Corn earworm migration risks remain in the forecast for the next five days as an active weather pattern is expected to continually result in a south to southwest wind fetch from source regions in the mid-south north into the corn-growing region. The main focus region overnight tonight into early Wednesday morning is centered on the Mississippi River valley as low pressure moves east into northern Missouri or southern Iowa. Precipitation in the Low risk area may inhibit larger scale flights but a more easterly source region across the mid-south compared to the past few nights may result in higher moth counts at flight level. The risk shifts east into the eastern Midwest and southern Great Lakes from Wednesday night into Thursday morning as the low pressure system and attendant cold front shifts east and results in southerly flow to be focused further east.
In the extended period, already by Thursday night southerly winds will be common across the Plains and into portions of the corn-growing region so a Low risk of corn earworm migration is in place mainly south of US 34 and west of US 63, or from southern Nebraska and Iowa into Kansas and Missouri. The risk overspreads much of the corn-growing region along and south of US 20 by Days 4 and 5.