Editor's Note: As of 5:56 a.m., Chicago O'Hare International Airport issued a ground stop due to thunderstorms. The ground stop will continue until at least 7:45 a.m., the Federal Aviation Administration said. At Midway Airport, flights were being held until 7:30 a.m. Our original story continues below.
Heavy rain and hail pummeled parts of the Chicago area overnight, with more rain and storms set to continue throughout the Thursday morning and evening hours.
According to the National Weather Service, a severe thunderstorm warning was issued for parts of Kankakee County until 8 a.m., and in Newton County in Indiana until 8:30 a.m. A severe thunderstorm watch for in Grundy, Iroquois, LaSalle and Livingston Counties continues through 10 a.m.
"Storms are occurring across the area this AM," a tweet from the agency said. "While most storms will be sub-severe, a line of storms may produce strong to damaging wind gusts south of I-80."
NBC 5 Storm Team Meteorologist Kevin Jeanes noted that some parts along I-80 may have woken overnight to the sound of thunder or hail.
"Some of you may have been woken up by hail outside," Jeanes said, noting that as of 5:15 a.m., most of it had moved out. "There still could be some small hail, you can't rule that out this morning, with heavy rain, lightning and thunder."
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Jeanes noted that lower pressure further southwest will continue to track east, bringing with it rotating thunderstorms and potentially more hail. In an alert, the NWS noted that Nickle-sized hail was already reported in Livingston, LaSalle, Kankakee and Will Counties.
In parts of Kansas and Missouri, "gorilla" hail was reported.
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Heavy, widespread rain is expected to fill in through the morning commute, continuing through mid-morning, Jeanes said. Some localized flooding or ponding could occur.
"Plan for rain that could be heavy at times, especially if you get on the road in 1-2 hours from now, Jeanes said in the 5 a.m. hour., noting that roads were already wet.
NBC 5 Traffic Reporter Kye Martin added that the "rough" commute was expected to continue.
At 7:45 a.m., the Metropolitan Water Reclamation District of Greater Chicago issued an Overflow Action Alert, and advised residents to conserve water due to heavy rain.
The threat of stronger morning thunderstorms was expected to stay south of I-80, Jeanes said, though heavy rain, frequent lightning and thunder could be expected areawide.
A break in the rain could arrive through Thursday afternoon, Jeanes said, though storms were likely to pick back up around 3 p.m. and last through the evening.
"There could be a couple strong thunderstorms later on today," Jeanes said, of the forecast.
According to the NWS, storms that occur are expected to contain heavy downpours, lightning, hail and damaging winds of up to 60 miles per hour. A few severe storms could form mainly south of the Illinois and Kankakee Rivers, the NWS said. Further north, severe weather is less likely, the NWS added.
A wide temperature range was also expected for Thursday. South of I-80, temperatures were expected to remain warm, with highs in the mid 60s. To the north and along the lakefront, temperatures were expected to be cooler, with highs reaching only into the lower to mid 40s.
You can find the extended forecast for Chicago from the NBC 5 Storm Team here.
