A continued active weather pattern is expected over the next few days as one weather system moves out of the eastern Midwest and Great Lakes region and another one moves into the Plains and upper Midwest. Already by this evening and overnight into Tuesday morning, south to southwest winds are expected to increase especially from Nebraska and western Iowa north into the Dakotas and Minnesota as low pressure deepens along the United States/Canada border in the northern Plains. A Low corn earworm migration risk is in place in this area but the risk is quite minimal as much of this area saw a freeze last week so crops are either past critical stages or are no longer growing.
As the cold front pushes east, the Low risk area shifts east with it for Tuesday night and Wednesday morning to include fields from southeast Iowa into northwest Illinois and southeast Wisconsin into the Great Lakes region and southwest Ontario, Canada. Slightly more favorable conditions may exist especially in Michigan and Ontario for some isolated flights.
Thereafter, no corn earworm migration risk is predicted due to a lack of southerly or strong north or northwesterly flow.