Corn earworm migration opportunities return to the forecast this week especially across the central and southern corn-growing region as a cold front pushes southeast from the northern United States into the central part of the country by late week. Initially, only Low risks are predicted overnight tonight into Tuesday morning across the Plains as any southerly winds will be confined to this area due to high pressure pushing south from the upper Midwest into Missouri by midday tomorrow. Thereafter, south to southwest winds will increase and expand to the east as high pressure drifts southeast into the Tennessee River valley and a cold front pushes into the Plains states. Moderate corn earworm migration risks are predicted from southeast South Dakota and southwest Minnesota southwest through Nebraska, western Iowa, and into Kansas and northwest Missouri. Low risks extend into central Minnesota, southwest Wisconsin, and western Illinois.
By late week and into early next weekend, the cold front is expected to push slowly southeast but may eventually stall out due to strong high pressure in the southeast United States. Persistent south to southwest winds are expected between these two features and the result is a two-night period of Moderate risks from Kansas and Missouri northeast into southeast Nebraska, Iowa, Illinois, and western Indiana. Low risks extend north into Wisconsin, Michigan, and into far western Ohio as well. It does appear the front will push far enough south by next weekend to limit any migration risk by that time.