The weather pattern across the corn-growing region is expected to slowly change by late this week and into early next week. A couple of frontal boundaries are predicted to affect the area with the second front late in the weekend or early next week the stronger of the two. As the pattern transitions, the opportunity for corn earworm migration may increase especially during the weekend as a more favorable wind regime combined with a more active source region could lead to a moth flight into the corn-growing region.
For the next three nights, Low corn earworm migration risks remain in place mainly across the southwestern corn-growing region but an extension into the southwest Great Lakes area is also predicted tonight as a weak front slides to the southeast. Isolated to scattered showers and storms may result in some insect drop zones as far northeast as lower Michigan by tomorrow morning. The risk shifts back west for Thursday and Friday nights as a new low pressure center and associated cold front develop in the Plains. By Saturday night into Sunday morning, a Moderate corn earworm migration risk is in place from northeast Kansas and northern Missouri as far north as southeast Minnesota and southwest Wisconsin as stronger southwest winds and a more favorable source region location is expected by that time. Precipitation chances are also expected to increase so more widespread drop zones may be in place.