Corn earworm migration risks remain rather limited the next five days as high pressure builds into the Midwest and Great Lakes region behind a southeastward advancing cold front. Wind speeds are predicted to remain rather low or even calm throughout much of the corn-growing region the next 2-3 days due to high pressure. As a result, no risk of corn earworm migration is predicted through Friday morning.
By the weekend, high pressure should move slowly southeast into the eastern United States as a new low pressure system develops in southern Canada. Organized return southerly flow is expected to commence by late Friday across the Plains states and a Low corn earworm migration risk is in place south of I-90 and west of US 71 Friday night into Saturday morning. The risk area expands northeast Saturday night into Sunday morning as south to southwest winds move further to the north and east. Low risks extend as far north as South Dakota, Minnesota, and western Wisconsin and east to the Mississippi River by that time.