A combination of very cold air aloft moving atop Lake Erie and Superior—which have water temperatures in the mid-30s to low 40s, with a disturbance aloft in the atmosphere, a lake-effect snow band is expected to set from Cleveland to Pittsburgh which could lead to some brief visibility reduction along with a narrow zone of accumulations.

Meteorologist Scott Gagliardi said after a little snow Friday night, bitterly cold temperatures arrive for the weekend. Here's his Friday 7:20 a.m. forecast.

Winter officially arrives at 4:21 a.m. on Saturday, and Mother Nature is not wasting any time. We’re getting a robust influx of frigid arctic air that’s going to take temperatures way down and ramp up a biting northwest wind.

National Weather Service officials are expecting snow to continue throughout Friday with daytime accumulation of at least an inch. Officials said snowfall will continue all across northern Illinois and northwest Indiana until about 5 p.

Snow is expected to fall around Indianapolis for a couple of hours after what started as a light rain early Friday morning turned into light snow showers about 10 a.m. Central Indianapolis can expect up to an inch of accumulation,