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 30, 2007, 9AM central time
Short-term (present to 48 hours):
Day 1 (Wednesday 5/30/2007 noon to Thursday 5/31/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is east of I-29 north of I-80, and US 81 south of I-80 to I-55 and south of I-94, including southern Minnesota, Iowa, Missouri, eastern Kansas, western Illinois, and southwestern Wisconsin. Very low risks exist east to I-65.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning shows an area of low pressure over far northern Minnesota, with a cold front south of the low through western Minnesota, eastern South Dakota, eastern Nebraska, and central Kansas. To the east of the cold front, southerly winds are found across the entire Midwest and Ontario. High pressure is currently located over eastern Pennsylvania. Behind the cold front, northerly or northwesterly winds are observed. Right along the cold front, showers and thunderstorms are rather common in Kansas, central Nebraska, and South Dakota.
During the next 24 hours, the low pressure in Minnesota is expected to move little or possibly even move to the west. The cold front, however, is forecast to move to the east, possibly reaching near the Mississippi River by the end of this forecasting period. Showers and thunderstorms are expected to develop in the warm and somewhat humid air mass ahead of the cold front today, much like has occurred the past several days. The best coverage of showers and storms and southerly winds will be along and a few hundred miles ahead of the cold front, so a Low risk of insect migration will be forecast mainly east of I-29 and US 81 east to I-55 south of I-94 for the Day 1 period. Southerly winds and a few pop-up showers and storms may be found as far east as I-65 today, so a Very Low risk will be extended east to this corridor. No risk of insect migration is forecast across the far eastern Midwest and Ontario due to weaker southerly wind flow and lack of expected precipitation, and also behind the cold front in the western Plains where northerly winds will be predominant.
Day 2 (Thursday 5/31/2007 noon to Friday 6/1/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk is along and east of the Mississippi River mainly south of I-94 to I-75, including southern Wisconsin, Illinois, Indiana, lower Michigan, far western Ohio, and much of Kentucky. Very low risks are forecast further to the east in eastern Kentucky, Ohio, and western lower Ontario.
Click Here For The Day 2 Risk Map (opens a new window)
Low pressure is expected to remain over the Dakotas during the Day 2 forecasting period, with the cold front moving slowly eastward into Illinois and possibly Indiana. Southwesterly winds from source regions in Oklahoma and western Arkansas are expected to occur to the east of the cold front, and with precipitation forecast right along the cold front (potential insect drop zones), a Low risk of insect migration is forecast east of the Mississippi River to I-75 mainly south of I-94. The very low risk area will be shifted to the east into eastern Kentucky, Ohio, and also far southwestern lower Ontario to account for possible precipitation (insect drop zones) and southerly winds reaching into these areas as well. Another area of Very low risks will be forecast west of the cold front from US 81 to the Mississippi River south of I-90 since winds from a southerly component may occur, since the low pressure in the Dakotas will continue counterclockwise flow (southerly winds) to its south and possible scattered drop zones and precipitation in this area. No risk of insect migration is forecast across the Plains and areas north of I-94.
Long-term (Days 3 to Day 5: Friday through Sunday):
Days 3-5 (Friday 6/1/2007 noon to Sunday 6/3/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is east of US 81 south of I-94, as far east as the eastern edge of our forecast region by Day 5.
Click Here For The Days 3-5 Risk Map (opens a new window)
The low pressure that has been very persistent in the Dakotas or upper Midwest the past several days is expected to slowly lift to the east or northeast through the Day 3 to 5 forecasting period, but there is still great uncertainty in how fast, the strength, and also the path of the low during this period and beyond. Southerly winds are expected to continue across much of the Midwest through the period, but are not expected to be overly strong and precipitation will likely be scattered in nature, so given current forecast uncertainty and scattered precipitation coverage, just a Very Low risk of insect migration is forecast from west to east across the forecasting area from Day 3 to Day 5. The best risk does appear to be between US 81 and I-75, mainly south of I-94 throughout the period but to account for forecast uncertainty especially toward the end of the period, the risk will be expanded further east since some forecasting models are showing the system to the east of the Midwest by Day 5. We will continue to monitor conditions and forecasting trends the next few days and provide updates in future forecasts.
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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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