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 22, 2007
Short-term (present to 48 hours):
Day 1 (Tuesday 5/22/2007 noon to Wednesday 5/23/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is between US 81 and I-35, including the eastern Dakotas, eastern Nebraska, eastern Kansas, much of Minnesota, western Iowa, and northwestern Missouri. Very low risks exist to the east of this area to Lake Michigan and I-55.
Click Here For The Day 1 Risk Map (opens a new window)
The low pressure area currently across the Dakotas is expected to begin lifting to the northeast, and is likely to reach far northern Minnesota or extreme southwestern upper Ontario province by the end of this forecasting period. A cold front will trail to the south and southwest of the low pressure area through the upper Midwest and Plains states. High pressure will be located across the far eastern United States, so southerly winds will be found across the entire forecast area except in the far northwestern Dakotas. Scattered areas of showers and thunderstorms will be likely ahead of the cold front, but will be mainly concentrated into clusters, leaving some areas along the front dry while other areas will receive possible heavy rainfall and severe weather. These clusters of showers and storms will produce scattered insect drop zones along the front but not be widespread. The best chances for precipitation exist along the front east to I-35, so a Low risk of insect migration is forecast in this area. Further east, precipitation is expected to be much more isolated or not occur at all, but with good southerly winds for several days, a Very Low risk is warranted as far east as I-55 and Lake Michigan. Further east, despite southerly winds, no risk of insect migration is forecast due to the distance from insect source regions and lower southerly wind speeds. Also, no risk of insect migration is forecast behind the front in the western Dakotas, western Nebraska, and western Kansas.
Day 2 (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 along and east of I-29 north of I-90 and east of US 81 to the south of I-90 and as far east as Lake Michigan and I-57, including Minnesota, Wisconsin, Iowa, much of Illinois, Missouri, and far eastern Kansas and Nebraska. Very low risks exist to the east of this area to I-69 north of I-74, and I-65 to the south of I-74, mainly across western Michigan and western Indiana, south into the western half of Kentucky.
Click Here For The Day 2 Risk Map (opens a new window)
As the Day 2 forecasting period progresses, the low pressure forecast to be located near the Minnesota/Ontario border by Lake Superior at the end of the Day 1 forecasting period will only move a little to the east as it begins to weaken. Due to the slow movement of the low pressure, the cold front will also move only slowly to the east and southeast, reaching near the Mississippi River. Scattered areas of showers and thunderstorms are expected along the front, with southerly winds continuing ahead of the front across the rest of the eastern Midwest and eastern Ontario. Due to a continued slowing trend in the forecast models, the insect migration risk will also be limited to areas further west, with the greatest risk between I-29/US 81 and west of Lake Michigan and I-57. Lower risks are forecast mainly west of I-69 and I-65. Despite the expected weakening in the system, the insect migration risk will remain in the Low category as the source region for southerly winds is expected to move into Arkansas where CEW and possibly other migratory insects are currently reported to be active. No risk of insect migration is forecast across the Plains west of US 81 on Day 2.
Long-term (Days 3 to Day 5: Thursday through Saturday):
Days 3-5 (Thursday 5/24/2007 noon to Saturday 5/26/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: VERY LOW (2-5%): Greatest risk area is along and east of I-55 including much of the eastern Midwest and southeastern Ontario. Day 4: VERY LOW (2-5%): One area is east of I-65 in Michigan, eastern Indiana, Ohio, eastern Kentucky, and southeastern Ontario. A second area is along and south of I-90 and west of I-35 in Nebraska and Kansas. Day 5: LOW (5-8%): Greatest risk area is along and south of I-90 and west of US 65, with lower risks further east along and south of I-72 and east of US 24. The greatest risk area is currently forecast across Kansas, Nebraska, and western Missouri.
Click Here For The Days 3-5 Risk Map (opens a new window)
An active weather pattern is expected to continue across much of the Midwest and Ontario through the period. The low pressure in Ontario will continue to weaken and slide off to the east, taking the cold front slowly with it. The cold front will likely not make it entirely through the eastern Midwest and southeastern Ontario, so an insect migration risk is forecast along and ahead of the frontal passage throughout Days 3-5. The front is expected to stall or even move back to the north by late in Day 4 and into Day 5 and beyond as a new area of low pressure forms in the western Plains states by Day 4. Exactly where this low pressure develops and where the front is located is not easily forecast this many days out, but will likely be between the I-70 and I-90 corridors by Day 5 as high pressure across the upper Midwest near the United States and Canada border will likely act to keep the front further south by the end of the week. Due to good southerly flow from origin points in the Texas and Oklahoma panhandles and nightly (nocturnal) thunderstorm clusters moving along and north of the front during optimal time for insect migration, an upgrade to Low risk of insect migration is placed in the forecast starting on Day 4 to the south of I-90 and west of I-35, then west of US 65 on Day 5. We will continue to monitor this system as the week progresses and provide updates as necessary throughout the week.
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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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