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, May 29, 2007, 9:30AM central time
Short-term (present to 48 hours):
Day 1 (Tuesday 5/29/2007 noon to Wednesday 5/30/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is west of US 63 and south of I-94, including most of the Dakotas, Nebraska, Kansas, southern Minnesota, Iowa, and Missouri. Very low risks exist to the east of this area to I-57 and Lake Michigan.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning shows an area of low pressure over extreme northeast North Dakota, with a cold front southwest of the low through the eastern Dakotas and central Nebraska. Showers and thunderstorms are found along the front mainly in Nebraska and points south. Further south, another area of low pressure is over southeastern Colorado. High pressure is observed over extreme southern Ontario near Windsor, with the persistent high pressure off the Georgia coast in the Atlantic Ocean. South winds are found primarily to the west of the Mississippi River, with southeasterly winds further to the east.
As the day progresses, the low pressure in North Dakota will only move a little bit to the east, possibly into northern Minnesota or southwestern upper Ontario. Meanwhile, the low pressure in Colorado may move northeast along the front, enhancing showers and thunderstorms along the front. The strongest southerly winds will continue to be focused west of the Mississippi River through midday Wednesday, and this is also where the majority of the precipitation and potential insect drop zones will be located. Therefore, a Low risk of insect migration is forecast west of US 63 and south of I-94 for Day 1. A very low risk of insect migration is forecast further east to I-57 and Lake Michigan for more scattered precipitation and southerly winds. No risk is forecast to the east and north across the eastern Midwest and Ontario due to the influence of high pressure and winds from an unfavorable location for possible insect source regions.
Day 2 (Wednesday 5/30/2007 noon to Thursday 5/31/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is south of I-94, east of I-29 north of I-80 and east of US 81 south of I-80, with the risk as far east as I-57, including southern Minnesota, Iowa, eastern Kansas, Missouri, Illinois, and far southern Wisconsin. Very low risks are forecast as far east as I-75 mainly south of I-94.
Click Here For The Day 2 Risk Map (opens a new window)
During the Day 2 forecast period, low pressure moves very little and essentially stalls over the Dakotas. Meanwhile, the cold front is expected to move to the east, potentially reaching the I-55 corridor. Showers and thunderstorms are expected up and down the length of the front, and with southerly winds continuing from source regions in Oklahoma and Arkansas, a Low risk of insect migration is maintained in the forecast but shifted further to the east to I-57 but mainly south of I-94. Very low risks of insect migration are forecast as far east as I-75, again south of I-94 where more direct southerly winds are expected. No risk of insect migration is forecast west of I-29 north of I-80 and west of US 81 south of I-80, and also east of I-75 including eastern Ohio, eastern Kentucky, and Ontario due to southeasterly winds vs southerly or southwesterly winds from insect source regions.
Long-term (Days 3 to Day 5: Thursday through Saturday):
Days 3-5 (Thursday 5/31/2007 noon to Saturday 6/2/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area covers much of the Midwest, mainly east of US 83 to I-75 south of I-94.
Click Here For The Days 3-5 Risk Map (opens a new window)
Low pressure is expected to remain or reorganize in the Plains through the period before potentially lifting out of the area by the end of the weekend. Since low pressure remains over the northern Plains states, southerly winds are expected across much of the Midwest mainly west of I-75, and with a continued chance of showers and thunderstorms, a Very Low risk of insect migration is forecast mainly east of US 83 but west of I-75. Higher risks are not placed in the forecast at this time due to great uncertainty in the strength of southerly flow ahead of the low pressure and cold front, and also coverage of precipitation areas (and subsequent insect drop zones). As the week progresses, we will continue to monitor forecasting trends and if a more focused area of precipitation and/or southerly winds appears likely to occur, the forecast risk of insect migration will be adjusted accordingly.
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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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