Normal to Above Normal Temperatures

Temperatures were near normal to above normal across the Midwest this week, with the highest temperature departures in the north (Figure 1). Michigan was warmest and averaged 2.1°F above normal. Minnesota averaged 1.8°F above normal and Wisconsin was 1.5°F above normal for the week. Maximum temperatures followed a similar pattern, but Iowa and northern Missouri also experienced 1-2°F above-normal temperature departures (Figure 2). Minimum temperatures were warmest in the northern Midwest with Michigan observing temperatures more than 4°F above normal (Figure 3). Detroit Willow Run Airport, located in Wayne County, Michigan, had an average maximum temperature of 86°F, average minimum temperature of 62°F, and an average temperature of 74.1°F (2.5°F above normal). The station’s highest maximum temperature of 91°F occurred on August 29, 2022 just prior to a cold front that caused a 5-10°F drop in maximum temperatures on August 31.

Highly Variable Precipitation

The summer of highly variable precipitation continued as heavy rain fell in some areas and others received less than 0.5 inches of rain (Figure 4). The Illinois State Climatologist, Trent Ford, tweeted about the continued highly variable precipitation. Areas receiving heavy precipitation (greater than 2 inches) were southeastern Minnesota, Wisconsin, Michigan, Iowa, Indiana, and northern Kentucky. Based on state average precipitation, Indiana received the most with 119 percent of normal precipitation falling. Wisconsin was right behind, receiving 114 percent of mean precipitaiton this week (Figure 5). Western Wisconsin (Climate Division 4) had the highest precipitation average (2.42 inches) and was 1.59 inches above the 1991-2020 normal. Jackson County, Wisconsin, measured 4.29 inches of rain and 4.02 inches was measured on August 28, 2022 due to the convection along the cold front. On August 30, the National Weather Service Indianapolis office tweeted that Putnam County, Indiana received more than six inches of rain over the last three days. On the other side of the coin, areas in southwestern Minnesota, northwestern Iowa, Missouri, and western Illinois received less than 25 percent of normal precipitaiton. West-central Minnesota, Climate Division 4, received 7 percent of normal precipitaiton for the week. Seven-day average streamflows as of August 30 had above normal streamflows in areas that received the highest precipitation and below normal streamflows in the drier areas. Central-northwestern Indiana and southeastern Iowa had the most stations recording below normal streamflows this week (Figure 6). There were 104 daily precipitation records broken or tied this week, most occurring on an axis stretching from southeastern Minnesota through northeastern Kentucky and western Ohio (Figure 7).

US Drought Monitor

The August 30 Drought Monitor reported some relief to drought and abnormally dry conditions across the Midwest (Figure 8). There was slight improvement to the Severe Drought (D2) and Moderate Drought (D1) in northern and western Wisconsin, southeastern Minnesota, eastern Illinois, and southern Missouri. Expansion of D1 and D2 occurred in southeastern Iowa. Abnormally Dry (D0) conditions in central Michigan, western and southern Indiana, and western Ohio were improved. In total, there was nearly a two percent increase in Midwestern land having no drought status.

Storm Reports

After a slow start, storm intensities picked up mid-late week totaling 375 reports (6-tornado, 22-hail, 347-wind) by the end of the week (Figure 9). There were six tornado reports, five confirmed, on August 27 and 28 in Minnesota. The National Weather Service Twin Cities survey results indicated that all five tornadoes were rated EF-0. There were reports of uprooted trees, downed powerlines, and damage to building structures. There were several reports of winds in excess of 60 mph in Iowa, Minnesota, Illinois, and Wisconsin on August 27 and 28. Storms became a bit more unsettled on August 29 with 172 wind reports in Illinois, Indiana, Kentucky, Michigan, Missouri, and Ohio. These storms were associated with the cold front that brought cooler temperatures to the region by the end of the week. An 81-mph wind gust was reported by a home weather station in Lake County, Indiana, located in northwestern Indiana. Wish TV reported that a northern Indiana drive-in movie theatre screen was damaged and a high school score board was bent over due to the winds. There were also several other 70-mph or greater wind gusts included in the mentioned storm reports. USA Today reported that a 14-year-old Michigan girl died as a result of touching a downed powerline and an additional two teenagers were hospitalized after touching downed powerlines. There were over 3,000 powerlines downed as a result of the storm. In Toledo, Ohio, a woman was tragically killed by a falling tree.