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 14, 2007, Noon central time
Short-term (present to 48 hours):
Day 1 (Thursday 6/14/2007 noon to Friday 6/15/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is between US 83 and US 71/I-29, including the eastern Dakotas, Nebraska, and Kansas.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a stationary front from eastern North Dakota southward into South Dakota, Nebraska, and Kansas. Scattered showers and storms are found along the front, mainly in south of I-80 and in eastern North Dakota and northwestern Minnesota. High pressure continues to dominate over the northern Great Lakes states with easterly winds along and south of the high as far west as I-29. Southerly winds are only focused just along and a few miles or kilometers east of the front in the Plains. Further complicating the pattern today is a surface low pressure over Oklahoma, with showers and thunderstorms.
As the day progresses, low pressure moves along the United States and Canada border north of the Plains and drags a weak cold front through areas mainly north of I-90 with precipitation developing along this front. For insect migration purposes, however, this area only poses a Very Low risk due to a continuance of weak southerly flow into this area. The Very Low risk will cover most of the Plains west of I-29 or US 71 to US 83 due to the extremely slow movement of the stationary front and little eastward advancement of precipitation, much like has been observed the past work week. Further east, no risk of insect migration is forecast because the high pressure continues to dominate the weather.
Day 2 (Friday 6/15/2007 noon to Saturday 6/16/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is north of I-80 and west of I-35, including the Dakotas, northern Nebraska, northwestern Iowa, and much of Minnesota.
Click Here For The Day 2 Risk Map (opens a new window)
The low pressure system continues to move to the east through southern Canada, and as it does so, it is expected to drag the cold front along with it, so precipitation chances and possible insect drop out may occur further to the east into Minnesota and northwestern Iowa on Day 2. The very persistent area of high pressure finally begins to slide to the east, bringing more direct southerly flow also further east into the Plains, so the insect migration risk is also shifted further to the east for this reason as well. A continuing no risk of insect migration is forecast to the east as high pressure will still remain in control of the winds and weather over this region.
Long-term (Day 3 to Day 5: Saturday through Tuesday):
Days 3-5 (Saturday 6/16/2007 noon to Tuesday 6/19/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-15%): Greatest risk area on Day 3 is west of I-35 north of I-70, including the Dakotas, Nebraska, northern Kansas, much of Minnesota, western Iowa, and northwestern Missouri. Day 4: Greatest risk is southeast of a line from Rapid City to Grand Forks to International Falls but north of a line from Goodland, Kansas, to Des Moines to Milwaukee to Flint, Michigan. Day 5: Greatest risk area is north of the Ohio River but southeast of I-35.
Click Here For The Days 3-5 Risk Map (opens a new window)
At the very end of the Day 2 period, a new and deeper area of low pressure begins to develop over the northern Rockies or far western Plains in eastern Montana or Wyoming, with a return to southerly flow becoming apparent over the Plains in response to this new system. A warm front is expected to develop east of the low between I-94 and I-90, with precipitation developing especially along and north of the front. As the Day 3-5 period progresses, the low pressure will continue to deepen and move northeast through the upper Midwest and into Canada, and as it does so, it is expected to drag a cold front from northwest to southeast through much of the forecast area. Precipitation is expected to be rather common but likely scattered along the frontal boundary, and with southerly winds continuing ahead of the frontal passage, a Low risk of insect migration is forecast across much of the Midwest through this forecasting period from northwest to southeast. This system does not currently appear as strong as the mammoth low pressure system was that passed through the Midwest a week ago today, so we are not at the present time forecasting a Moderate risk of insect migration but we will continue to monitor conditions as insect source regions have moved to the north in the past week, possibly increasing risks.
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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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