Slightly milder Thursday, then dangerous cold for the New Year

A weak system brings a dusting of snow across Minnesota Thursday and briefly milder temperatures, but the colder air behind that disturbance starts a pattern that brings bitter cold.

Thursday’s forecast

Compared to Wednesday, Thursday is off to a much milder start, despite much of northern Minnesota being below zero. Morning temperatures range from few negative teens northwest to mostly single-digits (above zero) south.

However, with the negative teens northwest and light winds, wind chills in northwestern Minnesota are in the negative 20s and occasionally 30s, prompting a wind chill advisory in that area until noon.

Much of the reason for the relatively milder weather Thursday is because a disturbance is moving across the state. It is causing some light areas of snow around the state, most of which stays north, but even the Twin Cities has had a little light snow as of 7 a.m. snowfall is expected to remain under an inch through the day.

That disturbance also moved a few more clouds in, allowing less overnight cooling, and brought in a milder wind flow from the southeast, especially in southern Minnesota.

During the day, that milder wind pattern will help southern Minnesota warm back to seasonable highs in the 20s, while northwestern Minnesota remains slightly below average with single digits and a few negative highs.

Dangerous weekend cold

The brief return to seasonable weather does not last long. Already from late Thursday to early Friday, a cold front starts moving colder air back across the state, and a frigid pattern with winds from the north to northwest then persists into early Sunday.

By Friday, that means temperatures will budge little during the day and will even fall slightly by the afternoon in a couple of spots. Temperatures both Friday morning and afternoon will generally range from the negative teens northwest to “positive” teens southeast.

There will also be another very light dusting of snow in southern Minnesota during the day Friday.

Friday night the snow is over, skies clear, and that is when temperatures really begin to dive. All of Minnesota will be back below zero by Saturday morning, and the northwestern third of the state in likely to be 20 below or colder. The entire state is likely to remain below zero all of New Years Day, putting temperatures 15 to 25 degrees below average.

Here is a chart that includes northeastern Minnesota and how the temperatures compare to averages:

It also highlights the dangerous level of the wind chills at 30 to 45 below for that area.

Winds chill will be dangerously cold across the state over the weekend and are forecast to be even more frigid in many areas Sunday morning because that is when temperatures will be at their coldest for the majority of the state.

Other than a few negative teens south and near Lake Superior, air temperatures Sunday morning will mostly be 20 below or colder. Adding in the wind chill, it is probable that wind chills will be minus 20 to minus 40 most of Saturday night into Sunday morning with some areas that could see wind chills dip to near 50 below.

Wind chill advisories and warnings are expected to be issued for much of the weekend.

Finally, Sunday morning a more southerly wind flow is expected to prevail, bringing most of Minnesota back above zero. Monday is even milder, returning seasonable temperatures back to the state, ranging from single-digit highs north to 20s south.

Here is that temperature trend for the Twin Cities showing the big plummet, then the return to “normal” January cold:

Programming note

You can hear my live weather updates on Minnesota Public Radio at 7:49 a.m. Monday through Friday morning.