Residents of Chicago should brace themselves for a winter storm that could bring rain, sleet, and snow to the city over the next few days, potentially causing travel issues and floods.
The National Weather Service has issued a winter storm warning for the following Illinois counties: La Salle, Kendall, Grundy, Kankakee, Livingston, portions of Cook, and portions of Will, beginning early Thursday morning and lasting into the evening. Also in Indiana, Lake and Porter Counties were on the alert list.
Thursday, from 3 a.m. to 9 p.m., there will be a tornado watch in effect.
A period of freezing rain and sleet accumulation is predicted for late Wednesday night through early Thursday morning, according to the advisory. Rain and sleet could change into heavy snowfall by Thursday afternoon, accumulating between 1 and 8 inches.
Wind gusts of up to 40 mph are expected to accompany more than an inch of snowfall per hour at periods Thursday afternoon in Chicago, officials say.
Additionally, a winter storm watch was issued for the following Illinois and Indiana counties: DeKalb; Kane; DuPage; Cook; LaSalle; Kendall; Grundy; Will; and Kankakee; as well as Lake; Porter; LaPorte; Newton; and Jasper.
From 9 a.m. to 6 p.m. on Wednesday, a wind advisory will be in effect for DuPage, Lake, Porter, Newton, and Jasper Counties in Indiana as well as sections of Cook and Will Counties in Illinois.
In certain areas, gusts of up to 50mph are possible, according to the weather service’s advisory. According to the National Weather Service, small tree branches may be blown down and power outages may occur.
Highs in the mid-40s to low-50s are forecast for Wednesday, with temperatures starting out above average.
Rain will begin to fall across the region Wednesday afternoon and into the evening, causing flooding risks in low-lying regions and along river and streambanks. Even more flooding problems could arise as a result of the rain and warm temperatures, which could break up ice jams.
The National Weather Service has issued a flash flood watch for Newton and Jasper counties in Indiana, but heavy rain is predicted across the state, especially south of Interstate 80.
Depending on how rapidly temperatures begin to decrease, that rain could continue through Thursday morning. It will be midnight before the temperature reaches its maximum for the day, and readings will continue to fall throughout the day, transforming the precipitation into ice and eventually snow by Thursday night.
Forecasters warn of the possibility of freezing rain and sleet during Thursday’s morning commute, so drivers should exercise caution.
The most dangerous parts of the storm are still to come. Wednesday’s storm is forecast to travel fast from the Great Plains, but the path it takes will decide how soon the precipitation changes from rain to snow, and then how much snow could fall in some areas of the Chicago region.
There may be some accumulation of snow on Thursday if a northerly path is taken by the storm. Moisture from Lake Michigan, which could contribute to lake-enhancement, may increase snowfall in the city and the northern and western suburbs of Chicago.
When a storm moves further south, it could have a more direct impact on parts of central Illinois and Indiana. An extended period of heavy rain or snow might fall on Kankakee County and sections of northwest Indiana as well as the far southern suburbs.
There is a good chance that at least some snow will fall in the Chicago region on Thursday, with icy and windy conditions making for dangerous driving conditions.
Finally, substantial lakefront flooding in Illinois and northwest Indiana could emerge as a new concern. On Wednesday and Thursday, strong northerly winds are predicted, posing a threat to low-lying regions near the water and the potential for large waves.
Conditions are expected to clear by Friday, and the weekend will begin with temperatures far below zero.