A potent but somewhat compact low pressure system currently located along the North Dakota/Manitoba/Saskatchewan border will move east into the Great Lakes region by midday tomorrow. A cold front trailing south of the low pressure will serve as the dividing line between southerly winds and westerly/northwesterly winds. A Low corn earworm migration risk is predicted east of the front from eastern Iowa into Wisconsin and east into fields in lower Michigan, Ontario, northern Illinois, Indiana, and Ohio late this evening into early tomorrow morning. Scattered precipitation especially in the Great Lakes region in combination with south to southwest winds may produce some isolated moth flights.
After midday Wednesday, no corn earworm migration risk is predicted due to a lack of stronger/focused southerly or northerly winds. A ridge of high pressure is expected to move into the Plains/Midwest and should keep any wind speeds rather limited through the remainder of the forecast period.