A little light snow or flurries at Chicago, but an ice storm will be developing downstate

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Thunderstorms accompanied some of Chicago’s rain Wednesday evening, and pea-sized hail fell at Monee in Will county around 530 pm. Thunderstorms in Chicago in January are not especially unusual: 10 of the 20 past Januarys recorded at least one thunderstorm during the month (though, admittedly, the storms were weak: they produced nothing more than a few flashes of lightning).

Rainfall Wednesday late afternoon and evening totaled 0.34” at O’Hare Airport and 0.54” at Midway Airport. This was the heaviest rain in a month. Other area rainfall totals ranged up to 0.69” at Hinsdale and 0.62” at Western Springs.

A high pressure system of Canadian origin will position itself over Wisconsin on Friday and Saturday, providing colder air at Chicago along with a little light snow or flurries. Farther to the south, across central and south Illinois, a significant ice storm will be developing.

Moist and relatively mild air across the southern states from Texas northeast to Kentucky and Tennessee will begin feeding northward on Friday, running above much colder air north of there. Freezing rain and sleet are forecast to occur Friday and Saturday in a broad swath of the nation from northern Texas northeast across Oklahoma, southern Missouri, central and south Illinois, and east across central and south Indiana and Ohio.

It is still too early to forecast ice accumulation totals, but the potential exists for a major ice storm Friday and Saturday.