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: Wednesday, June 6, 2007, Noon central time
Short-term (present to 48 hours):
Day 1 (Wednesday 6/6/2007 noon to Thursday 6/7/2007 noon): Relative Risk of Insect migration into the Midwest: MODERATE (15-20%): Greatest risk is between US 183 and Lake Michigan north of I-80, including the eastern Dakotas, northern Nebraska, Minnesota, northern Iowa, Wisconsin, and the western UP of Michigan.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map has a complex area of low pressure emerging from the Rocky Mountains near eastern Wyoming and western South Dakota, with a warm front southeast of the low through Nebraska arcing east to northeast Kansas and Missouri. An area of showers and thunderstorms is observed in northeast Iowa into southeastern Minnesota, with additional more scattered showers north of this area into Minnesota. High pressure is currently located over southern Ohio, so between the high and low pressure areas rather strong southerly winds, especially over the Plains to the south of the warm front are observed, with source regions all the way south into western Texas.
As the next 24 hours progress, the deep low pressure area is expected to move slowly northeast, reaching northwestern Minnesota by midday Thursday. A cold front is expected to also move to the east, and is likely to produce organized severe thunderstorm complexes later today and into tomorrow morning especially north of I-80 between US 183 and I-35 in the eastern Dakotas and Minnesota. With such strong southerly winds and expected high coverage of precipitation, numerous areas of insect drop zones could develop across the northern Plains and upper Midwest, so a Moderate risk of insect migration is forecast. Further south, southerly winds will be very strong but only a Low probability of insect migration is forecast due to more scattered precipitation. Very low risks of insect migration are forecast to I-75 due to increasing southerly winds and the possibility of more widely scattered showers and storms.
Day 2 (Thursday 6/7/2007 noon to Friday 6/8/2007 noon): Relative Risk of Insect migration into the Midwest: MODERATE (15-20%): Greatest risk area is between I-35 and I-71 north of I-70 and south of US 10, including southeast Minnesota, eastern Iowa, northern Missouri, northern and central Illinois, central and southern Wisconsin, lower Michigan, northern Indiana, and northwestern Ohio.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure area is expected to continue to move to the northeast, reaching near James Bay by midday Friday. The cold front will also move east, and is expected to become more active by Thursday evening into the overnight hours. Southerly winds will continue out ahead of the cold front, and will be rather strong with gusts up to 50MPH (80KPH) especially west of I-65. Showers and thunderstorms will rapidly develop along the frontal boundary by Thursday afternoon near or east of I-35 and move quickly to the east, posing not only a significant severe weather risk but also numerous areas of potential insect drop zones, especially between I-35 and I-71 north of I-70. Across the far eastern Midwest, a Low risk of insect migration is forecast due to strong southwesterly winds but more scattered or isolated precipitation during this forecasting period. No risk of insect migration is forecast across the Plains due to a pronounced northwesterly wind shift immediately behind the cold front and falling temperatures.
Long-term (Days 3 to Day 5: Friday through Monday):
Days 3-5 (Friday 6/8/2007 noon to Monday 6/11/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: LOW (5-10%): Greatest risk area is along and southeast of I-44/I-70 from Tulsa to Indianapolis, and then east of I-69 to Detroit, including southeast Michigan, far southwestern Ontario, Ohio, eastern Indiana, Kentucky, southern Illinois, and southern Missouri. Day 4: LOW (5-10%): Greatest risk area is south of I-80 west of I-29/US 71, including southern Nebraska, Kansas, and far western Missouri. Day 5: LOW (5-10%): Greatest risk area is south of I-80 and west of US 63, including southern Nebraska, southern Iowa, Kansas, and much of Missouri.
Click Here For The Days 3-5 Risk Map (opens a new window)
The cold front will continue its eastward march and will likely exit the forecast area by the end of the Day 3 or early in the Day 4 period. However, on Day 3, precipitation and southwesterly winds are expected to continue mainly southeast of a line from Detroit to Indianapolis to St Louis to Tulsa, so a Low risk of insect migration is forecast on Day 3 south and east of these major cities. No risk of insect migration is forecast to the north of the front due to northerly or northwesterly winds and building high pressure across the Plains and Midwest.
By Day 4, the high pressure begins to move to the east, moving into the Great Lakes states. A surface low pressure area is expected to develop along the Front Range of the Rockies once again, and the frontal system that moved south is expected to return north, especially west of the Mississippi River. Southerly winds will once again make a return to the Plains, especially south of I-80 and west of I-29 or US 71, and with some scattered precipitation possible across this region, a Low risk of insect migration is posted for this area. No risk of insect migration is forecast across the rest of the region due to the influence of high pressure or northerly winds continuing.
On Day 5, the low pressure area continues to organize and may begin to lift to the northeast, so the low risk area is expanded further east to near the Mississippi River again south of I-80 where the greatest concentration of both stronger southerly winds and precipitation is likely to occur. However, a Very Low risk of insect migration is also placed in the forecast further north to I-90 and further east to I-57 to account for return of southerly flow further north and east along with the possibility of isolated to scattered precipitation.
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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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