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: Friday, June 15, 2007, Noon central time
Short-term (present to 48 hours):
Day 1 (Friday 6/15/2007 noon to Saturday 6/16/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is north of I-90 west of the Mississippi River and then north of a line from LaCrosse to Green Bay to Alpena, including the Dakotas, Minnesota, northern Wisconsin, and the UP of Michigan.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a low pressure area just north of International Falls, Minnesota with a cold front to the southwest of the low through the Dakotas. A line of showers and a few thunderstorms is found just along and ahead of this frontal boundary across central and eastern North Dakota. An additional area of low pressure is observed over southeastern Oklahoma with more numerous showers and storms near its center. The very persistent area of high pressure that took up residence over the upper Great Lakes most of this week has finally decided to move to the southeast, and is currently centered near Lake Erie. Easterly or southeasterly winds are found over much of the forecast area.
As the next 24 hours progresses, the low pressure is expected to continue moving to the northeast, and will drag its attendant cold front along with it. Showers and thunderstorms are expected to continue to develop along the length of the front, mainly along and north of I-90 west of the Mississippi River but some isolated or scattered activity may make it into northern Wisconsin and the UP of Michigan. Despite the frontal passage and expected precipitation, only a Very Low risk of insect migration is forecast due to virtually no southerly wind flow originating in the insect source regions further south, so any insect drop out will be the result of localized insect movement. No risk of insect migration is forecast across the rest of the forecast area.
Day 2 (Saturday 6/16/2007 noon to Sunday 6/17/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is north of I-90 and west of I-35, including the Dakotas and much of Minnesota.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure that is expected to move through southern Canada today into tomorrow morning is expected to continue to move to the east, reaching Quebec by late tomorrow. The cold front will also move to the east, but as the low outruns the cold front, it will become more west to east across the upper Midwest and northern Plains. A new area of low pressure is likely to begin to develop across northeastern Wyoming and connect to the frontal system. Throughout the Day 2 forecasting period, the cold front will begin to take on warm frontal characteristics and begin to move to the north as the low pressure moves to the northeast into the Dakotas. Southerly winds will return to the Plains states, especially west of I-35, and precipitation is likely to develop especially along and east of the low pressure in the Dakotas and western Minnesota, so with a good southerly wind return to the Plains and acting as a possible insect mover northward, a Low risk of insect migration is forecast for the northern Plains and upper Midwest to the north of I-90 and west of I-35. A very low risk is extended further east along the warm front for more scattered activity and weaker southerly winds into this area. Further east, high pressure will continue to dominate the weather or at least mitigate the risk of insect migration into this area, so no risk of insect migration is forecast across the eastern Midwest and Canada, largely to the east of Lake Michigan and further south to the east of the Mississippi River.
Long-term (Day 3 to Day 5: Sunday through Wednesday):
Days 3-5 (Sunday 6/17/2007 noon to Wednesday 6/20/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (10-15%): Greatest risk area on Day 3 is west of I-35 south of I-90 and west of US 53 in Wisconsin, and mainly to the west of US 71 south of US 136. Day 4: The greatest risk area is east of US 83 to the north of I-90, and as far east as I-55. Day 5: The greatest risk area is mainly south of US 2 between US 83 and I-69/65.
Click Here For The Days 3-5 Risk Map (opens a new window)
The low pressure across the Dakotas is expected to continue to move to the northeast, dragging the cold front further east into the Plains and upper Midwest. Southerly winds are expected to continue across the Plains and western Midwest to the south of the low pressure and warm front. The most focused area of southerly winds and precipitation on Day 3 is expected to be west of I-35 and north of I-90, so a high end low risk of insect migration is forecast across this area on Day 3, with very low risks further to the east. By Day 4, the low pressure will continue to move to the northeast, with the cold front continuing to move to the southeast but is expected to slow in forward motion. Precipitation is expected to continue especially right along the front, again mainly west of the Mississippi River but some activity may bleed further east to along the I-55 corridor and west of Lake Michigan, so the Low risk area will be expanded further east to account for a slightly eastward movement of the low pressure area. By Day 5, much uncertainty exists in the placement of the low pressure system and attendant frontal boundary as a secondary low pressure system may develop on the southwestern end of the frontal boundary, and may act as an inhibitor to further southeastward movement of the front. Given the uncertainty, we will continue to forecast a rather broad area of Low risk but will back off on expanding the risk further to the east given the slower and stronger trend in the low pressure system or systems by midweek next week. We will provide updates in the forecast early next 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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