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, May 23, 2007, 7AM central time
Short-term (present to 48 hours):
Day 1 (Wednesday 5/23/2007 noon to Thursday 5/24/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is between US 81 and I-55, including the eastern Dakotas, eastern Nebraska, eastern Kansas, Minnesota, Wisconsin, Iowa, western Illinois, and much of Missouri. Very low risks extend east to I-69 north of I-74 and I-65 to the south of I-74.
Click Here For The Day 1 Risk Map (opens a new window)
The surface map this morning has low pressure in eastern North Dakota with a trailing cold front south from the low along I-29 north of I-90, then toward the southwest to near Dodge City in southwestern Kansas. Showers and thunderstorms are scattered along the front but overall are in fairly high coverage, even early this morning when conditions are most stable. High pressure is found across the mid-Atlantic states into the Atlantic Ocean.
The low pressure system is expected to lift to the northeast throughout this forecasting period, reaching extreme southwestern upper Ontario north of International Falls, Minnesota. High pressure is expected to remain across the mid-Atlantic states, so southerly winds will be found across the entire forecast area to the east of the cold front. The cold front is expected to move eastward, reaching the I-35 corridor by the end of the Day 1 forecasting period. Showers and thunderstorms are expected to be rather common along the front, and with continued good southerly flow along and just to the east of the front, a Low risk of insect migration is forecast across the central portion of the forecast area on either side of the I-35 corridor as far west as US 81 and as far east as I-55. A very low risk of insect migration is forecast to the east of I-55 to I-69 north of I-74 and I-65 to the south of I-74. No risk is forecast behind the cold front in the far western Plains and also in the far eastern Midwest and southern lower Ontario where southerly winds will not be as pronounced and a considerably farther distance from southern states source regions.
Day 2 (Thursday 5/24/2007 noon to Friday 5/25/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is between I-35 and I-57, including southeastern Minnesota, Wisconsin, eastern Iowa, Missouri, much of Illinois, and far eastern Kansas. Very low risks exist as far east as I-75.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure system is expected to only move a little eastward in Ontario north of Lake Superior during this forecasting period, so the attendant cold front is also expected to be rather slow-moving through the Midwest. Showers and thunderstorms are expected to continue along the front, and with southerly winds continuing through the period, the Low risk area will be shifted to the east with the front, mainly between I-35 and I-57. The very low risk will also be shifted further east with increasing southerly winds for a longer period of time just a little east of the Day 1 forecast. Across the western Plains, no risk of insect migration is forecast behind the cold front but to the south of I-70, some return southerly flow may occur very late in the forecasting period, so a Very Low risk of insect migration will also be forecast behind the cold front but south of I-70 in western Missouri and Kansas. Due to the extended distance from source regions and a weakening of the low pressure system, no risk of insect migration is forecast across the far eastern Midwest in Ohio and Ontario.
Long-term (Days 3 to Day 5: Friday through Sunday):
Days 3-5 (Friday 5/25/2007 noon to Sunday 5/27/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%) to VERY LOW (2-5%): Greatest risk on Day 3 is south of I-90 and west of I-29/US 71, on Day 4 the greatest risk is south of I-90 but west of I-35, and on Day 5 the greatest risk is south of I-90 and west of the Mississippi River.
Click Here For The Days 3-5 Risk Map (opens a new window)
The cold front will continue to move slowly to the east, but will begin to slow even more or even stop before lifting back to the north especially west of the Mississippi River by Days 4-5 as the new low pressure system begins to develop across the Plains. The risk in association with the cold front across the eastern Midwest on Days 3-4 is lowered to a Very Low risk mainly between I-55 and I-75 south of I-94. Attention then shifts back to the Plains as low pressure and attendant frontal systems develop and move northeast through this forecasting period. Southerly winds will once again likely be observed across the Plains states, especially south of I-90, and precipitation will be possible near the low pressure area and cold front as soon as the Day 3 period. The risk of insect migration will shift northeast with the weather system and attendant precipitation areas/potential insect drop zones. There is still a great deal of uncertainty in this weekend system, so watch for future forecasts to potentially shift the greatest risk areas and the timing as the end of this week approaches.
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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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