Chicago snow timeline: Winter Weather Advisory bears down

Lake-effect showers, possible snow expected in Chicagoland Mike Caplan has your Chicago weather update! The Brief A Winter Weather Advisory goes into effect at midnight Friday for parts of Will, Cook, and Lake counties. Lake effect rain showers will transition to snow overnight, bringing slushy accumulations mainly east of Interstate 57. Drivers should prepare for reduced visibility and slick elevated roadways through Friday morning. CHICAGO - The season's first snowfall is heading to the Chicago area and northwest Indiana. A Winter Weather Advisory takes effect at midnight across portions of the south and southeast suburbs as a lake-effect weather system shifts from rain to snow, the National Weather Service announced. The advisory will be active from midnight to 10 a.m. Friday for eastern Will County, southern Cook County, and Lake County in Indiana, where meteorologists warn of a possible threat to life or property due to hazardous travel conditions. Snow timeline Timeline: Periods of lake-effect snow are expected to develop late Thursday night and continue into Friday morning. Thursday afternoon: Blustery conditions bring mainly lake-effect rain showers drifting across northeast Illinois and northwest Indiana, extending well inland. Daytime highs reach the mid-40s. Late Thursday night through Friday morning: As temperatures drop into the upper 20s and mid-30s, lake-effect bands focus near and east of the Illinois-Indiana state line. Precipitation switches over to mainly snow with localized slushy accumulations probable. Friday afternoon and early evening: Daytime highs reach 40 to 44 degrees, shifting precipitation back to mainly rain. Friday night into Saturday morning: Overnight lows dip between 22 and 34 degrees, triggering another brief transition back to lake-effect snow showers, primarily in northwest Indiana. Saturday afternoon through Monday: Dry conditions return with highs climbing from the mid-40s on Saturday to near 51 degrees by Monday. What we know: According to National Weather Service graphics, the highest potential for slushy snow accumulations sits mainly east of Interstate 57 and near or north of the Kankakee River. Meanwhile, warmer lake temperatures are expected to keep precipitation falling predominantly as rain right along the immediate lake shore. Motorists traveling near and east of Interstate 55 can expect slowed travel, reduced visibility, and slushy coatings—particularly on bridges, overpasses, and other elevated roadways. Featured article When is the first average snowfall in Chicago? Fall may have just begun, but the first snow is likely just around the corner in Chicagoland. What we don't know: The NWS said confidence remains low regarding the exact time precipitation will change over from rain to snow. Additionally, the precise geographic track of the lake effect snow band is expected to wobble at times overnight, meaning exact snowfall totals could vary sharply over short distances. The Source: The information in this report came from the National Weather Service. Winter Weather Chicago News