Cold air is here to stay through the end of the week and lake effect snow will bring impacts to parts of Chicagoland Friday and Saturday. Full forecast :Tomorrow will be similar to today with sunny skies and highs in the mid-teens. Lake effect snow is expected to ramp up late Thursday night or early Friday morning, lasting through Saturday. Accumulations will be heavily dependent on how long the dominant lake effect bands sit over any specific area, but the forecast should become a little clearer as we get closer to it. Lake effect snow will continue through Saturday with highs in the lower 20s.