Winter Weather Advisory for 2 to 4 inches of lake-effect snow in northwest Indiana this evening – frigid cold sets in Chicago-area-wide tonight
Update 4:45PM CST…
A Winter Weather Advisory is in effect this evening until 9PM CST for Porter County and Midnight CST for Lake County in Indiana. Accumulating lake-effect snow will continue across northern portions of Lake and Porter Counties in northwest Indiana this evening, laying down an additional 2 to 4-inches in some locations. Snow showers should weaken and possibly drift back across the border into Illinois, just south of Chicago late tonight.
Under the influence of arctic-cold high pressure and diminishing winds over a thick fresh snow cover, clear skies will allow temperatures to fall quickly this evening in northeast Illinois – dropping below zero before midnight in many areas. By Monday morning overnight lows will probably range between near zero in downtown Chicago to 10 to 15-degrees below zero far north and along and west of the Fox River Valley. Some cloudiness could spread over the area modifying temperatures somewhat toward morning. With northerly winds 5 to 12 mph, wind chills overnight could drop to as low as the -10 to -25-degree range across northeast Illinois and 5 to 10-below in northwest Indiana.
Update 10AM CST…
The Winter Weather Advisory has ended for Cook County, Illinois as the lake-effect snow has moved into the northern part of Lake County, Indiana where snow is falling at times as much as over an inch per hour. A Winter Storm warning/Advisory for at least an additional 3 to 7-inches of snow have been issued for Lake and Porter Counties respectively in Indiana until later this afternoon. Travel is slow and dangerous with gusty north winds causing blowing and drifting.
Most of the snowfall will be concentrated in the northernmost portions of these two counties along and just inland of the Lake Michigan shoreline. Snow tapers off quickly to the south. Snow showers may continue later this afternoon into the evening, but weaken considerably.
Northerly winds gusting to 30 mph will continue the development of a plume/bands of snow to develop over Lake Michigan and train south into the Cook County, Illinois this morning and Lake and Porter Counties, Indiana today. Accumulations in Cook County appear to be concentrated along and just inland where 2 to 5-inches is still possible this morning with lighter snow into adjoining Will County.
As winds become more northwesterly, the bands of snow will swing east , concentrating on Lake and eventually Porter Counties in Indiana well into the afternoon with localized accumulations of 3 to 7-inches possible. Lesser accumulations may work farther south into adjoining Newton and Jasper Counties. Snow Showers should weaken later today.
A Lakeshore Flood Warning will be in effect this morning for Lake and Cook County, Illinois and Lake County, Indiana shoreline this morning where 7 to 10-foot waves may cause minor flooding.
Another weather factor this morning is the arrival of single-digit cold temperatures which along with the gusty winds will cause wind chills in the -5 to -15-degrees range.
Below is a Regional Weather Radar displaying the snow plume/bands…