South to southwest winds originating from northern Texas into Oklahoma will provide a potential source region for corn earworm migration especially in the next 24 hours with lower risks thereafter. High pressure currently in the eastern Midwest should move south into the Tennessee River valley today as low pressure in the Dakotas moves north into Canada. A cold front dropping southeast through the upper Midwest will serve as the focus area for showers and storms as well as the northern edge of the low corn earworm migration risk region. Further south, Moderate corn earworm migration risks are in place from northern Oklahoma, Kansas, central/eastern Nebraska, southwest Iowa, and northwest Missouri where southerly winds have been present for at least the past night or two and where they are expected to be the strongest tonight.
Looking ahead, the cold front will slowly sag south through the corn-growing region this weekend and into early next week before stalling out somewhere between I-80 and I-70. Southerly winds will continue to feed north into the front but on a lighter and more focused scale both Friday night into Saturday morning and then again late in the weekend into early next week. Low risks remain focused from northern Oklahoma northeast into Iowa and Illinois Friday night and Saturday morning, and then in the Plains and western Midwest late in the weekend and early next week.