The weather pattern across the central United States is expected to transition back into a more active southwest flow over the next week or so as high pressure re-establishes itself over the southeast United States. The result will be an increase in south to southwest wind days across much of the Plains and corn-growing region which may lead to isolated/scattered corn earworm flights.
Southerly winds are expected to commence across the central Plains later today and continue into tonight but will not expand in coverage or strength to warrant a corn earworm migration risk until Saturday night and Sunday morning. By that time, south to southwest winds originating in Oklahoma, Texas, Arkansas, and northwest Louisiana will blow north and could interact with rainfall near a warm front in Iowa, Illinois, and Missouri. Low corn earworm migration risks are in place across this region.
In the extended period, a low pressure system and attendant cold front are expected to traverse from west to east across the Plains and the corn-growing region. With high pressure in the southeast United States holding firm, south to southwest winds and occasional shower and thunderstorm clusters that may cause insect drop-out results in a broad area of Low migration risk. The risk area is initially focused in the Plains and western Midwest but advances east into the eastern Midwest and Great Lakes region by Monday night and Tuesday of next week.