A weather pattern change by late this week and into the weekend may result in corn earworm migration risks returning to the corn-growing region. While some southerly winds may be found in the far western Plains as early as tomorrow, a more favorable southerly wind regime that may allow at least isolated moth migration to occur is expected to hold off until Thursday night into Friday. Fields primarily west of a line from Springfield, Missouri to Madison, Wisconsin and also south of US 12 in South Dakota and Minnesota are at risk by that time. The risk shifts east to near Lake Michigan by Friday night into Saturday, and finally covers much of the corn-growing region from the Plains into the southern Great Lakes and eastern Midwest by Saturday night into Sunday. As forecast confidence increases later this week, the possibility does exist for upgrades in the overall migration risk especially by the weekend and into early next week. As a result, please continue to monitor subsequent forecasts for the latest information.