Insect Migration Risk Forecast (IMRF)
2007 Growing Season
ACCEC (Analytical Center for Climate and Environmental Change)
Mike Sandstrom and Dave Changnon
Department of Geography
Northern Illinois University
DeKalb, IL 60115
wxtrw44@yahoo.com and dchangnon@niu.edu
Daily Forecast (updated Monday-Friday by Noon Central Time except holidays)
Forecast Release: Friday, June 22, 2007, 11:30AM central time
Short-term (present to 48 hours):
Day 1 (Friday 6/22/2007 noon to Saturday 6/23/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (10-15%): Greatest risk area is east of I-29 and US 71 south of US 20 to northern Illinois, and then southeast of a line from Chicago to Indianapolis to Cincinnati, but north of a line from Omaha to Columbia (Missouri) to Cape Girardeau (Missouri) to Hopkinsville (Kentucky). This area includes Iowa, northeastern half of Missouri, most of Illinois, western and southern Indiana, far southwest Ohio, and western Kentucky.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has an area of low pressure over central Nebraska with a frontal system east of the low through Iowa and then southeast into central Illinois and southern Indiana into central Kentucky. Showers and thunderstorms are scattered along the front from eastern Iowa southeast into Indiana, Ohio, and Kentucky. The main area of low pressure is developing over northeastern Montana into southern Saskatchewan. Southerly winds are found to the south of the Nebraska low and frontal system, with primarily easterly or southeasterly winds to the north of the boundary. South winds are also found across the far western Plains.
During the next 24 hours, the low pressure across Nebraska is expected to move slowly to the east or southeast along the frontal boundary, with redevelopment of showers and storms especially likely to occur somewhere over western or central Iowa this afternoon or this evening. This activity will move to the southeast into northeast Missouri, central and southern Illinois, and southern Indiana through the period, and potentially as far southeast as southwest Ohio and western and central Kentucky. Southerly or southwesterly winds will feed into a rather focused area from source regions in northeast Oklahoma, southwestern Missouri, and southeastern Kansas, so a Low risk of insect migration is forecast east of I-29 and US 71 southeast to I-75, mainly staying to the south of US 20 and I-65 and I-74. Very low risks of insect migration are forecast south of I-90 across the Plains and then further east where more scattered precipitation is expected. No risk of insect migration is forecast across the Great Lakes states and Ontario.
Day 2 (Saturday 6/23/2007 noon to Sunday 6/24/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk areas are 1) east of I-35 and US 71 south of I-80 west of the Mississippi River and then east of the Mississippi River south of I-74, including southern Iowa, Missouri, central and southern Illinois, southern Indiana, southwest Ohio, and western and central Kentucky; and 2) west of US 81, including western North Dakota, western South Dakota, western and central Nebraska, and western and central Kansas.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure currently in Nebraska is expected to slide to the southeast and should dissipate with time, but additional showers and thunderstorms are expected to develop along and ahead of its path, mainly across extreme southern Iowa, Missouri, and southern Illinois and points east. Southerly winds will be rather focused in a small area in Missouri and Illinois, but are strong enough and in close proximity to insect source regions, so a Low risk of insect migration is forecast across areas mainly south of I-80 east of US 71 west of the Mississippi River and then south and west of I-74 and I-75.
A secondary area of low pressure will continue to evolve across the northern Plains, producing stronger southerly flow across the far western Plains to the west of US 81. Precipitation is expected to be most common closer to the low pressure area, but insects can drop out even without widespread precipitation, so with knowledge of active insect source regions currently across the Plains, a Low risk of insect migration is forecast in this area. Further north and east across the northern Great Lakes states and Ontario, winds will be unfavorable for insect migration into these areas and with the expected lack of precipitation, no risk of insect migration is forecast for Day 2.
Long-term (Day 3 to Day 5: Sunday through Wednesday):
Days 3-5 (Sunday 6/24/2007 noon to Wednesday 6/27/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: LOW (10-15%): Greatest risk area is west of I-29 and US 71, including North and South Dakota, Nebraska, and Kansas. Day 4: MODERATE (15-20%): Greatest risk area is in an area bound by US 83 on the west, I-80 on the south, US 2 on the north, and US 169 on the east, including southeastern North Dakota, eastern South Dakota, northeastern Nebraska, northwest Iowa, and southwest Minnesota. Day 5: LOW (10-15%): Greatest risk area is along and southeast of a line from Scottsbluff, Nebraska to Duluth, Minnesota but west of I-65 and I-69, and north of I-94 and Route 401 in Ontario, including Nebraska, Kansas, southern Minnesota, Iowa, Missouri, Wisconsin, Illinois, western Indiana, much of Michigan, and southeastern Ontario.
Click Here For The Days 3-5 Risk Map (opens a new window)
Low pressure is expected to continue to push slowly northeast near the United States and Canada border from the Dakotas into Saskatchewan and Manitoba through the period, with a cold front slowly emerging into the Plains by Days 4 and 5. A warm front is expected to develop east of the low right along the United States and Canada border. Precipitation will be focused along either frontal boundary and near the low pressure area through the Day 3 to 5 period. Southerly winds ahead of the low pressure area and cold front will be rather strong given the connection between high pressure in the eastern United States and the Plains low pressure area. Insect source regions are currently active in Kansas and Nebraska, so with southerly winds expected to increase through Days 3 and 4, a Low risk of insect migration is forecast west of I-29 and US 71 on Day 3, and a MODERATE risk of insect migration on even stronger and more widespread southerly winds and increased precipitation coverage on Day 4 is forecast to the east of US 83 and west of US 169, but south of US 2 and north of I-80. This area may be adjusted or expanded as conditions may change by early next week as we move closer to the Day 4 forecasting period. By Day 5, the low pressure area is further to the northeast into Canada and this will result in somewhat weaker southwesterly winds by Day 5 so the migration risk is lowered into the Low category, and is mainly focused southeast of a line from far western Nebraska into northeast Minnesota but northwest of a line from Toronto to Detroit to Indianapolis to Louisville. We will monitor conditions throughout the weekend and provide updates to the forecast Monday morning.
Insect source regions for this next moderate to strong low pressure area are expected to be primarily from Oklahoma north into Kansas and southern Nebraska versus areas further south and east as has been observed with past weather events that have caused insects to migrate into the upper Midwest. Therefore, attention needs to be focused across the Plains states for insect source regions through the period versus those regions further south and east into southern Missouri and Arkansas for this upcoming weather system.
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Mike Sandstrom and Dave Changnon
Department of Geography
Northern Illinois University
DeKalb, IL 60115
E-mail: wxtrw44@yahoo.com and dchangnon@niu.edu
Temporary IMRF website: http://www.maplecity.com/~sand/cew/imrf.html
DISCLAIMER: The content in this document, and any associated figures, is strictly the opinion of the authors, and should be used for informational purposes only. The authors
assume no liability to those who may use the above content for IPM or other processes.
NOTE: This forecast, while initially developed specifically for migration of corn earworm (CEW), is applicable for all other migratory insects in the Midwest as well, such as the potato leafhopper and armyworm.
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