Midwest Overview - June 2009
A Stormy Month
June was a very active month for thunderstorms and severe weather across the Midwest, generally in a wide band extending from Iowa and Missouri east-southeast into Kentucky (Figure 1). Rainfall was heaviest in Missouri and in eastern Kentucky, where more than 10 inches of rain accumulated during the month (Figure 2). Louisville, KY received 9.22 inches of rain, making this the second wettest June on record. June rainfall normal to more than 175 percent of normal across the southern half of the region, but only 50 to 75 percent of normal in eastern Minnesota, northern Wisconsin, and the Michigan Upper Peninsula (Figure 3). Moderate to Severe drought persisted in this region during June, with some expansion of Moderate Drought into western Minnesota by the end of the month according to the June 30 U.S. Drought Monitor.
Monthly rainfall records were set at several locations in Kentucky and Ohio, based on preliminary data. An updated list can found at the National Climatic Data Center web site.
Average daily temperatures during June ranged from 4°F to 5°F below normal in northern Minnesota to 2°F to 3°F across southern Missouri eastward into Kentucky (Figure 4), but this pattern does not tell the whole story. Temperatures during June exhibited wide swings from cool to hot to cool again.
Cool Weather Continues, Then Heat Arrives
The cool weather regime in May continued through the first half of June. Temperatures the first two weeks of the month were below normal across much of the region, ranging from 8°F to 9°F below normal in western Minnesota to near normal along and south of the Ohio River (Figure 5). There was a marked change the last two weeks of the month as an upper level ridge centered over the Gulf Coast states developed northward into the Midwest (Figure 6). High temperatures well into the 90s and dew points in the 70s spread as far north as Minnesota and Wisconsin. While the hot, humid weather made for generally uncomfortable conditions for most people, agricultural producers welcomed these favorable conditions for crop development. Temperatures the last two weeks of the month were near to above normal across the entire region, ranging from near normal in eastern Ohio to 6°F above normal across southern Missouri and Illinois (Figure 7).
There were numerous temperature records set throughout the Midwest this month. During the first two weeks of the month, a few record highs were set across the far southern Midwest, while scores of record low maximum temperatures were set across the northern portions of the region. During the week of June 17-23 more than a hundred record high minimum temperatures were set across the region as the warm humid air settled over the Midwest. Record maximum temperatures were being set in the western portions of Missouri, Iowa, and Minnesota by the end of this week. The heat intensified into the last week of June with numerous records highs set June 24 and June 25.
Back to Unseasonable Cold
An intense upper level low moved over the Great Lakes on June 28 (Figure 8), and the surface cold front that swept through most of the Midwest brought cooler and drier conditions. The slow-moving upper low and the associated extensive area of cloudiness kept high temperatures in the 50s and 60s in the northern Midwest, and in the 70s to low 80s south. Record low maximum temperatures were set across Minnesota, Wisconsin, and Michigan the last two days of the month.
Impacts on Agriculture
The frequent and heavy rain in the central Midwest continued to frustrate agricultural interests. At the end of June soybean planting was still behind schedule in Illinois, Indiana, Kentucky, and Missouri. Soybean planting was nearly complete in Iowa.
The frequent severe weather throughout the Midwest also impacted agriculture. High winds and hail damaged corn and soybeans in some areas. Hail damaged 150,000 acres of crops in Chickasaw and Fayette counties in northeast Iowa on the night of June 17 with about 10 percent of these acres being a total loss. In western Michigan, blueberries and cherries have been taking the worst of the weather. At one farm 100,000 pounds of blueberries were torn from their bushes by winds associated with severe thunderstorms in the third week of June. Some estimates are that the 2009 Michigan blueberry crop will be ten percent smaller than in 2008. Producers will have a better idea of the crop estimate when harvesting begins in July.
For more details on weather and climate events during June 2009, click on the individual weekly report links on the upper right.