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, July 10, 2007, 10:30AM central time
Short-term (present to 48 hours):
Day 1 (Tuesday 7/10/2007 noon to Wednesday 7/11/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is east of I-35 and south of US 2, including southeast Minnesota, eastern Iowa, much of Missouri, far southeast Kansas, Illinois, southern Wisconsin, southern Michigan, Indiana, Kentucky, Ohio, and far southwest lower Ontario.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a low pressure center in extreme northwest Minnesota with a cold front along and south of the low pressure across far western Minnesota into southeast South Dakota, central Nebraska, and northeast Colorado. Little in the way of precipitation is currently observed along the frontal boundary. A weak warm front is observed southeast of the low through Minneapolis, Wisconsin, southern Michigan, and southwestern Ontario. To the south of the warm front and east of the cold front, winds are from the south or southwest, while immediately to the west of the cold front, winds quickly shift to the north or northwest. High pressure is currently located over northern Virginia.
During the next 24 hours, the main focus will be with the low pressure system and associated cold front. Southerly winds will continue along and ahead of the cold front, and as the day progresses, showers and thunderstorms are expected to develop in at least a scattered fashion along and ahead of the cold front. The front is expected to be rather progressive, and by midday Wednesday the front is expected to be near the I-75 or I-71 corridor from southwestern lower Ontario south into Kentucky. Given the combination of southerly winds and precipitation in association with the front, a Low risk of insect migration is forecast mainly to the east of I-35 and also primarily south of US 2. Corn earworm trap counts continue to remain rather low in source regions across Missouri and Arkansas, so just a lower end low risk of insect migration is forecast for more isolated or scattered, low count insect migration events. Further northwest, behind or to the west of the cold front, northerly or northwesterly winds will lock in and provide an unfavorable south to north migratory risk so no risk of insect migration is forecast across the northwestern portion of the forecast region in the Plains and extreme upper Midwest.
Day 2 (Wednesday 7/11/2007 noon to Thursday 7/12/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is along and southeast of I-75, including far southeastern Michigan, southwestern lower Ontario, Ohio, and eastern Kentucky. A secondary Very Low risk area is across southwestern Kansas.
Click Here For The Day 2 Risk Map (opens a new window)
The cold front is expected to shift to the southeast and will likely be entirely out of the forecasting region to the east by tomorrow evening. However, before the front moves out of the area, showers and thunderstorms and a period of southwesterly winds justifies a Very Low risk across the far eastern Midwest and Ontario for early in the Day 2 period.
Across southwestern Kansas, an area of low pressure moving through the area is expected to produce an area of showers and thunderstorms at night, and with southerly or southeasterly winds blowing from additional source regions likely not far away in Oklahoma, a Very Low risk for nocturnal insect migration is forecast for this region.
Elsewhere, no risk of insect migration is forecast as high pressure and northerly winds are expected to produce unfavorable conditions for insect movement.
Long-term (Day 3 to Day 5: Thursday through Sunday):
Days 3-5 (Thursday 7/12/2007 noon to Sunday 7/15/2007 noon): Relative Risk of Insect migration into the Midwest: Days 3-4: NONE Day 5: VERY LOW (2-5%): Greatest risk area is south of I-80 and west of I-29 and US 71, including southern Nebraska and Kansas.
Click Here For The Days 3-5 Risk Map (opens a new window)
The main theme for the long-term period will be northwesterly flow to the southwest of a rather deep area of low pressure expected to anchor itself near James Bay north of Ontario, Canada. A few weather disturbances or weak areas of low pressure are expected to slide from northwest to southeast across the Plains and upper Midwest, especially on Thursday and Friday. Showers and thunderstorms will be possible in association with these systems, but with winds from the north or northwest, no insect migration is forecast across the entire forecasting region on both Days 3 and 4.
By Day 5, it is possible that return southerly flow may occur across the southwestern forecasting area to the south of I-80 and also west of I-29 and US 71 as a new area of low pressure develops across the eastern Rocky Mountains. Better chances for migration are possible during next week but this is beyond this current forecasting period. Stay tuned the rest of this week for updates concerning possible migration risks 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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