Alicia Roman has the latest forecast as severe weather looms over the Chicago area.
Editor's Note: Track live weather radar as storms move into your area.
More than 300 flights at O'Hare International Airport were canceled Wednesday morning as the threat of severe thunderstorms bringing the potential for flooding, hail, damaging winds and "torrential rainfall" looms over the Chicago area.
As of 1 p.m. Wednesday, FlyChicago.com reported 329 flights at O'Hare airport canceled, with 293 flights facing delays of 45 minutes or more.
Timing: What to expect, when and where as storms move into Chicago area
According to the NBC 5 Storm Team, the entire Chicagoland area Wednesday can expect to see more scattered showers along with periods of heavy rain and the potential for severe thunderstorms to continue from "morning to afternoon." By 5 a.m., some areas had seen up to two inches of rainfall as a result of overnight scattered thunderstorms and pockets of heavy rainfall, the National Weather Service said in a tweet.
"With storms expected to continue into mid-morning, localized flooding may occur," the tweet continued, adding that more storms are expected Wednesday afternoon and evening.
Local
Flood Watch for Chicago area
According to the National Weather Service, DuPage, Cook and Will Counties in Illinois, along with Lake County in Indiana are all under a flood watch until 7 p.m. Wednesday.
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"Flash flooding caused by excessive rainfall is possible," an alert from the NWS said. "Creeks and streams may rise out of their banks. Flooding may occur in poor drainage and urban areas. Underpasses may be flooded."
According to the Metropolitan Water Reclamation District of Greater Chicago, an “overflow action alert” was issued for the region Tuesday, ahead of the strong-to-severe storms expected to arrive.
MORE: Pritzker issues disaster proclamation for Cook County after severe flooding
Those alerts are issued when flooding is possible and when officials are seeking to limit the amount of water entering storm drains and sewers in the area.
Residents are being asked to delay showers and baths at this time, to wait to run any dishwashers or washing machines, and to flush toilets less frequently in their homes to help alleviate high water levels.
According to the NWS, 'Torrential rainfall' may cause roads to flood, with the "highest flood threat in the Chicago metro area."
Heavy rain expected
The NBC 5 Storm Team reports that between one and three inches of rain has already fallen in some parts, with between one and two more inches on the way. However, thunderstorms could produce additional quick rainfall, Roman added.
"The main threat will be heavy rain that will lead to localized flooding," Roman said of Wednesday's weather.
According to the NBC 5 Storm Team, although scattered showers are expected throughout the morning, much of the heavy rainfall and severe storm potential is expected between 12 p.m. and 7 p.m. By 9 p.m., a few lingering showers may remain in the area, the NBC 5 Storm Team adds.
Temperatures Wednesday are expected to remain on the cooler side, with highs in the low 70s to low 80s.
Severe weather risk
The Storm Prediction Center reports that much of the Chicago area this afternoon has been upgraded to a "slight" risk of severe weather and thunderstorms, which ranks as level two on a five-level scale.
Earlier, the area was at a "marginal" risk, which ranks at level one on the scale.
According to the NWS, in addition to heavy downpours and threats of flash flooding, the storms could bring damaging winds up to 60 miles per hour and quarter-sized hail. Additionally, while a tornado risk remains low, it cannot be ruled out, the NWS says.
