July 2021: Strong Storms and Heavy Rain for Parts of the Midwest

The month of July across portions of the Midwest was marked with relatively seasonable temperatures and patterns that brought wet weather, severe storms, and even flooding. Average high temperatures for the month were in the low 80s, which is only slightly below normal. Meanwhile, overnight temperatures averaged in the mid 60s, which was right around or slightly above normal for most of the Midwest. The various weather systems over the month, brought overall rain totals of 4.50-6.50" in Indianapolis, Cincinnati, and Dayton, which is about 1.00-2.00" above normal for July. Amazingly, from the begininning of meteorological summer through mid-July (June 1-July 16), Cincinnati observed 12.61" of rainfall, making it the 2nd wettest summer so far on record! Despite a number of weather systems passing through Chicago, precipitation totaled only around 2.00", which is about 1.00-2.00" below the typical average. This didn't help the ongoing drought across northeastern IL into July, especially for areas towards the WI-IL border.

A number of days during the month also featured a hazy sky due to smoke present within upper-levels of the atmosphere. This smoke originated from wildfires in the western U.S. and southern Canada, transported into the Midwest by the jet stream and other weather patterns. This led to some colorful sunrises and sunsets.

Visible satellite imagery from the morning of July 19th from NOAA/NWS Chicago. Note the milky-white color over the upper Midwest and Ohio Valley, indicating smoke within upper-levels of the atmosphere

 

Smoky weather balloon launch from the National Weather Service in Wilmington, OH.

Chicago Area/Northern IL:

The Chicago area started the month on a dry, sunny, and in the low to mid 70s following a cold frontal passage at the end of June. Conditions remained dry and sunny into the holiday weekend, though it gradually turned warmer and humid with temperatures reaching near 90. Heat and humidity persisted through the 6th before showers and storms returned to the area on the afternoon of the 7th as a cold front passed through. Aside from some locally gusty storms, temperatures also dropped 10 to 15 degrees, with cooler 70s lasting for the next week or so. July 9th through the 18th was marked by several waves of low pressure and scattered showers and storms. However, total rainfall during this time wasn't overally high, with only 0.50-1.50" of rain received around the Chicago Metro area. 

By July 20th, high temperatures climbed back up to near 90 as humidity climbed. A cold front then passed through the region later that day, bringing gusty winds and cooler mid-to-upper 70s the next day. However, temperatures and humidity quickly rebounded for the 22nd and 23rd, with high temperatures in the upper 80s/low 90s and isolated showers and storms. Heat and humidity continued to rise for the 24th with heat index values nearing 100. This set the stage for a broken line of strong to severe storms, which passed through the region in the afternoon and evening with gusty winds. These storms resulted in tree/powerline damage for several spots in Northern IL.

Warm, but dry weather then followed through the 27th with temperatures eclipsing the low 90s. The next "big" event of the month followed for the 28th and 29th as severe weather impacted the region. A few strong storms occurred in the morning and afternoon of the 28th, but the most significant severe weather came overnight from the 28th into the 29th. Wind gusts of 55-75 mph were recorded, leading to areas of tree and structural damage across the region. Breezy conditions and cooler temperatures followed the cold front passage, leading to a mainly dry remainder of the month.

Damage in Northwest Chicago from severe storms overnight 28th into the 29th 

Indianapolis into Ohio:

While Chicago started off the month dry, farther east in Indianapolis and portions of Ohio, it began on the rainier side. Widespread areas of rain on the morning of July 1st, followed by additional areas of scattered showers and storms during the afternoon and evening, some flash flooding in spots. Indianapolis International Airport picked up 2.78" of rain on July 1st alone. Cool and quiet weather followed the next two days under high pressure, with temperatures topping out in the comfortable 75 - 80 degree range. Heading into the 4th, temperatures warmed up to near 90 as humidity also rose, with the heat persisting through the 6th. July 7th through the 13th featured periods of showers and storms at various points as several disturbances passed through the region, though there was some dry time in between. When storms did hit, localized gusty winds and heavier downpours were common.

The 14th into much of the 15th dried out until widespread showers and storms returned late on the 15th. These scattered storms continued through the 16th and 17th, resulting in heavy rain of 1.00-2.00" for most, some flash flooding, and even locally gusty winds at times. Conditions finally dried out for the 18th, with dry and pleasant weather continuing through the 22nd as high pressure dominated.

Up to 1" diameter hail observed near Columbus, OH on July 29th

The 23rd through 25th then featured isolated afternoon and evening showers and storms as high temperatures climbed to 85-90 degrees, with heat indices peaking in the mid-to-upper 90s. The hot weather continued for three more days before additional showers and storms arrived late on the 28th and into the early hours of the 29th. The storms that impacted Ohio during the afternoon of the 29th, however, were more intense with locally damaging winds, hail, and areas of heavy rain. A few tornadoes were also reported, but these occurred south and east of I-71. Conditions gradually turned cooler for the remainder of the month as many dried out.