Corn earworm migration risks continue for the next three nights especially across the Plains and western corn-growing region of the Midwest. Two cold fronts are expected to affect the central part of the country in the next 4-5 days which should not only reduce the high heat and humidity levels but also bring chances of precipitation. This, in turn, may lead to some corn earworm migration possibilities as primarily weak southerly winds persist especially across the Plains into the western Midwest.
Low risks are in place for tonight across Nebraska, Iowa, far western Illinois, and points to the southwest as south to southwest winds blow north and interact with a weakening cold front. Showers and storms are likely to develop over Iowa later this evening and move east, and along and south of the southern edge of this rainfall is where corn earworm drop-out may occur. The risk area focuses back west for Friday night as the next low pressure system develops in the High Plains. By Saturday night into Sunday morning, one of the more favorable weather setups that we have seen for potential corn earworm migration in several weeks sets up across the central part of the country. A cold front should be pushing into the western corn-growing region while high pressure resides over the southeast United States. South to southwest winds are expected to increase between these two weather features. With precipitation expected along the front, a Moderate risk is predicted especially from northeast Kansas into eastern Nebraska, far southeast South Dakota, virtually all of Iowa, far south central Minnesota, far western/northwestern Illinois, and northern Missouri. Low risks surround the Moderate risk area but not quite as far east as predicted yesterday. No risk is seen after Sunday morning into early next week at this time.