An opportunity for corn earworm migration across much of the corn-growing region is possible the next couple days. Low risks are in place tonight and early tomorrow morning from Kansas and Missouri northeast into Minnesota and Wisconsin as well as from Nebraska east through Iowa and into Illinois as a narrow corridor of southerly winds sets up from the central/southern Plains northeast into the corn-growing region. The greatest migration risk in the next week is predicted across the Great Lakes region Tuesday night into Wednesday morning. This area has not seen large numbers of corn earworm moths yet this year and a shorter distance flight especially from source regions in Illinois is possible into southeast Wisconsin, northern Indiana, northern Ohio, Michigan, and also into Ontario, Canada during this time. Lower risks extend further southwest from source regions in the mid-south but much of the crop across the southwest corn-growing region is past critical development stages to see any damage so only Low risks are in place.
Looking ahead to late week and into early next weekend, Low risks are in place across the Plains as an area of southerly winds may inhabit that particular region especially from Thursday night on. With Hurricane Irene likely to track somewhere up the southeast/eastern United States coast by late in the week, it will act as a blocking mechanism for eastward movement of weather systems across the country so any southerly winds will remain further west in the Plains during this time until this tropical system passes.