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 1, 2007, Noon central time
Short-term (present to 48 hours):
Day 1 (Friday 6/1/2007 noon to Saturday 6/2/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is along and east of US 81 to I-57 south of I-94, including southern Minnesota, Iowa, eastern Nebraska, eastern Kansas, Missouri, most of Illinois, and southern Wisconsin. Very low risks are south of I-94 and east to I-75.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map has a low pressure area over South Dakota, with a cold front south of the low through central Nebraska, central Kansas, and south toward Amarillo, Texas. Showers and thunderstorms are rather common ahead of the front at least in a scattered fashion west of I-35 with an organized but decaying cluster of showers and storms in southeastern Iowa. Southerly winds are present in all areas east of the cold front and low pressure.
Throughout the next 24 hours, the low pressure is expected to move just a few hundred miles to the east, possibly reaching southwestern Minnesota by midday Saturday. The cold front will move east, and is expected to be between I-35 and the Mississippi River by the end of the forecast period. Showers and thunderstorms are expected to re-develop across a large area of the Plains, mainly between US 81 and the Mississippi River later today and continue to move to the east overnight and during the morning hours tomorrow. Low level southerly winds from source regions in northeastern Oklahoma and surrounding areas will continue overnight into tomorrow morning, so with good coverage of precipitation and these southerly winds, a Low risk of insect migration is forecast between US 81 and I-57, mainly south of I-94. Further east, more scattered or isolated showers and storms are possible to I-75 and again south of I-94, so a Very Low risk of insect migration is forecast in this area. No risk of insect migration is forecast north of I-94 and across the far western Plains during Day 1.
Day 2 (Saturday 6/2/2007 noon to Sunday 6/3/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is along and east of the Mississippi River and south of I-94. This risk area includes southern Wisconsin, Illinois, southern Michigan, Indiana, Ohio, Kentucky, and southeastern Missouri (where southerly winds and precipitation may last longer).
Click Here For The Day 2 Risk Map (opens a new window)
The persistent area of low pressure is expected to move to near Green Bay, Wisconsin by the end of the Day 2 forecasting period. The cold front is expected to largely wash out or become ill-defined, with a subtle wind shift marking its passage. Showers and thunderstorms will continue to be possible but are expected to become more scattered along and ahead of this wind shift, and southerly winds are also expected to decrease further east. Therefore, only a Very Low risk of insect migration is forecast basically east of the Mississippi River and south of I-94, but also including the southeastern half of Missouri that may stay in southerly flow and precipitation for a longer period of time. No risk of insect migration exists to the west of the Mississippi River as weak westerly or northwesterly flow is expected to lock in for the remainder of the weekend.
Long-term (Days 3 to Day 5: Sunday through Tuesday):
Days 3-5 (Sunday 6/3/2007 noon to Tuesday 6/5/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: VERY LOW (2-5%): Greatest risk area is east of I-69 north of I-74, and east of I-65 south of I-74, including far southeastern Michigan, eastern Indiana, eastern Kentucky, and Ohio. Day 4: NO RISK Day 5: VERY LOW (2-5%): Greatest risk is south of I-80 and west of US 81, including western Kansas and southwestern Nebraska.
Click Here For The Days 3-5 Risk Map (opens a new window)
The low pressure area expected to be over the Great Lakes region by the start of the long term forecasting period is likely to continue to move to the northeast and dissipate with time. Showers and thunderstorms with a weak southerly fetch is expected to continue on Day 3 mainly east of I-69/65, but the risk is very low and only exists on Day 3. By Day 4, some precipitation may be possible across the far eastern Midwest, but feeble wind flow is expected to shift to the west or northwest, so no risk of insect migration is forecast on Day 4 or Day 5 across the eastern Midwest.
By Day 5, however, a new area of low pressure is expected to develop across southern or eastern Colorado, with southerly winds making a return to the far western Plains at the very end of the forecasting period. Some precipitation is also possible at least in a scattered fashion, so with the southerly winds, a Very Low risk of insect migration is put into the forecast across western Kansas and far southwestern Nebraska on Day 5. This early week system bears watching for the rest of the Midwest as it has the potential to be a good insect mover from source regions in the southern United States to Canada mid to late week next week as the southerly wind flow is expected to continue for at least a few days and from known corn earworm source regions in Arkansas and Louisiana. With the introduction of northward migrating potato leafhopper, corn earworm, and leaf rust to portion of the upper Midwest in the past week, additional monitoring of new populations of these and other migratory insects and spores is recommended next week as this system develops.
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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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