As the heat dome that has been affecting the southern United States for the past several months makes a move north into the corn-growing region over the next five days, corn earworm migration risks are expected to remain rather limited and mainly confined to the Plains and western Midwest as southerly winds beneath the heat dome subside. Moderate risks remain in place for later this evening into early Friday morning especially in Nebraska and Kansas as a stronger pressure gradient continues to exist and results in stronger south winds in this area. Low risks extend north into South Dakota and Minnesota and east into Iowa and northwestern Missouri as well.
From late Friday into early next week, the main risk area will be focused across the Plains into the Dakotas, Minnesota, western/central Iowa, and northwest Missouri where mainly diurnally and topographically induced southerly winds shold reside on a nightly basis. Only Low risks are predicted, however, as the overall weather pattern is not conducive to larger scale flights in such a scenario.