June Midwest Summary: Flooding Rains and Intense Heat
Throughout the month of June, Chicago and Rockford saw multiple rounds of flash-flood-inducing heavy rain while numerous stationary fronts sparked sporadic shower and storm activity in the Ohio River Valley. However, regardless of where you were in the Midwest during June, several potent heat waves brought temperatures into the 90s. Summer-time work became difficult when associated heat indices rose over 100 degrees at times throughout the month.
In Chicago and Rockford, two bouts of intense heat caused daily highs to climb into the low to mid-90s. As high pressure built in, the first heat wave occurred mid-month from the 16th-18th marking the hottest Fathers Day (the 17th) since 1995 when spots in Chicago reached 95 degrees. At the end of the month, another hot and humid airmass settled in allowing heat indices on the 29th-30th to soar between 105-115 degrees. Despite these potent heat waves, temperatures ended the month only slightly above average.
Ending well above average in terms of precipitation, Chicago and Rockford saw multiple widespread, heavy rain events during the month. The first came on June 9-10th when 2-3” of rain fell in Chicago and as much as 4-5” in Rockford. A narrow line of storms on the 15th dropped another 2-4” of rain and as flash flooding ensued in the Rockford area, just miles to the east, the bulk of Chicago stayed largely dry. Rockford and into northern spots of Chicago couldn’t catch a break when more significant flash flooding took place on June 18th as 3-5” of rain fell over the course of 4 hours. Roads were covered in several feet of water as people became stranded resulting in 15 water rescues. After yet another heavy rain event on the 21st-22nd produced 2-3” this time in both Rockford and Chicago, the month ended with more flash flooding and even some tornadoes on the 26th.
— First Warn Weather (@FirstWarnWX) June 27, 2018
Northern spots were deluged with an additional 2-4” of rain as 3 tornadoes developed over the area. Luckily, little damage was associated with the severe weather as only one tornado, which traveled through Manhattan IL, was confirmed as an EF-1. With wind speeds up to 95mph, the brief tornado resulted in snapped tree branches and displaced roof shingles. When all was said and done, Chicago ended the month 4” above average for a total of 7.6” of rain. Not surprisingly, after all that rain, June was deemed the wettest month on record in Rockford which finished with over 14” of rain for the month (almost 10” above normal).
— Gumbumper (@Gumbumper) June 27, 2018
In the Ohio River Valley, temperatures for June ended above average thanks to a few heat waves. The first began in Indianapolis as temperatures rose into the 90s from the 7th-9th but it wasn’t until the 16th-19th that a potent heat wave erupted over the entire area bringing daily heat indices into the low 100s. Cincinnati actually had an entire week where temperatures climbed into the 90s from the 15th-20th. Then, similarly to Rockford and Chicago, a final burst of heat on the 29th and 30th pushed temperatures back into the 90s to end the month.
Precipitation throughout June was quite sporadic as we had multiple rounds of showers and storms. This was the result of a few stubborn stationary fronts that set up over the region and proceeded to meander back and forth for up to a week at times, triggering various bouts of rain. On June 8th Indianapolis saw a bit of severe weather when a strong storm prompted hail to fall. However, the largest hail was found northeast of the city in Madison county where 1.75” hail was observed. Then, in various storms on the 9th and 10th, the city saw a few rogue wind gusts near 50mph. Due to a nearly stationary front, Columbus saw 5 consecutive days with measurable precipitation from the 19th-23rd which ultimately prompted the area to see above average totals for June (total of 6.7”, about 2” above normal). Otherwise, Indianapolis, Dayton and Cincinnati ended below average for precipitation with Cincinnati observing a full 7 days without any measurable rainfall from the 14th-20th.