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, May 24, 2007, 6:30AM central time
Short-term (present to 48 hours):
Day 1 (Thursday 5/24/2007 noon to Friday 5/25/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is east of I-35 to I-57, including southeastern Minnesota, Wisconsin, eastern Iowa, much of Illinois, and Missouri. Very low risks extend as far east as I-75.
Click Here For The Day 1 Risk Map (opens a new window)
The surface map this morning shows a potent area of low pressure across far northwest Minnesota with a cold front draped south of the low just west of I-35 from Duluth south to west of Wichita. Showers and thunderstorms are lined up along the entire length of the front mainly south of I-90. High pressure is located off the east coast of the United States, so south or southeasterly winds are found across much of the forecast area to the east of the cold front.
The low pressure is expected to begin moving to the northeast, reaching Quebec by the end of the forecast period. The cold front to the south of the front will continue to move to the east as well, possibly reaching the I-65 corridor by midday Friday. Showers and thunderstorms are expected to be rather common up and down the length of the front, and with good southerly winds continuing ahead of the front from source regions primarily in Arkansas, a Low risk of insect migration is forecast between I-35 and I-57, with lower risks further east where precipitation is possible but is expected to be more scattered and lower southerly wind speeds on average. Also, a Very Low risk of insect migration is forecast across the far southern Midwest in southern Missouri and Kansas as the cold front is expected to become west to east ahead of another developing low pressure over the Plains. Southerly winds will just be commencing during this time, so just a Very Low risk is forecast west of US 65 and mainly south of I-70. No risk of insect migration is forecast across the far northern Plains and in areas east of I-75 and in southeastern Ontario.
Day 2 (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 between US 81 and I-55 mainly south of I-94 including eastern South Dakota, eastern Nebraska, eastern Kansas, Iowa, Missouri, southern Minnesota, Wisconsin, and western Illinois. Very low risks exist across the far western Plains to the west of US 81 and also east of I-55 to I-75, mainly south of I-80 and I-90.
Click Here For The Day 2 Risk Map (opens a new window)
Low pressure at the start of this forecasting period is expected to be near the Colorado/Nebraska/Wyoming vicinity or just to the east, with a cold front draped to the southwest of the low pressure through Kansas and points south. The low pressure system that has been affecting the Midwest and Ontario will be far enough away from the area to not be a great factor to the forecast area besides a residual frontal boundary through the eastern Midwest into southeast Ontario. Some showers and thunderstorms will be possible near this boundary, but for insect migration purposes, the attention will once again shift to the west across the Plains along and ahead of the cold front and new low pressure area. The Plains low pressure area will likely move northeast through this period, possibly reaching Minnesota at the end of the Day 2 period. Thunderstorms are expected to be rather common once again along a trailing cold front to the south of the low pressure area, mainly east of US 81 to I-55 by midday Saturday. Very low risks will be extended to the west and east of this area, mainly south of I-94 across the west and I-80/90 to the east to account for more scattered precipitation and/or weaker southerly wind flow. There is still some uncertainty in the forecasting models and subsequent greatest insect migration risk area, so updates in tomorrow’s forecast may become necessary as this new system rapidly gains strength. No risk of insect migration is forecast across North Dakota and northern Minnesota, and also east of I-75 in Ohio, eastern Kentucky, and Ontario.
Long-term (Days 3 to Day 5: Saturday through Monday):
Days 3-5 (Saturday 5/26/2007 noon to Monday 5/28/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): on Day 3, mainly between I-35 and I-65 south of I-94, including eastern Iowa, much of Missouri, Illinois, extreme southern Wisconsin, and far western Indiana. Very low risks are forecast on Day 4 mainly south of I-80 west of I-75, and then on Day 5 south of I-90 west of the Mississippi River.
Click Here For The Days 3-5 Risk Map (opens a new window)
The Day 3-5 forecasting period is met with much uncertainty due to timing and strength issues of numerous weather systems and how the systems will interact with potential insect source regions to the south and their potential for transportation northward. On Day 3, the low pressure expected to be in Minnesota is forecast to move into the upper Great Lakes on Day 4 and then into southeast Canada by Day 5. The low pressure is expected to drag a cold front from northeast to southwest through the forecast area, producing scattered showers and thunderstorms along the frontal boundary. Low risks of insect migration are forecast between I-35 and I-65 south of I-94 on Day 3 when precipitation is expected to be most widespread along and ahead of the front and southerly winds the greatest in speed. By Days 4 and 5, the precipitation may become more scattered and weaker southerly winds, so just Very Low risks are forecast further east in association with the front. A new potential low pressure system may develop across the western Plains again by late in Day 4 and into Day 5, so a new risk of insect migration on once again renewed southerly winds from source regions in the Texas and Oklahoma panhandles on both Days 4 and 5. Again, there is much uncertainty with the longer range forecast period at this time, but one thing is for certain – the weather pattern across the central United States and Ontario is quite active and this pattern is likely to continue into 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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