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, July 18, 2007, 8AM central time
Short-term (present to 48 hours):
Day 1 (Wednesday 7/18/2007 noon to Thursday 7/19/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (10-15%): Greatest risk area is east of US 81, south of I-90, north of I-70, and west of I-75, including southeastern South Dakota, eastern Nebraska, northeast Kansas, northern Missouri, Iowa, extreme southern Minnesota, extreme southern Wisconsin, northern and central Illinois, northern Indiana, and Ohio.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a low pressure center over north central Nebraska with a persistent stationary front east of the low across northern Nebraska, northern Iowa, and then southeast into central Illinois, Indiana, and southern Ohio. Several clusters of showers and thunderstorms are lined up along and north of the front from north central Iowa southeast into eastern Indiana and Ohio, with additional showers and storms also over the western Dakotas north of the low pressure area. To the north of the front, winds are from the east or north, while to the south of the boundary, winds continue out of the south.
During the next 24 hours, the low pressure in the Plains is expected to move a little further to the southeast in response to high pressure dropping due south out of Canada. The high pressure will also cause the front to begin to push to the south, albeit slowly, so as we move into the afternoon and overnight hours, additional showers and storms are expected to redevelop over the same areas from northern Iowa southeast into northern Illinois and Indiana, right along and to the north of the front. Southerly or southwesterly winds are expected to continue to feed into this region, and with some CEW specifically active in source regions from southwest Kansas east to northeast Arkansas and southeast Missouri, a high end Low risk of insect migration is warranted, mainly focused along and either side of the I-80 corridor from US 81 east to I-75. Very Low risks surround the Low risk area to account for the possibility of more local scattered insect drop out. No risk of insect migration is forecast across the upper Midwest, Great Lakes region, or northwest Plains as wind flow in these areas is expected to be unfavorable for insect migration.
Day 2 (Thursday 7/19/2007 noon to Friday 7/20/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is along and south of US 24, east of US 83, including southeast Kansas, much of Missouri, central and southern Illinois, Kentucky, much of Indiana and Ohio.
Click Here For The Day 2 Risk Map (opens a new window)
The front will continue to advance to the south, and during the Day 2 period is expected to get a good push to the south due to high pressure dropping south from Canada into northern Minnesota. Showers and thunderstorms will continue to be rather prevalent along the front as it drops south, especially from eastern Kansas east to the Ohio and Pennsylvania state border. The best risk of precipitation is along and south of US 24, and with southerly winds expected to continue along and south of the front, a Low risk of insect migration is forecast. The risk probability is lowered due to decreasing southerly or southwesterly winds from source regions to precipitation areas, and also the stronger winds are expected to be during the day versus during the night. No risk of insect migration is forecast across the upper Midwest and much of the Plains as high pressure and associated calm or northerly winds dominate the weather.
Long-term (Day 3 to Day 5: Friday through Monday):
Days 3-5 (Friday 7/20/2007 noon to Monday 7/23/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk on Day 3 is west of US 81, including much of the Dakotas, Nebraska, and Kansas. On Day 4, the risk shifts east to the US 65 corridor, including the Dakotas, Nebraska, Kansas, western Missouri, western Iowa, and western Minnesota. By Day 5, the risk shifts a bit further east to US 63, including the Dakotas, Nebraska, Kansas, much of Missouri, Iowa, and Minnesota.
Click Here For The Days 3-5 Risk Map (opens a new window)
The front that has been so persistent across the central United States the past several days is expected to push south of the forecast area into the mid-south at the end of the Day 2 period, so no risk of insect migration is associated with this front past Day 2 as high pressure builds into the Great Lakes region.
The focus of insect migration during the long term period will be across the Plains as a new low pressure area develops in Montana and moves only slowly east through the period. Southerly winds are expected to return to the Plains as early as late in the Day 2 period but especially during Day 3 and beyond. Due to lack of precipitation, just a Very Low risk of insect migration is forecast west of US 81 on Day 3, west of US 65 on Day 4, and west of US 63 on Day 5. There is still some uncertainty in how the weather pattern early next week will develop, including how much precipitation is expected to fall and where, and more importantly the strength of winds. For this reason, just a Very Low risk of insect migration is placed in the forecast but we will watch how the system evolves the rest of the week and provide updates as needed.
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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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