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 17, 2007, 11AM Central Time
Short-term (present to 48 hours):
Day 1 (Thursday 5/17/2007 noon to Friday 5/18/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is across the southwestern quarter of Kansas, south of I-70 and west of I-35/I-135.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning shows a large area of high pressure dominating the upper Midwest, centered over northern Iowa. To the east of the high pressure, northerly winds are observed east of the Mississippi River while to the west of the high, southerly winds have begun to return to the Plains states. Low pressure is just beginning to develop over northeastern Montana. Little in the way of precipitation is observed anywhere in the forecasting area outside of a few scattered showers in Ohio and southwestern Ontario.
As the next 24 hours progresses, the high pressure will slowly drift off to the east, only reaching central Illinois by the end of this forecasting period. Northerly winds will continue to the east of the high pressure, so no risk of insect migration is forecast across the eastern Midwest, the Great Lakes, and Ontario province. To the west, southerly winds will likely reach all the way up to the United States and Canada border in the Plains, but little in the way of precipitation close to possible insect source regions is expected. The only exception to this is across far southwestern Kansas where a few showers or storms are possible later tonight into tomorrow morning. Due to the close proximity to potential insect source regions in the Texas and Oklahoma panhandles and the possibility of insect drop zones near/in the precipitation areas, a Very Low risk of insect migration is forecast for far southwestern Kansas.
Day 2 (Friday 5/18/2007 noon to Saturday 5/19/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is along and south of I-70 and west of US 65 including most of Kansas and far western Missouri.
Click Here For The Day 2 Risk Map (opens a new window)
The high pressure currently dominating most of the central United States is expected to continue to drift southeast from Illinois into the middle and lower Mississippi River valley by midday Saturday. The high is rather large, so it will continue to negate any direct flow off the Gulf of Mexico and from known corn earworm source regions in Texas and southwestern Arkansas. However, any insect source regions in western Texas and the Texas and Oklahoma panhandles may provide an insect migration risk on continued southerly winds into especially Kansas and far western Missouri through this period. Southerly winds will likely be found further north into the northern Plains but the short duration, lack of organized precipitation, and less than ideal low-level wind speeds preclude any risk further north than I-70 at least during the Day 2 forecasting period. No risk of insect migration exists anywhere else in the Midwest or Ontario.
Long-term (Days 3 to Day 5: Saturday through Monday):
Days 3-5 (Saturday 5/19/2007 noon to Monday 5/21/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: VERY LOW (2-5%): Greatest risk area is south of I-80 and west of US 65 including Kansas, southern Nebraska, southwest Iowa, and western Missouri. Day 4: VERY LOW (2-5%): Greatest risk area is along and south of I-90 and west of US 65, including Kansas, Nebraska, western Iowa, and western Missouri. Day 5: LOW (5%): Greatest risk area is across Kansas and Missouri, but a VERY LOW (2-5%) risk is also forecast as far north as US 12 and west of I-35 in southern South Dakota, Nebraska, southwestern Minnesota, and western Iowa.
Click Here For The Days 3-5 Risk Map (opens a new window)
The weather pattern in the Days 3-5 forecast period is expected to change little. High pressure will continue to migrate only very slowly across the southern and southeastern United States while low pressure will meander near the Front Range of the Rockies from Montana south to Colorado. A warm front may develop across the far northern Plains and upper Midwest by Day 4, focusing areas of precipitation. To the south of the warm front, southerly winds will continue, originating from source regions in areas west of I-35 and east of I-25 primarily north of US 180 in Texas and New Mexico. As the forecasting period progresses, the associated insect migration risk will spread to the north due to persistent southerly winds, but only Very Low risks are forecast due to less than optimal wind speeds and source regions, plus the lack of more widespread precipitation. A slightly elevated (Low) risk is forecast on Day 5 across Kansas and western Missouri due to at least three solid days of southerly winds having a better chance of moving insects north during this period despite the lack of precipitation.
-----------------------------------------------------------------------------------------------------------
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.
-----------------------------------------------------------------------------------------------------------