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 28, 2007, 6AM central time
Short-term (present to 48 hours):
Day 1 (Thursday 6/28/2007 noon to Friday 6/29/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is along and south of US 24, including much of Kansas, Missouri, central and southern Illinois, Kentucky, Indiana, and Ohio.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a cold front roughly along I-80 east of the Mississippi River and then trailing further southwest to along I-70 west of the Mississippi River. Showers and thunderstorms are most common along and ahead of the front especially west of the river with much more isolated activity to the east. Southerly or southwesterly winds are found to the south of the front, while to the north of the front winds are largely from the north or northwest. High pressure is currently located over Manitoba.
During the next 24 hours, the cold front will continue to shift to the southeast, taking its associated precipitation and possible isolated to scattered insect drop zones with it. Southwesterly flow to the south of the front is expected to be rather weak, and with precipitation currently observed in or near the source region, we will only forecast a Very Low risk of insect migration over roughly the southeastern half of the forecast area, mainly along and south of US 24. No risk of insect migration is forecast north of US 24 as high pressure is expected to build in and northerly winds preclude any insect migration into the upper Midwest and Plains.
Day 2 (Friday 6/29/2007 noon to Saturday 6/30/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is along and west of US 81, including the Dakotas, Nebraska, and Kansas.
Click Here For The Day 2 Risk Map (opens a new window)
The cold front will continue to shift to the south, and is expected to be virtually out of the southern reaches of our forecast area by midday Saturday. Southerly or southwesterly wind flow ahead of this front is expected to be even weaker or non-existent, so despite precipitation expected along the front, we do not see the need to forecast any insect migration risk in association with the departing low pressure area due to such weak flow. However, we will forecast a Very Low risk of insect migration west of US 81 in response to a new low pressure system developing over the northern Rockies or far western Plains states. This low, in combination with the high pressure building south out of Canada, will produce opportunities for southerly winds especially across the Plains states. No risk of insect migration is forecast across the upper Midwest and Great Lakes region as high pressure is expected to be in command.
Long-term (Day 3 to Day 5: Saturday through Tuesday):
Days 3-5 (Saturday 6/30/2007 noon to Tuesday 7/3/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: LOW (5-10%): Greatest risk area is along and west of I-35, including the Dakotas, Nebraska, Kansas, much of Minnesota, western Iowa, and far northwestern Missouri. Day 4: LOW (10-15%): Greatest risk area is along and west of I-55 and Lake Michigan, including the Dakotas, Nebraska, Kansas, Minnesota, Iowa, Missouri, western Illinois, and Wisconsin. Day 5: LOW (10-15%): Greatest risk area is along and west of I-69 and I-65, including Dakotas, Nebraska, Kansas, Minnesota, Iowa, Missouri, Illinois, Wisconsin, Michigan, western Indiana, and western Kentucky.
Click Here For The Days 3-5 Risk Map (opens a new window)
The main focus of the long-term forecast period will be the low pressure in the northern Plains and the high pressure over the Great Lakes region and points east. In between the high and the low, southerly winds will blow from source regions primarily in Kansas and western Missouri. Southerly winds will also be found further south but this area will likely experience precipitation through the Day 3-5 period, so for insect migration purposes, the potential source region will likely be centered further north where precipitation is not as likely to occur. Through the Day 3-5 period, the low pressure will continue to develop and slowly move east as the high pressure moves from the Great Lakes into the eastern United States. As this process occurs, southerly winds will expand further east each day, and with the possibility of precipitation especially north of I-90, we will forecast a Low risk each day, with the risk area expanding to the east. There is uncertainty in the positioning of concentrated precipitation areas especially on Days 4 and 5, and beyond, but with good southerly winds across the area, a rather broad region of Low risk is currently forecast. We will continue to monitor conditions over the next 24 hours to see how this pattern evolves and provide an update tomorrow morning.
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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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