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: Thursday, June 7, 2007, Noon central time
Short-term (present to 48 hours):
Day 1 (Thursday 6/7/2007 noon to Friday 6/8/2007 noon): Relative Risk of Insect migration into the Midwest: MODERATE (15-20%): Greatest risk area is south of I-94 between I-35 and I-29/US 71 east to I-71, including southeast Minnesota, eastern Iowa, Missouri, southern Wisconsin, Illinois, Indiana, southwestern Michigan, western Ohio, and far western Kentucky.
Click Here For The Day 1 Risk Map (opens a new window)
A deep area of low pressure is currently located near the North Dakota and South Dakota border near Minnesota, with a warm front east of the low to Minneapolis and Green Bay. A cold front is located south of the low roughly along the I-29 corridor north of US 36 and then southwest from there along the I-35 corridor. A few showers and thunderstorms have recently developed along this front, and this will serve as the beginnings of an expected rather widespread coverage of severe weather and also insect drop zones across much of the Midwest. The front will continue to move to the east over the next 24 hours, and is expected to reach near I-69 or I-75 by midday Friday. Significant southerly winds will continue to howl ahead of the cold front all the way from the Gulf of Mexico between Florida and Texas into southern Canada. Given the increase in CEW activity (albeit rather low with average counts in the upper teens to around 20 in the Missouri bootheel), a Moderate risk of insect migration is forecast across much of the Midwest between I-35 and I-75 mainly south of I-94. Lower risks of insect migration are forecast further north and east due to the distance that insects would have to travel and the likelihood of insects being able to travel unimpeded further north due to widespread thunderstorms (drop zones) further south. No risk of insect migration is forecast across the western Plains where high pressure is expected to build in on increasing northerly or northwesterly winds.
Day 2 (Friday 6/8/2007 noon to Saturday 6/9/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (10-15%): Greatest risk area is east of I-69 and I-65, including southeast Michigan, eastern Indiana, central and eastern Kentucky, Ohio, and southern Ontario.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure area is expected to move into northeastern Ontario with the cold front continuing to advance to the southeast, and is likely to push out of the forecast area into the Appalachian mountain states by Saturday afternoon. Precipitation is expected along the length of the cold front, mainly across the far eastern Midwest and far southern Ontario. High pressure is expected to expand into the Midwest immediately behind the front, bringing calm or northerly winds to much of the Midwest so no risk of insect migration is forecast across much of the Midwest and northern Plains.
The high pressure, however, is expected to move to the east by the very end of the Day 2 period, bringing a return to southerly winds across the far western Plains, mainly south of I-80 and west of US 81. Scattered or isolated precipitation is possible across especially western Kansas by the end of the Day 2 period, so a Very Low risk of insect migration is forecast in this area.
Long-term (Days 3 to Day 5: Saturday through Tuesday):
Days 3-5 (Saturday 6/9/2007 noon to Tuesday 6/12/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: LOW (5-10%): Greatest risk area is south of I-80 and west of US 65, including southern Nebraska, Kansas, southwestern Iowa, and western Missouri. Day 4: LOW (5-10%): Greatest risk area is south of I-80 and west of US 51, including southern Nebraska, Kansas, southern Iowa, Missouri, and western Illinois. Day 5: LOW (10-15%): Greatest risk area is south of I-90 to I-57, including Nebraska, Kansas, Iowa, extreme southern Minnesota, extreme southern South Dakota, Missouri, and much of Illinois.
Click Here For The Days 3-5 Risk Map (opens a new window)
The cold front that has brought the Midwest rather volatile weather and strong southerly winds will be history by the beginning of this forecast period, so attention once again shifts to the Plains where yet another low pressure area develops in the Front Range of the Rockies in Wyoming or northeast Colorado. High pressure will continue to move off to the east, but will still be in influence of the weather especially across the eastern Midwest and Ontario. Southerly winds are expected to expand further north and east ahead of the low through time, with scattered precipitation expected ahead of the low pressure and developing cold front. On Day 3, the best risk of insect migration will be located across the southwestern forecast area, mainly south of I-80 and west of US 65. By Day 4, as the low pressure continues to develop and high pressure moves east, southerly winds and resultant precipitation are expected to move to the east, so the insect migration risk is also expanded further east to US 51 in Illinois but continuing south of I-80. By Day 5, the low pressure area is expected to deepen further and move to the north, expanding the southerly winds and precipitation further north and east, so the subsequent insect migration risk is shifted further north to I-94 and also as far east as I-57. Through the period, however, the best risk of insect migration will remain across the Plains but with uncertainty in the forecast, the risk areas were expanded further east.
-----------------------------------------------------------------------------------------------------------
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.
-----------------------------------------------------------------------------------------------------------