July 2020 in the Midwest: Oppressive Heat and Rounds of Severe Weather

The month of July did not disappoint in the temperature department across the Midwest where almost half of the month recorded temperatures at or above 90 degrees! These multiple heat waves allowed temperatures to come in well above average (3 – 5 degrees above normal). The prolonged heat led to numerous rounds of severe storms, but rainfall rates were not all that impressive which led to a decrease in overall precipitation totals. Most places saw a deficit of 0.50 – 1.00”, but areas around Cincinnati received over 3” more than normal due to repeated downpours from thunderstorms. This deficit in rainfall led areas in Indiana and especially Ohio to become abnormally dry to a even entering moderate drought. 

July started off with oppressively hot and dry conditions with temperatures rising well into the 90s each day. These temperatures combined with high humidity led to the heat index to peak to almost 105 degrees each afternoon. This heat and humidity were finally accompanied by a frontal boundary on the 6th mainly between Indianapolis, Cincinnati and Dayton. This helped trigger afternoon severe thunderstorms, which caused several downed trees due to 55 – 65 mph wind gusts. A few of these trees fell on a barn destroying them completely. In addition to the damaging wind gusts, repeated heavy downpours led to a quick 1.00” of rain that briefly caused minor roadway flooding. 

After this initial round of severe weather, the heat and humidity continued throughout the Midwest with temperatures remaining well into the upper 80s to mid 90s. This heat and humidity accompanied by multiple disturbances led to several rounds of severe weather across the entire Midwest from July 7th to the 12th. The main impact was wind gusts of 55 – 65 mph, along with a few instances of dime to quarter sized hail. This caused several downed trees and power lines which produced scattered outages. 

In the wake of this hot, humid and stormy pattern, temperatures cooled some between the 13th – 17th with afternoon highs rising mainly in the 80s with overnight lows dropping into the middle 60s. In addition to the cool temperatures, it was mainly precipitation free except for a few instances of showers on the 15th. This dry stretch helped amplify the already abnormally dry conditions in Indiana and Ohio.  

The cool stretch was extremely short lived before the heat and humidity returned between 18th – 22nd particularly in Dayton, Cincinnati and Columbus where afternoon highs skyrocketed back into the 90s. That said, areas east like Indianapolis and Chicago, were noticeably cooler with temperatures in the 80s. During this stretch, a low pressure system swept across the Midwest from Chicago to Columbus, producing widespread wind damage in its wake due to wind gusts of 55-65 mph. In addition to the severe weather, these storms produced heavy downpours which caused Cincinnati/Northern Kentucky International Airport to receive two inches of rain! This again caused areas of poor drainage and roadway flooding across the region.

After this stretch of hot weather, temperatures fell back into the 80s for most areas between the 23nd – 25th which in terms of July, is still 2-4 degrees above normal. After this cool and dry stretch, the hot weather returned for the 26th – 29th as temperatures rose back into the 90s. Like previous stretches of heat, it led to another round of severe weather in Indianapolis, Cincinnati and Columbus. This round of severe weather generated numerous reports of downed trees and power lines. After a hot and humid month, July ended on a cool note with temperatures in the upper 70s to lower 80s with rounds of showers and non-severe storms. Despite the many rounds of severe weather, areas east of Chicago developed abnormally dry to moderate drought conditions.