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, May 25, 2007, 7:30AM central time
Short-term (present to 48 hours):
Day 1 (Friday 5/25/2007 noon to Saturday 5/26/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is west of I-57 and south of I-90, including southern South Dakota, Nebraska, Kansas, southern Minnesota, Iowa, Missouri, and much of Wisconsin and Minnesota. Very low risks extend further east to I-69 and I-65.
Click Here For The Day 1 Risk Map (opens a new window)
The surface map this morning has low pressure over upper Ontario just north of Lake Superior. A cold front is draped south of the low from Michigan southwestward to Saint Louis. Showers and storms are common once again along the front, much like they were yesterday but further east today. A weak area of high pressure is moving into the Plains with the main area of high pressure off the Atlantic coastline. A new area of low pressure is already organizing in eastern Wyoming with southerly winds across the Plains ahead of the low pressure.
An active weather pattern will likely continue through at least midweek next week across much of the Midwest and Ontario. The low pressure currently developing and organizing in the western Plains is expected to move to the east northeast, reaching northeast Minnesota by the end of this forecast period. The low pressure will drag a cold front through the Plains and Midwest, bringing a rather widespread chance of rain to much of the region. With good southerly winds ahead of the cold front from source regions in Oklahoma and western Arkansas and fairly widespread precipitation, a Low risk of insect migration is forecast south of roughly the I-90 corridor and west of I-57, with Very Low risks further north/east to the I-69/I-65 and United States/Canada border near the Great Lakes. No risk of insect migration is forecast in North Dakota, Ontario, or the far eastern Midwest in Ohio and Kentucky.
Day 2 (Saturday 5/26/2007 noon to Sunday 5/27/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is southeast of I-35 to I-65 north of I-70, with Very low risks east of this area and also along/south of I-70 in Kansas.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure area is expected to move from northeast Minnesota into eastern Ontario by the end of this forecasting period, with the cold front located southwest of the low mainly east of the I-35 corridor at the end of Day 1 moving east to a line from roughly Toronto to Indianapolis to Wichita. Precipitation will continue to be rather common in the vicinity of the front, and with continued southerly flow into the area from source regions primarily in Arkansas, a Low risk of insect migration is forecast roughly between I-35 and I-65 with Very low risks further east to the eastern edge of the forecast area where southerly winds are weaker despite a favorable setup. A Very Low risk of insect migration is also forecast south of I-70 in Kansas where the frontal boundary is expected to stall, continuing southerly flow in this area ahead of yet another possible low pressure system developing in the High Plains. No risk of insect migration is forecast across the northern Plains states and in upper Ontario due to northerly or calm winds during the period.
Long-term (Days 3 to Day 5: Sunday through Tuesday):
Days 3-5 (Sunday 5/27/2007 noon to Tuesday 5/29/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is mainly west of I-35 south of I-94 on Days 3-4, and west of the Mississippi River north of I-70 on Day 5. Very low risks extend further north up to the United States/Canada border and also as far east as I-75 but the main focus will once again be across the Plains states west of the Mississippi River through the period.
Click Here For The Days 3-5 Risk Map (opens a new window)
By late in the Day 2 period or during Day 3, another low pressure is expected to develop across the western Plains states. The cold front forecast to move through the Midwest and southern Canada through this weekend is expected to slow with the eastern end of the front largely washing out, while the western end of the front closer to the low pressure redevelops as a warm front and begins to move to the north. There is still uncertainty in the forecast, but enough details appear clear at this time to forecast a northeastward movement of the low pressure system into the upper Midwest, with a warm front to the southeast of the front in the vicinity of the I-90 or I-94 corridor east of I-29, and a cold front southwest of the low into the Plains states. Showers and thunderstorms are expected to be rather common along both fronts, but the best southerly wind flow is expected west of I-35 on Days 3 and 4, and west of the Mississippi River on Day 5. Therefore, Low risks of insect migration are forecast west of I-35 on both Days 3 and 4 mainly south of I-90, with Very Low risks further north to the United States/Canada border and also to I-57/Lake Michigan on Days 3-4 with the risk extending further east to I-75 by Day 5.
Forecasting note: No IMRF will be issued on Monday, May 28th in observance of Memorial Day. Our next forecast will be issued on Tuesday, May 29th, by noon central time.
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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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