UPDATE 9:15PM: Little or no change to the 4:30PM post. Precipitation from the winter storm centered over the southern Plains is on track to arrive in Chicago between 9AM and 1PM Tuesday. Two to six inches of heavy, wet snow is expected to accumulate over northeast Illinois by Wednesday morning. Most of that snow will fall between 3PM and 8PM, which will have a significant impact on the afternoon/evening rush hour.
United Airlines has already canceled some flights in and out Chicago's O'Hare Airport for Tuesday afternoon and evening.
A Winter Storm Watch remains in effect from Noon until 9PM Tuesday for most of the Chicago area.
BELOW: Forecast map for 12:30PM and 4:30PM Tuesday. Transition from rain, or a rain-snow mix, should be complete by 4PM with the potential for heavy snow during the evening rush.
4:30PM: A powerful Winter storm continues to churn through the southern Plains this afternoon. This storm will impact the Chicago area on Tuesday afternoon and evening with a wintry mix to start, changing over to bursts of heavy snow by late in the day.
Here is the very latest on Tuesday's storm:
- The precipitation is expected to start between 11AM and 3PM. The morning rush hour will not be impacted, but the same cannot be said for the afternoon rush when bursts of heavy snow will be possible.
-Due to a warm layer aloft, the precipitation will begin as a mixture of snow, sleet and rain, changing over to all snow by late afternoon.
-Total snow accumulation between two and six inches is expected by 6AM Wednesday morning.
-Winter Storm Watches have been cancelled for southern Wisconsin, northern Indiana, southern Michigan and northwest Illinois.
-A Winter Storm Watch continues for northeast Illinois including Chicago. Although total snowfall accumulation will not be extreme, a couple hours of heavy snow combined with powerful wind gusts of 40 to 48mph may make the evening commute very difficult.
BELOW: National Weather Service winter weather advisories, watches and warnings as of 4PM Monday.