Editor's Note: Many parts of the Chicago area were under severe thunderstorm warnings Tuesday morning. A severe thunderstorm watch continued for all parts of the area through 11 a.m. At Chicago O'Hare International Airport, a ground stop and ground delay was in effect through 8:45 a.m. Weather warnings and watches can be found here.
Some parts of the Chicago area saw severe thunderstorm warnings overnight, with more rounds of strong to severe storms expected to develop Tuesday, beginning with the morning commute.
"We're tracking the potential for two rounds of storms," NBC 5 Meteorologist Alicia Roman said. "First in the mid-morning, where we could see gusty, damaging winds and torrential downpours. And then in the late afternoon, the severe risk continues."
STORM TIMING: What to expect and when as severe thunderstorms sweep through Chicago
Overnight and early Tuesday, a storm moved through Kendall, Will, Kankakee and Grundy counties, though the rest of the Chicago area remained dry.
That wasn't the case as the morning went on. Around 4 a.m. Tuesday, a line of fast-moving thunderstorms was traveling in northwest Illinois and up through Madison, while another system was over eastern Wisconsin and into Michigan.
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"It's moving pretty fast, lots of lightning," Roman said, of the line in northwest Illinois.
In the 5 a.m. hour, the National Weather Service issued a severe thunderstorm watch for the entire Chicago area. The watch would remain in effect until 11 a.m., the NWS said.
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Around 5:30 a.m., a severe thunderstorm warning was issued for parts of Boone and McHenry counties, the NWS said. In the 6 a.m. hour, severe thunderstorm warnings were issued for parts of Cook, DuPage, DeKalb, Kane and Lake counties, the NWS said. Counties to the south were also added, though the watch expired before 8 a.m.
"Hail damage to vehicles is expected," the NWS said in an alert. "Expect wind damage to roofs, siding and trees."
While many weather alerts came to an end by 8 a.m., just minutes later a severe thunderstorm warning was issued for northern Kendall, southern DeKalb and southern Kane counties. That remained in effect until 8:45 a.m.
The chance for showers and storms in the Chicago area increases through the Tuesday morning commute as that line of showers and storms was expected to move over Kane, DeKalb, Lake, McHenry and Northern Cook Counties. By around 10 a.m., those storms were expected to push southward, Roman said.
A second round of storms could ramp back up later Tuesday, Roman said, between 4 p.m. and 6 p.m., creating potentially hazardous conditions for the afternoon and evening commutes.
According to the Storm Prediction Center, counties to the north Tuesday were at a "marginal" risk of severe weather, which ranks as level one of five on the SPC"s five-level scale. The rest of the Chicago area Tuesday was under a "slight" risk of severe weather, which ranked as level two.
"Any storm that does develop could produce heavy downpours and gusty, damaging winds," Roman said.
Those gusty winds could top 70 miles per hour, Roman said. Flash flooding was also possible with Tuesday's storms, along with the threat of quarter-sized hail, Roman added.
In advance of the weather, Chicago's Metropolitan Water Reclamation District issued an “Overflow Action Day” alert, advising Chicago-area residents to use less water in an effort to prevent overflowing of storm water management systems in the region.
Tuesday will also be a hot and humid day with muggier conditions, Roman said. Dewpoints in the 60s and 70s were expected, along with temperatures in the 80s to mid-90s.
"It's quite muggy out there already this morning," Roman said.
According to Roman, heat index levels Tuesday could reach into the upper 90s.
