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: Tuesday, June 5, 2007, Noon central time
Short-term (present to 48 hours):
Day 1 (Tuesday 6/5/2007 noon to Wednesday 6/6/2007 noon): Relative Risk of Insect migration into the Midwest: LOW (5-10%): Greatest risk area is south of I-80 west of US 65, including southern Nebraska, Kansas, southwest Iowa, and western Missouri.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning shows an area of low pressure along the Ontario/Quebec border with a weak cold front to its south, reaching along the Ohio/Pennsylvania border and then continuing in a much more diffuse pattern along I-64 to southern Illinois. A few showers are found along the front but northerly or westerly flow predominates much of the forecast area all the way west to where a high pressure is located over North Dakota.
As the next 24 hours progresses, the Midwest is expected to see a rather pronounced change in the weather, from tranquil conditions across the Plains to strong southerly winds ahead of a rapidly developing low pressure over eastern Wyoming. The high pressure is expected to move to the east rather quickly, further aiding in the development of southerly winds mainly west of the Mississippi River. In response to the developing southerly winds, a few areas of precipitation are possible the next 24 hours, most notably in Kansas and also further north between I-90 and I-94. For insect migration purposes, however, the best risk will be across the southwestern Midwest and Plains in Kansas and western Missouri closer to active insect source regions, so a Low risk of insect migration is forecast south of I-80 and west of US 65, with Very Low risks as far north as I-94 and as far east as the Mississippi River. Due to the continuation of northwesterly flow over the eastern Midwest and Ontario, no risk of insect migration is forecast to the east of the Mississippi River.
Day 2 (Wednesday 6/6/2007 noon to Thursday 6/7/2007 noon): Relative Risk of Insect migration into the Midwest: MODERATE (15-20%): Greatest risk area is north of I-90 between US 81 and I-39, including the far eastern Dakotas, Minnesota, and western Wisconsin.
Click Here For The Day 2 Risk Map (opens a new window)
Low pressure will continue to deepen and move to the northeast, reaching northern Minnesota by midday Thursday. A cold front will also move to the east, and is expected to be near the US 81 corridor by noon Thursday. Southerly winds will be very strong for this time of year, with some areas experiencing gusts up to 50MPH (80KPH) across the Plains, mainly west of I-35 outside of thunderstorms. The most concentrated areas of precipitation is expected to be in the vicinity of the low pressure, mainly north of I-80 and west of the Mississippi River. A moderate risk of insect migration is forecast where southerly winds are expected to encounter the heavier precipitation north of I-90 between US 81 and I-39 and south of US 2, but lower risks are forecast further south to I-80 and as far east as Lake Michigan. Further east, high pressure will have departed the eastern Midwest and Ontario with southerly winds commencing, but not for a long enough time to forecast any risk of insect migration at this time.
Long-term (Days 3 to Day 5: Thursday through Sunday):
Days 3-5 (Thursday 6/7/2007 noon to Sunday 6/10/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: MODERATE (15-20%): Greatest risk area is between I-35 and I-75 between I-94 and US 36, including southeast Minnesota, northern Missouri, eastern Iowa, southern Wisconsin, northern and central Illinois, northern Indiana, northwest Ohio, and extreme southern Michigan. Day 4: LOW (5-10%): Greatest risk area is east of I-69 and I-65, including southeast Michigan, eastern Indiana, Ohio, and eastern Kentucky. Day 5: LOW (5-10%): Greatest risk area is south of I-80 and west of I-55, including southern Nebraska, Kansas, southern Iowa, Missouri, and western Illinois.
Click Here For The Days 3-5 Risk Map (opens a new window)
On Day 3, the strong low pressure area is expected to move northeast into northeastern upper Ontario south of James Bay. The cold front is expected to move to the I-69 and I-65 corridor by midday Friday. Southerly winds are expected to decrease somewhat as the low pressure area moves to the northeast, but more widespread southwesterly development of precipitation along the cold front is likely, so a Moderate risk of insect migration is forecast from I-35 east to I-75 between US 36 and I-94. Low risks extend all the way to the east edge of our forecasting area including lower Ontario and southeastern Ohio and Kentucky. No risk of insect migration is forecast for the northwestern Plains as they are expected to be under the influence of high pressure or northwesterly wind flow.
By Day 4, the frontal system continues to move to the southeast, with a continuing but lowered insect migration risk where the most widespread precipitation is expected to the east of I-69 and I-65. Further west, the frontal system may become stationary or even move slightly back to the north in response to a developing low pressure area in eastern Colorado. Southerly winds will continue to the south of this boundary so even though precipitation is not expected to be widespread in this area, a Very Low risk of insect migration is maintained due to the area’s close proximity to insect source regions. No risk of insect migration is forecast over the upper Midwest and western Great Lakes.
On Day 5, much uncertainty is in the forecast due to the active weather pattern across the central United States and the daily inconsistencies in the long range forecasting models, so we will be briefer for the Day 5 period. It does appear that the low pressure area in Colorado may move to the northeast by midday Sunday, but where exactly it moves and how strong the associated warm frontal boundary is, and the resultant precipitation, we will only forecast a Low risk over areas south of I-80 and west of I-55 for now, but please continue to stay tuned to later forecasts this week as the system does appear in today’s forecasts to be stronger than it was in the past couple days.
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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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