaking a streak of very dry weather that stretched back into August. Rain totals this week ranged from right around half an inch in far northwest Illinois to over 4 inches in parts of the Metro East. While much of southern Illinois has now been near to slightly wetter than normal this month so far, the northern half of the state is still running September to date deficits of around 1 to 2 inches.
As I record this, the remnants of hurricane Helene are pushing through the Carolinas. That system will be pulled to the west by a stronger low pressure system in the Midwest, and will bring interesting weather to the eastern corn belt on Friday and Saturday. Rainfall totals will likely be highest in the lower Ohio valley, including parts of southern Illinois, Indiana, and western Kentucky. Most of southern Illinois is forecasted to pick up another 2-3 inches over the next 3 days, and it’s possible we see a few isolated spots get close to 4 inches. The rainfall gradients will be very large, though, as most of the state north of Interstate 70 will struggle to get more than a half an inch from Helene. Again, we may see bands of heavier rains in central and northeast Illinois depending on how the system tracks west. Unfortunately, the tropical system will also bring strong winds into much of Illinois on Friday and Saturday. Wind gusts between 40 and 60 mph are forecasted from Chicago down to Cairo, so folks should make sure they are taking precaution as they’re out and about on Friday evening and Saturday. Given the quick dry down and some stalk quality issues in corn, we may see some issues with downed corn from the strong winds. Once Helene exits the Midwest, our weather looks to be much milder. Outlooks for the first full week of October are decidedly warmer and drier than normal, as are the longer-term outlooks for mid-October. So, while harvest may be temporarily delayed by tropical weather, at least in southern Illinois, it looks like fieldwork windows will open back up as the calendar turns over to October.