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: Tuesday, June 26, 2007, Noon central time
Short-term (present to 48 hours):
Day 1 (Tuesday 6/26/2007 noon to Wednesday 6/27/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (10-15%): Greatest risk area is east of I-29 but west of US 51/I-39 north of I-90, including Minnesota and western Wisconsin.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a low pressure area in far southeastern Manitoba with a cold front south of the low into northwestern Minnesota, eastern South Dakota, and central Nebraska. Currently the front is dry, and is only marked by a pronounced wind shift from southerly winds to the east of the front to northwesterly or northerly winds immediately west of the front. High pressure is over North Carolina, and this is producing southerly winds across much of the Midwest, with the strongest winds a few hundred miles east of the cold front. The only precipitation currently in Midwest is a persistent cluster of thunderstorms in southern Illinois with even more isolated activity now developing in northern Illinois.
As the next 24 hours progresses, the low pressure in southern Canada moves rather quickly to the east, and while it does so, the cold front drops further to the southeast. Showers and thunderstorms are expected to develop later today and tonight along the frontal boundary especially north of I-90 in Minnesota and some of this activity may spread east into western Wisconsin. Southerly wind flow into this area has weakened today, and is expected to continue to weaken further during the next 24 hours, so we have dropped the insect migration risk into the Low category for Minnesota and western Wisconsin. Further south, some local or regional migration of insects is possible mainly west of I-35 on light to moderate southwesterly winds ahead of the front, but with the lack of precipitation, a lower end Low risk of insect migration is forecast. Further east into Illinois and also the Great Lakes region, a Very low risk insect migration is forecast for more isolated or scattered precipitation and somewhat less favorable wind speed and direction. No risk of insect migration is forecast across the Dakotas as high pressure from Canada builds into this area.
Day 2 (Wednesday 6/27/2007 noon to Thursday 6/28/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk is southeast of a line from Sault Ste Marie to Green Bay to Omaha to Goodland but north of I-70, including southern Wisconsin, Iowa, southeastern Nebraska, Kansas, Missouri, northern and central Illinois, northern Indiana, northern Ohio, Michigan, and southwestern lower Ontario.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure area moves rapidly to the east and may be into the Atlantic Ocean by the end of this forecasting period. The cold front will continue to move to the southeast, and as the low pressure moves further and further to the east, the cold front will be forced to align itself more west to east with time and slow in forward or southward progress. Showers and thunderstorms are expected to continue in advance and right along the cold front, mainly southeast of a line from Sault Ste Marie to Goodland, Kansas, but remain largely north of I-70, so a Low risk of insect migration is forecast in this area. To the south of I-70, a Very Low risk of insect migration is forecast, mainly to account for any scattered precipitation and local or regional migration events. Further north, high pressure is expected to continue building into the northern Plains and upper Midwest, so no risk of insect migration is forecast during the Day 2 period.
Long-term (Day 3 to Day 5: Thursday through Sunday):
Days 3-5 (Thursday 6/28/2007 noon to Sunday 7/1/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: LOW (5-10%): Greatest risk is along and south of I-70 west of US 71, and then south of US 24 east to I-69, and south of I-69 to the east, including southern Kansas, southern and central Missouri, central and southern Illinois, much of Indiana, Kentucky, far southeastern Michigan, Ohio, and far southwestern lower Ontario near Windsor. Day 4: VERY LOW (2-5%): Greatest risk area is south of I-44 and I-70, including southern Missouri, southern Illinois, southern Indiana, Kentucky, and southern Ohio. Day 5: VERY LOW (2-5%): Greatest risk area returns to the Plains states, mainly west of US 81 including North and South Dakota, western and central Nebraska, and western and central Kansas.
Click Here For The Days 3-5 Risk Map (opens a new window)
On Day 3, the cold front continues to drop to the south, and is expected to bring precipitation and possible insect drop-out zones mainly along and south of a line from Goodland to Kansas City to Chicago to Detroit to Toronto to the southern border of our forecasting region. Precipitation along and south of this frontal boundary is expected to become more widespread but southerly winds are expected to decrease, but we are maintaining a Low risk due to the area being in or in close proximity to active insect source regions. No risk of insect migration is forecast north of this boundary across the northern Plains and upper Midwest as high pressure continues to build into this region.
By Day 4, the cold front continues to move south, and the best chance of insect migration is along and south of I-44 and I-70 in the far southern reaches of our forecasting area. Again, weak southerly flow is expected to mitigate higher insect migration risks over this area, so we are dropping the overall risk level into the Very Low category for more isolated or possibly scattered insect catches.
On Day 5, the frontal boundary is expected to be south of the forecast area in the mid-south region of the United States, but attention shifts back to the northern Rockies and far western Plains where yet another low pressure area is expected to develop in Wyoming or eastern Montana by late in the Day 4 period and continuing into Day 5 and beyond. While precipitation is not likely to occur on much more than an isolated or scattered basis, southerly winds will likely develop across the far western Plains, especially west of US 81. So, if any migratory insects are currently located in the Texas and Oklahoma panhandles or western Kansas, they will have the opportunity to begin moving to the north on increasing southerly winds. For now, a Very Low risk of insect migration is forecast in this area but expect future outlooks later this week and into next week to raise the risk especially across the Plains as this system looks to provide the next good opportunity for insect movement across the Plains states and possibly the Midwest.
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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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