The National Weather Service said the dense fog warning issued Monday for the entire Chicago region would continue through mid-morning, with visibility less than a mile in parts to the north and west, including Waukegan, Aurora and DeKalb.

The heavy fog led to a grounding at Chicago’s Midway International Airport on Sunday, canceling two dozen flights.

According to the NWS, the dense fog warning will last until 11 a.m. Monday.

“Motorists should remain vigilant and be prepared for sudden loss of visibility,” the NWS warned, with visibility dropping to near zero at times. “Drive slowly and keep your distance from other vehicles.”

Monday morning also started out rainy, Roman said, with a few scattered showers, and there could be drizzle or a brief light shower during the morning drive to work.

According to Roman, it would remain mostly cloudy all day on Monday, with some breaks due to the sun.

But there is a silver lining, Roman said, as temperatures will remain mild and warmer, with highs in the upper 40s to mid 50s.

However, temperatures will drop starting Tuesday, with highs in the upper 30s to near 40°C.

“Much cooler for your Tuesday,” Roman said.

Waves of light snow will also occur Tuesday, Roman said, with the first chance for a light rain-snow mix arriving late Tuesday into Wednesday morning.

Thursday afternoon offers another chance for a wintry mix, Roman said, followed by more chances for thunderstorms Friday morning.

“A lot now, but there’s definitely a chance of snow,” Roman said of the amount of precipitation the area could get.

Colder temperatures move in over the weekend as the winter solstice is celebrated on Saturday, December 21st.

“The first day of winter is Saturday, and it’s definitely going to feel like it, with 30 degrees,” Roman said of Saturday’s forecast.

By Christmas Day, temperatures are expected to rise again, reaching a high of 41 degrees, Roman said.