Generally Above-Normal Temperatures, Save Michigan

The period started off with anomalous warmth across almost the entire Midwest. The average temperature was 3-6°F above normal for most states in the region (Figure 1). The most notable warmth came out of Illinois, Iowa, Minnesota and Missouri, where average temperatures were 2.1°F, 3.7°F, 2.5°F, and 2.5°F above average for the period, respectively.

Minimum temperatures were also very noteworthy. The average minimum temperature was anywhere from 3-5°F above normal for much of the region (Figure 2). There was no shortage of record high minimum temperatures across the region to start the week. In fact, there were over 300 record high maximum temperatures and over 650 record high minimum temperatures. (Figure 3). In Kansas City, Missouri, the daily minimum temperature did not drop below 82°F for two days straight, from August 23 to August 25. As a result, a record high minimum temperature of 82°F was set for all three aforementioned days.

When it came to average daily maximum temperatures, they were especially higher than normal early in the period across Iowa and Minnesota. The average daily maximum temperature was 4-7°F above normal for both states (Figure 4). In Iowa, from specifically August 22-25, the average maximum temperature along both the I-80 and I-29 corridors was between 95-100°F (Figure 5).

Temperatures cooled in the second half of the week. However, the only noticeable below-normal temperatures for the overall period were in Michigan. Most of the state came in 3-5°F below normal (Figure 1). In Sault Ste. Marie, from August 23-24, the high temperature did not reach 70°F.

Low Rain Totals For Most

It was a very dry period for most of the Midwest. Large swaths of the Upper Midwest saw little to no rain (Figure 6). That being said, a surface low spawned storms that dropped some healthy rain totals in northern Ohio. Parts of Ohio saw over six inches of rain in 24 hours (Figure 7). Port Clinton and Put-in-Bay saw 1-day maximum rain totals of 6.25 and 6.18 inches, respectively, on August 24. The heavy rains caused “Bash on the Bay”, a concert featuring Pitbull and Luke Bryan, to be canceled due to flooding on the island.

Drought Expanded For The Hardest-Hit Areas

Overall, drought coverage only slightly increased during the final week in August (Figure 8). A sizable area of D0 (Abnormally Dry) conditions were removed from Central Illinois. However, the areas with D2 (Severe), D3 (Extreme) and D4 (Exceptional) drought all saw persistent, or even expanding drought. This is the case for southeast Minnesota and northeast Iowa, where D2 was significantly expanded to D3. Agriculture has suffered as a result of the hot and dry weather, especially in Iowa, where reports of diseased soybean and corn plants have been documented.

Severe Storms Batter Metro Cleveland and Detroit

It was an active week with over 300 storm reports (Figure 9). There were 24 tornado reports, 1 large hail report (2.0”+), 200 wind reports and 12 high wind reports (65 kt+). The report of large hail came out of Au Gres, Michigan on August 23, when an observer reported hail of two inch diameter. Most of the tornado reports, and subsequent confirmed tornadoes, were from a surface low that moved through Michigan and northern Ohio. The most significant report was on August 24 where a confirmed EF2 tornado with a total path of 12 miles tore through Ingham County, Michigan, home to the state capital of Lansing, before weakening into an EF1 tornado in Livingston County, Michigan. Unfortunately, there were three injuries and one death. While this was the strongest of all the tornadoes on August 24, it was not the only one, and the record for the most tornadoes in a single day in Michigan in August was broken. While the tornadoes caused significant property damage, there were also reports of straight line wind damage, including from a 90 mph wind gust out of Livingston County.

The same system spawned tornadoes overnight into August 25 through the Greater Cleveland area. This time, two tornadoes reached EF2 strength—one in Warrensville Heights, Ohio, a suburb of Cleveland, and another in Middlefield, Ohio. They reached winds of 120 mph and 115 mph, and while both caused property damage, no injuries or deaths were reported.

Record-Breaking Heat Index Values

Temperatures alone were record-breaking, as previously mentioned. However, it is important to note the high heat index values early in the period, since this is often more indicative of the real-feel outside. Many locations observed heat index values never recorded before. On August 23, many of Iowa’s towns and cities had heat index values over 120°F. Des Moines, Iowa reached a heat index of 115°F for only the sixth time on record. Chicago tied the record for the number of consecutive days at or above 115°F from August 23-24; the previous two-day stretch was in July 1995. Springfield, Illinois also tied the record for consecutive number of days reaching 115°F from August 23-25, with the previous record set during July 1980.