July 15-21, 2024

Temperatures

Average temperatures were cooler than normal for almost the entire region this week (Figure 1). An area through central Ohio into central Kentucky, as well as a few scattered areas in Minnesota, Wisconsin, and Michigan averaged near normal. Southeastern Kentucky and Ohio, as well as small areas along Lake Superior in Minnesota and the UP of Michigan averaged 1-2°F above normal. The rest of the region was cooler than normal. The most anomalous average temperatures this week occurred in the western UP and along the Iowa-Missouri border, where averages were 5-6°F below normal.

Average minimum temperatures varied across the region this week (Figure 2). Only a few areas in southern and eastern Kentucky, both peninsulas of Michigan, and the northeast corner of Minnesota averaged above normal this week. All of these areas averaged 1-2°F above normal. Much of Michigan, Ohio, and Kentucky, and portions of Indiana, Wisconsin, and Minnesota averaged near normal. The rest of the region was below normal. West central Iowa and the Wisconsin-Michigan UP border averaged up to 6°F below normal. On July 19th, Decatur, Illinois recorded a minimum temperature of 49°F. This was just the third time in the last 40 years that this station has dipped below 50°F in the month of July.

Average maximum temperatures closely mirrored average temperatures across the region this week (Figure 3). Central Ohio into central Kentucky was near normal. Southeastern Ohio and Kentucky averaged a few degrees above normal, as did a small area in northern Minnesota. The rest of the region was below normal. Parts of central Missouri averaged 7-8°F below normal. In fact, a station at the Vichy, Missouri National Airport only recorded one day this week with maximum temperatures that were not 5°F or more below normal.

Precipitation

Precipitation was rather sporadic across the region this week (Figure 4). Most of Illinois, Indiana, Kentucky, and parts of Missouri, Iowa, Wisconsin, and both peninsulas of Michigan averaged near or above normal for the week. All of Minnesota and Ohio, most of Wisconsin, Iowa, Missouri, as well as central Michigan and northern Kentucky were below normal in rainfall. South central Wisconsin was one of a couple of areas this week that received less than 10 percent of normal rainfall, as they received less than 2 percent. On the other side, southwestern Missouri received up to 500 percent of normal rainfall this week. The average precipitation value for all active stations in the state of Illinois this week was 1.81 inches of rainfall. In other words, the entire state of Illinois averaged 150-300 percent of their normal precipitation for the week.

There were some nice improvements made in regards to drought this week (Figure 5). This week’s drought report takes the rainfall from Post-Tropical Cyclone Beryl into consideration. Because of this, Illinois and Indiana drastically improved their drought conditions, and Missouri and Michigan also improved. Both Indiana and Illinois only have D0 (Abnormally Dry) drought conditions, as all of the D1 (Moderate Drought) conditions have been taken off in those states. On the other end, Ohio and Kentucky saw their drought conditions worsen. D2 (Severe Drought) was introduced in central and eastern Ohio. D1 drought conditions were also introduced in eastern Kentucky. Minnesota, Wisconsin, and Iowa remain drought-free.

Severe Weather

There were 646 storm reports this week (Figure 6). Almost all of the reports came from the derecho of July 15th that affected Iowa, Illinois, and Indiana, and from clusters of storms during the day on the 16th.

Among the most notable reports were 105 mph wind gusts in Camp Grove, Illinois from the evening of July 15th. The same line of storms also produced an EF-2 tornado in the Channahon, Illinois area. 2.5 inch hail was also reported on July 15th in Vail, Iowa.