Near-to-below-normal Temperatures

Temperatures were near to below normal across the Midwest this week (Figure 1). Statewide average temperatures ranged from 1.5°F below normal in Minnesota to 0.6°F above normal in Ohio. The bigger story this week was the widespread below-normal maximum temperatures (Figure 2). Larger maximum temperature departures were observed near the Great Lakes Region and the Ohio River Valley. Maximum temperatures were 2 to 7°F below normal in Michigan’s Upper Peninsula. Maximum temperatures were also more than 4°F below normal in southeast Missouri and western Kentucky. Minimum temperatures were more than 2°F below normal in northern Minnesota and the Michigan’s UP, but were near to above normal elsewhere (Figure 3). Southern Missouri and Kentucky had areas where temperatures were 1-3°F above normal this week. There were 53 daily low maximum temperature records broken or tied this week, most of which were located in the west (Figure 4).

More than 200 Percent of Normal Precipitation for Several Midwestern Locations

Central Minnesota and west-central Wisconsin picked up more than 2 inches (Figure 5) or 200 percent of normal precipitation this week (Figure 6). Additional locations in the Ohio River Valley received more than 200 percent of normal precipitation. Southwestern Missouri measured 3-6 inches of rain, which was 400 to 750 percent of normal for the week. There were outliers in Missouri where precipitation accumulated to more than 6 inches. Mount Vernon 1.3 NNW, a CoCoRaHS station located in Lawrence County, Missouri, measured 11.77 inches (10.99 inches above normal), which resulted in flash flooding. The associated flooding also caused levee breaks in southeast Missouri. Near-to-below normal precipitation was observed in locations near the Great Lakes this week. Northern Wisconsin and Michigan’s UP measured 25 to 75 percent of normal rainfall and one area in east-central UP measuring 10 to 25 percent of normal rainfall. Northeast Illinois, northern Indiana, southern Michigan, and northwest Ohio saw between 25 and 50 percent of normal precipitation. There were 123 daily precipitation records broken or tied this week (Figure 7).

Storm Reports

There were 237 total storm reports (Figure 8) across the Midwest this week (17-tornado, 104-hail, 25-large hail, 204-wind, 9-high wind). On August 11, a 76-mph wind gust was measured by a weather station in Kannabec County, Minnesota. Most of the associated wind damage was downed trees and powerlines across the region. On August 12, there were several weak tornadoes (EF0 and EF1) in Missouri, Kentucky, Ohio, and Michigan that caused uprooted trees, building damage, and power outages. Three people were injured by a falling tree in Stone County, Missouri on August 14 as a result of storm winds.

Drought Monitor

The August 8 US Drought Monitor had over 45 percent of the Midwest in drought (Figure 9), whereas the August 15 release had just over 40 percent of the Midwest in drought status (Figure 10). Most of the improvement occurred in Illinois, Indiana, and Ohio, as Moderate Drought was removed in spots. Additional improvements were seen in Missouri, Iowa, Wisconsin, and Minnesota.