Frigid arctic air is on the move—and it sweeps into Chicago overnight sending temps and wind chills plunging. By morning, Chicago’s temps will have fallen to 0 in the city and wind chills are to dive into the 10 to 20 below range. Wind gusts are to build to 30 mph at time overnight—a bitterly cold weather set-up—one which renders the chill dangerous.

A wind chill advisory kicks in at 11pm tonight and runs through 10 am Friday.

What’s happening late Thursday in Minnesota and the Dakotas is a preview of what’s coming. Temps have dropped sub-zero and wind chills are down to 35-below in northwest MN and parts of North Dakota.

Temps and wind chills drop to 14/0 at 9pm; 7/-10 at midnight and to -1/-17 in the city by daybreak—and Friday’s high will rise to 12—a drop of 21-deg from Thursday’s 33 -deg high.

Chicagoans basked in 100% of the city’s possible sun for a second day—a treat after a record cloudy January.

Sub-freezing temps will cover 80% of the Lower 48 by morning—but will by Sunday afternoon shrink to just 10% of the country.

The incoming cold blast will be brief—and will yield to an extended period of late winter above normal temps. This week is to come in 8-deg below normal—but the HUGE PATTERN CHANGE means next week’s temps will average an eyecatching 20-deg warmer and more than 10-deg above normal—with many 40-deg daytime highs.

In fact, current modeling had each of the coming 15 days AFTER FRIDAY surging 8 to 15-deg above normal.

Latest Metro Forecast

WIND CHILL ADVISORY from 11pm tonight through 10 am Friday morning

TONIGHT: Windy and turning sharply colder. Scattered clouds with wind gusts building to 30 mph at time producing a dangerous level of chill. More clouds and a few flurries possible downwind of Lake Michigan in northwest Indiana.Temps plunge to 4 above to 2-below in the city by morning and to 4 to 8-below coldest northwest suburban locations. Wind chills by daybreak drop to 10-below to 20-below.

FRIDAY: Mostly sunny but quite cold. Gusty morning winds ease in the afternoon—but Friday highs only reach 12-deg.

FRIDAY NIGHT: Partly cloudy and cold—but with steady or rising temps late. Low 10 in the city; single digits northwest—but rising into the teens by morning.

SATURDAY: Clouds move in, becoming windy and noticeably milder. High 21-deg warmer than Friday—reaching 37 Saturday afternoon.

SUNDAY: Partly sunny, windy and milder. High 41.

MONDAY: Becoming cloudy, breezy and quite mild for the season. High 48.

MONDAY NIGHT: Chance of rain showers Monday night.

TUESDAY: More cloudy than not, still mild but less windy. High 49.

WEDNESDAY and THURSDAY: Growing prospects for rain. Temps remain above normal. High Wednesday 41..lower lakeshore. Thursday’s high 43.