National Weather Service United States Department of Commerce

Moderate to heavy rains will continue to affect central and southeast Illinois through the evening. Colder air will change rain to freezing rain in NW Illinois.
Winter Weather Advisory has been issued for a large portion of the state for the overnight hours, also potentially affecting the mornings commute. After sunset, a wintry mix dominated by freezing rain will settle into the state from the northwest, spreading to Interstate 55 by midnight. Amounts of ice should remain under a couple of tenths, with most places seeing up to a tenth of an inch of ice by morning. Precipitation will end from the northwest to the southeast after about 3 am. Periods of showers and thunderstorms will continue before that, with up to 2 inches more of rain falling in the southeast. As a result, a Flood Watch through tomorrow morning.
A strong cold front will move across the area tonight bringing the threat for a period of freezing rain, sleet and snow to areas west of I-55 this evening, with the transition to a wintry mix edging east of I-55 after Midnight. It appears with temperatures today well into the 50s and 60s and periods of rain, any transition to a wintry mix will be confined to the far western portion of the precipitation shield early on. As a result, most ice accumulations should be a tenth of an inch or less. However, that will be enough to produce some slippery roadways, especially on the lesser traveled roads, bridge decks and overpasses.
A strong cold front will continue to surge into east central IL. Temperatures will drop 20 to 25 degrees quickly after the front passes, along with gusty northwest winds and moderate to heavy rain. The front will reach Effingham by 6 pm and Lawrenceville by 8 pm.