CHICAGO -- Temperatures dropping well below zero combined with northwest winds gusting at times over 30 miles per hour will cause dangerous wind chills of -20 to -30-degrees and even colder across northeast Illinois into northwest Indiana tonight and Friday morning.
Frostbite can occur in 10 to 30-minutes, if skin is exposed to these elements, so when outside dress appropriately.
Temperatures should peak around 20-degrees today and then with the passage of a strong cold front begin to fall through the teens later this afternoon into the single-digits this evening and far below zero later tonight and Friday morning. Winds will be strengthening and shifting northwest gusting at times above 30 miles per hour with the frontal passage, while at the same time snow showers will mix with snow on the ground to cause blowing and drifting that could lower visibility and cause some travel difficulties.
Note on the map below the Wind Chill Advisories (light-blue-shaded areas) for 20 to 30-below wind chills extend back to the northwest into the Dakotas, interspersed with Winter Weather Advisories (purple-shaded) and even Blizzard Warnings (red-shaded areas) issued for blowing and drifting snow that could drop visibility to near zero in those areas at times today.