Midwest Overview - August 2008

---

A Very Dry August

August was an about-face from June and July as far as rainfall is concerned. Precipitation was below normal across the entire region, with only a few isolated areas receiving near normal rainfall (Figure 1). In those areas much of the rain was not spread out across the month, but came during one or two events. Rainfall in August was less than 25 percent of normal from northern Minnesota through northern Wisconsin into northwestern Ohio, as well as the Ohio Valley. The only area to receive normal to above normal rainfall was extreme southern Missouri and parts of central Missouri. For most of the region, August rainfall was well below two inches (Figure 2)

By the end of the month the U.S. Drought Monitor was depicting areas of Moderate Drought (D1) in Minnesota, Wisconsin, and southeastern Kentucky (Figure 3). Abnormal Dryness (D0) expanded across Ohio, Michigan, and Wisconsin. Farmers were reporting large cracks in the ground in some areas, only weeks after torrential rain in June and July. Although some corn is showing some signs of drought stress, impacts of the dry weather on the corn is expected to be minimal since peak development occurs in July. Soybeans are more vulnerable in August as this is the peak development time and dry weather can have a more substantial impact.

 

Not Much Heat or Humidity

Temperatures across the Midwest were generally below normal during the month, with the coolest area in north-central Missouri where departures were 3°F below normal (Figure 4). The central Midwest also had average daily maximum temperatures that ranged from 3°F to 5°F below normal (Figure 5).The warmest area was a band across the northern and eastern portions of the region, where temperatures were near normal to 1.5°F above normal. Repeated intrusions of cooler, drier air kept normally muggy August weather at bay and only a few humid periods occurred during the month.

 

Severe Weather Limited

The most active week of August was the first when a complex of severe thunderstorms raced through northern Illinois and Indiana on August 4 causing widespread wind damage and rain in excess of 4 inches. After this event, most severe weather was scattered or isolated and not of much consequence. The only other significant outbreak was on August 28 when severe thunderstorms rolled through northern and central Missouri and into western Illinois, producing wind damage and locally heavy rain. There were no tornadoes reported in the nine-state Midwest region the last half of the month.

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

-SDH-