Midwest Overview - May 2008

Cold and Wet

May was cooler than normal across the entire Midwest, although there was a large gradient in the temperature departures from south to north (Figure 1). Average daily temperatures ranged from about 1ºF below normal in southwestern Missouri to more than 8ºF below normal in northern Minnesota. Most of the region north of the Ohio River experienced temperatures 3ºF to 5ºF below normal. The average temperature since April 1 was 3ºF to 5°F below normal west of the Mississippi River, and from 3°F to near normal east of the Mississippi River. (Figure 2).

Precipitation was generally near to well above normal across the southern two-thirds of the region, and from 50 percent to 75 percent of normal across the northern third (Figure 3). The heaviest precipitation, from 150 percent to 200 percent of normal, occurred in two bands. One extended across the central third of Ohio, and a second extended from southwestern Missouri eastward across southern Illinois into southern Indiana. Notable dry areas were southeastern Kentucky, where precipitation was about 60 percent of normal, and in northwestern Minnesota, where precipitation was less than 50 percent of normal in some locations. The return of drier weather to northwestern Minnesota resulted in the depiction of Moderate Drought (D1) in that area in the May 20 U.S. Drought Monitor. The cool, wet weather slowed progress in spring planting of corn and soybeans in the Midwest during the month. During the first half of the month corn planting was 30 to 50 percent behind the five year average. Several brief periods of dry weather the last half of the month helped producers make progress, and by the end of the month corn planting was 85 to 98 percent complete (Figure 4).

Severe Storms Hammer Region

Severe weather ramped up during the month, and included three strong tornadoes which resulted in multiple fatalities. On May 10 a long-track tornado crossed into southwestern Missouri from Oklahoma. This tornado, on the ground for a distance of 74 miles, was a mile wide at times, causing extensive damage and at least 16 fatalities in Missouri. On May 25 a tornado rated EF5 struck Parkersburg, IA (Butler County) destroying the southern half of the town. The tornado ranged from one-half to three-quarters of a mile wide and was on the ground for more than an hour traveling 43 miles. The storm resulted in seven fatalities and injured more than 70 people. A preliminary estimate by the Federal Emergency Management Agency and the Iowa Homeland Security and Emergency Management Agency attributes $5.8 million in damages to the storm, most in Butler County. The last time an EF5 tornado occurred in Iowa was on June 13, 1976. Also on May 25, a tornado rated an EF3 touched down in Anoka County, MN destroying at least 50 homes and seriously damaging 100 others. The tornado resulted in the death of a 2-year-old child in Hugo, MN and seriously injured eight other people.

For more details on weather and climate events during May 2008, click on the individual weekly report links on the upper right.


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