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: Monday, July 9, 2007, 11AM central time
Short-term (present to 48 hours):
Day 1 (Monday 7/9/2007 noon to Tuesday 7/10/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is east of US 81 but west of a line from Detroit to Indianapolis to Paducah, and mainly south of I-90, including far eastern Nebraska, eastern Kansas, Missouri, Iowa, Illinois, southern Wisconsin, southern Michigan, western Indiana, and far western Kentucky.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a cold front draped northeast to southwest from near Sudbury, Ontario to Alpena to north of Milwaukee, Des Moines, Omaha, and north of Goodland, Kansas. Scattered areas of showers and thunderstorms are present along the length of the front with the highest concentration of precipitation in Nebraska and Kansas. To the southeast of the front, winds are from the southwest across the southeastern half of the forecast area. To the northwest of the front, however, winds are currently from the north or northwest. High pressure is located over northern Virginia.
A rather complex weather pattern is expected to be present over the Plains, Midwest, and Ontario during the next 24-48 hours. However, for insect migration purposes and specifically for corn earworm, migration risks appear rather low due to CEW inactivity in major source regions despite a favorable weather pattern for potential insect migration. During the next 24 hours, the cold front will likely sag a little further south from its current position to roughly along I-80 before stalling and dissipating. Showers and thunderstorms will likely continue developing along the front from southern Michigan west into the Midwest and Plains. Southwesterly winds ahead of the front will serve to move any migratory insects north to near the frontal boundary, but any catches in the area are expected to be spotty and low in number. The best risk of insect migration is basically between US 81 and I-69 and I-65 south of I-90 where precipitation thus far has not limited insect activity. Very Low risks surround the Low risk area across much of the remainder of the forecast area to the south of US 2, with risks further east taking into account any scattered or isolated precipitation in southwest winds.
The risk further west is in association with a quickly moving low pressure system expected to track across southern Canada. This low pressure system is expected to drag a cold front rather rapidly to the southeast across the Plains later tonight into tomorrow morning, with southerly winds continuing north of the front. Ordinarily this pattern would warrant at least a Low risk of insect migration given fairly decent southerly winds across the Plains tonight into tomorrow morning, but with precipitation in Nebraska and Kansas expected to continue today, this may limit insect activity overall. Therefore, just a Very Low risk of insect migration is forecast to cover any more isolated drop-out areas especially in the Dakotas.
Day 2 (Tuesday 7/10/2007 noon to Wednesday 7/11/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is east of a line from St Cloud to Sioux City to Goodland Kansas to I-71, all south of I-94, including southeastern Nebraska, Kansas, southeastern Minnesota, Iowa, Missouri, Illinois, southern Wisconsin, southern Michigan, Indiana, western Kentucky, far western Ohio, and the extreme southwestern edge of Ontario near Windsor.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure currently forming in southwestern Canada will likely move rapidly to the east through southern Canada during the Day 2 forecast period, and at the end of the period is expected to be over eastern Ontario. An attendant cold front will likely also move rather quickly to the southeast. At the start of the Day 2 period, the cold front is expected to be near I-29 north of I-90 and then southwest into Nebraska and eastern Colorado. Southerly or southwesterly winds are expected to continue to the east of the front, and a line of showers and thunderstorms will likely push east or re-develop along the frontal boundary by afternoon tomorrow. Despite a favorable weather pattern for insect migration, just a Low risk of insect migration is forecast due to lack of CEW activity in the source regions and quick frontal movement during the day. Very low risks are extended across the far eastern Midwest and into southern Ontario. No risk of insect migration is forecast across the Plains to the west of I-29 as high pressure and northerly winds are expected to build in.
Long-term (Day 3 to Day 5: Wednesday through Saturday):
Days 3-5 (Wednesday 7/11/2007 noon to Saturday 7/14/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: VERY LOW (2-5%): Greatest risk area is along and south of I-44 and I-70 and east of I-69, including southeastern Michigan, southwestern lower Ontario, southeastern Indiana, Ohio, Kentucky, southern Illinois, and southern Missouri. Days 4-5: NO RISK
Click Here For The Days 3-5 Risk Map (opens a new window)
On Day 3, the front will continue to move to the southeast and will likely be out of the forecasting area by the end of the Day 3 forecasting period. Showers and thunderstorms are expected to continue along and to the southeast of the front, and with southwesterly winds present, a Very Low risk of insect migration is forecast mainly in areas southeast of a line from Toronto to Detroit to Indianapolis to St Louis to Joplin, Missouri for Day 3. Further northwest, high pressure and cooler, drier air on northwesterly winds result in a no risk forecast for insect migration to the northwest of the frontal boundary and expected precipitation areas.
On Days 4 and 5, high pressure is expected to dominate much of the forecast area as a deep area of persistent low pressure develops over the James Bay region. This will result in northerly or northwesterly flow for much if not all of the forecast area on Days 4 and 5. Northerly wind flow and high pressure is not conducive to insect migration, so no risk of insect migration is forecast for these two days.
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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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