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 31, 2007, 9:15AM central time
Short-term (present to 48 hours):
Day 1 (Thursday 5/31/2007 noon to Friday 6/1/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is east of US 81 to I-35, mainly south of I-94, including much of South Dakota, Nebraska, Kansas, southwestern Minnesota, western Iowa, and northwestern Missouri. Another area of Low risk is east of I-55 to I-75, mainly south of I-94 including eastern Illinois, Indiana, and western Kentucky. Very Low risks are east of I-75 and also between the two Low risk areas along the Mississippi River south of I-94.
Click Here For The Day 1 Risk Map (opens a new window)
A persistent area of low pressure continues to be observed along the North and South Dakota border this morning, with a stationary front east from the low to northern Minnesota, with a cold front from east of Minneapolis south to eastern Iowa, eastern Missouri, and southwest to southwestern Missouri to near Tulsa. Showers are found in a scattered fashion along the front, but with much less coverage and intensity as what was observed further west the past few nights and mornings. Southerly winds continue mainly along and south of the United States and Canada border to the east of the front. Despite the frontal passage, southerly winds continue across much of the Plains since the actual low pressure area is several hundred miles west of the actual front. A few showers and storms are found in the Plains states.
As the next 24 hours progresses, the low pressure in the northern Plains is expected to move little. The cold front near the Mississippi River, however, will move slowly to the east, producing showers and thunderstorms ahead of its path. Southerly winds will be best focused just along and a few hundred miles to the east of the front, with a source region in western Tennessee. A Low risk of insect migration is forecast mainly east of I-55 to I-75 mainly south of I-94. Very Low risks are forecast further east in Ohio and eastern Kentucky, and also far southwestern lower Ontario for more scattered precipitation and weaker southerly flow.
Further west, a good southerly wind flow from source regions in Oklahoma and Texas is expected to develop later today into tonight, with showers and thunderstorms erupting in the Plains states, mainly between US 81 and I-35 south of I-94. Given the strength of low level southerly winds and rather good precipitation coverage, a Low risk of insect migration will also be forecasted across this area given the potential for numerous insect drop zones. In between the two areas of Low risk, right along the Mississippi River, a Very Low risk of insect migration is forecast to cover any scattered showers or storms that may develop in weaker southerly flow. No risk of insect migration is forecast north of I-94 for the next 24 hours.
Day 2 (Friday 6/1/2007 noon to Saturday 6/2/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is between US 81 and I-39/I-55 south of I-94, including eastern South Dakota, eastern Nebraska, eastern Kansas, southern Minnesota, Iowa, Missouri, western Illinois, and southwestern Wisconsin. Very low risks exist to the east of this area mainly south of I-94.
Click Here For The Day 2 Risk Map (opens a new window)
The area of low pressure currently over the Dakotas is expected to drift a little bit to the south or east, reaching the quad-state area of Minnesota, South Dakota, Nebraska, and Iowa by the end of this forecasting period. Southerly winds are expected to continue along and ahead of the low pressure, with a wind shift or moisture boundary expected to develop along and south of the low pressure area along or east of US 81. A good southerly low level flow from Oklahoma is expected to form later in the day Friday and continue into Friday night, with a line of showers and thunderstorms likely to develop in the Missouri River valley later during the day Friday, then move east Friday night into Saturday morning. With good southerly flow mainly south of I-94 and expected precipitation/potential insect drop zones, a Low risk of insect migration is forecast east of US 81 to I-39 and I-55. Further east, a Very Low risk is forecast across the eastern Midwest mainly south of I-94 for scattered precipitation and weak southerly flow in this area. No risk of insect migration is forecast across the western Plains or far upper Midwest.
Long-term (Days 3 to Day 5: Saturday through Monday):
Days 3-5 (Saturday 6/2/2007 noon to Monday 6/4/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: LOW (5-10%): Greatest risk is between I-35 and I-69/65 south of US 10, including eastern Iowa, eastern Missouri, southern Wisconsin, southern Michigan, Illinois, western Indiana, and western Kentucky. Days 4-5: VERY LOW (2-5%): Greatest risk is mainly east of I-57 and south of US 10 both days.
Click Here For The Days 3-5 Risk Map (opens a new window)
Low pressure is expected to continue to move to the east or northeast through the period, and is currently forecast to move from the Plains to northern lower Michigan or near Lake Huron by midday Monday. Southerly winds and precipitation are expected to continue along and ahead of the low pressure area, with the greatest southerly flow and coverage of precipitation likely to occur on Day 3, so a Low risk of insect migration is forecast between I-35 and I-69/65 mainly south of US 10. By Days 4 and 5, the low pressure and associated precipitation shifts to the east, so the eastern forecast area, including lower Ontario, will stand the best risk of insect migration. However, with weakening southerly winds and a possibility for precipitation to become more scattered, just a Very Low risk of insect migration is forecast for both Days 4 and 5 mainly east of I-39 and I-55. There is still some uncertainty in just how fast the low pressure will move, but we will watch forecasting model trends today and tonight, and provide an update in tomorrow’s forecast.
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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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