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: Wednesday, July 11, 2007, 7:30AM central time
Short-term (present to 48 hours):
Day 1 (Wednesday 7/11/2007 noon to Thursday 7/12/2007 noon): Relative Risk of Insect migration into the Midwest: VERY LOW (2-5%): Greatest risk area is along and east of I-71 including eastern Ohio, far southern lower Ontario, and also central and eastern Kentucky. A secondary risk area is located south of US 36 and west of US 71 in Kansas.
Click Here For The Day 1 Risk Map (opens a new window)
The surface weather map this morning has a low pressure area to the south of James Bay in eastern Ontario with a cold front to the south of the low through eastern Ontario to just east of Detroit to Dayton to Paducah. Scattered clusters of showers and thunderstorms are observed along and just ahead of the front. To the west, high pressure is building into the western Dakotas. Northwest winds are observed in most areas to the west of the frontal boundary except in far southwestern Kansas where winds are out of the south ahead of a weak low pressure area in eastern Colorado.
Throughout the next 24 hours, the frontal boundary across the eastern Midwest will continue to move to the east and will likely be east of the forecasting region by this evening. Showers and thunderstorms are expected to continue along and ahead of the frontal boundary, and with southwesterly winds currently ongoing to the east of the front, any insects that are currently up in the sky will have the opportunity to drop out before the front passes through the area. Just a Very Low risk of insect migration is forecast, however, due to low trap counts in the source region. Further to the west, a secondary Very Low risk area is forecast across much of Kansas as a mainly nighttime cluster of showers and thunderstorms is expected to traverse across the state, and with southerly winds across the region, some regional insect migration is possible but again just a Very Low risk given the short duration of southerly winds likely limiting larger insect populations. No risk of insect migration is forecast across the rest of the Plains and upper Midwest as high pressure or northwesterly winds will result in unfavorable insect migration conditions.
Day 2 (Thursday 7/12/2007 noon to Friday 7/13/2007 noon): Relative Risk of Insect migration into the Midwest: NONE
Click Here For The Day 2 Risk Map (opens a new window)
The cold frontal boundary will continue to move to the east during the Day 2 period, well east of the eastern edges of the forecasting region. High pressure is expected to build into the Plains states behind an upper level low pressure system dropping to the southeast across the Great Lakes states on northwesterly winds. These northerly or northwesterly winds are expected to be present over the entire forecasting region, so no insect migration risk is forecast for Day 2.
Long-term (Day 3 to Day 5: Friday through Monday):
Days 3-5 (Friday 7/13/2007 noon to Monday 7/16/2007 noon): Relative Risk of Insect migration into the Midwest: Day 3: NONE Days 4 and 5: VERY LOW (2-5%): Greatest risk area on Day 4 is south of I-80 and west of US 81, including southern Nebraska and western and central Kansas. On Day 5, the risk area shifts to the north and east, reaching to I-90 and also to I-35, including southern South Dakota, Nebraska, Kansas, northwestern Missouri, and western Iowa.
Click Here For The Days 3-5 Risk Map (opens a new window)
As we look ahead to the upcoming weekend and into early next week, the weather pattern is expected to undergo a gradual change from northwesterly flow to one of westerly or southwesterly flow as high pressure moves east across the southern Midwest and the low pressure near James Bay begins to decay and lift to the east. As this occurs, a new low pressure area is expected to develop over eastern Montana or the western Dakotas, and this will bring a return of southerly winds to the Plains states starting on Day 4 and continuing into Day 5 and likely beyond.
No risk of insect migration is forecast on Day 3, however, as northwesterly flow is likely to persist throughout the Plains, Midwest, and Ontario. By Day 4, however, southerly winds are likely to be locked in especially across the far western Plains, with areas closer to source regions south of I-80 and west of US 81 having a Very Low insect migration risk. This risk area expands to the north and east on Day 5, reaching to I-90 and east to I-35 as southerly winds move further to the north and east. Only Very Low risks are forecast due to the lack of precipitation forecasted and not necessarily ideal or strong southerly wind speeds currently in the 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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