‘Arctic Superfront’ deals coldest core today

Ever wonder what -26 looks like on Lake Superior at Grand Marais? Thanks to photographer Bryan Hansel for passing along this amazing shot of the lighthouse at Grand Marais this morning.

They say a picture is worth a thousand words. If so, we may have to bleep a few of the utterances from this shot. To my eye, it captures perfectly the essence of Minnesota's latest arctic invasion.

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Headlines: What you need to know first Monday morning

• The core of the coldest air passes over Minnesota Monday.

• Wind chill warnings are in effect until noon Tuesday

• -40 to -65 wind chills  in Minnesota Monday

• 5 minutes - time it takes exposed skin to freeze at -50 wind chill

• -20 and -27 in the inner metro urban core and suburbs Monday and Tuesday morning.

• -27 degrees record low temp at MSP Monday morning (We have a shot, but my hunch is we'll stop short of the record.)

• -13 degrees  daytime high in the metro Monday

• -14 degrees record lowest maximum temperature Monday (set in 1909)

Bottom Line: The eventual low temps is interesting for the record books, but largely academic overall. It's still going to be dangerously cold with wind chills in the -40 to -60 range. At -50 wind chill, your skin can freeze in just 5 minutes. Take this cold in stride, but with appropriate respect.

Super Arctic

Sunday was plenty cold, but a secondary sort of 'Super Arctic' front feeds the Mother Lode of arctic cold down over Minnesota by Monday.

You know it's cold when temps don't crack -25 during the daytime.

Look at temps at 1 pm Sunday west of Lake Winnipeg near the coldest core of the incoming arctic air mass. Here's a look at surface temps from the University of Illinois.

Train 486?

The coldest core of sub-zero air passes through Minnesota early Monday. One way meteorologists gauge the incoming cold wave is to look at the 'thickness' level between the surface and 500 millibars, which is usually about 18,000 feet up. The model output with incoming air mass show a thickness core below 486 decameters over Minnesota early Monday morning.

That means the 500 millibar thickness is close to 15,945 feet. Translation? The compressed atmosphere coming into Minnesota is very, very cold. I haven't seen an air mass with 'thickness values' that low in many years in Minnesota.

Here's a closer look at the cold core coming into Minnesota courtesy of the Twin Cities NWS.

'Life-Threatening'

The Twin Cities NWS is pulling no punches in describing the incoming air mass.

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN

1014 AM CST SUN JAN 5 2014

...HISTORIC AND LIFE-THREATENING COLD AIR HAS ARRIVED...

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

.A WIND CHILL WARNING REMAINS IN EFFECT FOR CENTRAL AND SOUTHERN MINNESOTA AND WEST CENTRAL WISCONSIN THROUGH NOON TUESDAY.

THE COLDEST AIRMASS SINCE 1996 IS MOVING INTO THE REGION AND WILL BE WITH US INTO TUESDAY. WIND CHILL VALUES TODAY WILL RANGE FROM 30 BELOW TO 45 BELOW ZERO. TEMPERATURES TONIGHT WILL BOTTOM OUT IN THE 20S AND 30S BELOW ZERO WITH ONLY A SMALL RECOVERY ON MONDAY. THE ARCTIC COLD TONIGHT AND MONDAY WILL BE ACCOMPANIED BY BRISK NORTHWEST WINDS. THE COMBINATION OF THE COLD AND WIND WILL PRODUCE WIND CHILLS OF 50 BELOW TO 65 DEGREES BELOW.

THIS IS A LIFE THREATENING SITUATION IF YOU BECOME STRANDED. WIND CHILLS COLDER THAN 50 BELOW CAN CAUSE EXPOSED FLESH TO FREEZE IN ONLY 5 MINUTES. COVER AS MUCH FLESH AS POSSIBLE WHEN VENTURING OUT OVER THE NEXT FEW DAYS.

You don't see this often. A rare 'PDS' Wind Chill Warning?

...WIND CHILL WARNING REMAINS IN EFFECT UNTIL NOON CST TUESDAY...

* THIS IS A PARTICULARLY DANGEROUS SITUATION.

* WIND CHILL VALUES: 35 TO 65 BELOW...WITH THE COLDEST READINGS TONIGHT AND MONDAY MORNING.

* IMPACTS: EXPOSED FLESH WILL FREEZE IN 10 MINUTES WITH WIND CHILLS OF 35 BELOW...AND IN 5 MINUTES WITH WIND CHILLS OF 50 BELOW OR COLDER.

* OTHER IMPACTS...WINDS GUSTING BETWEEN 35 AND 45 MPH THIS AFTERNOON AND TONIGHT WILL LEAD TO BLOWING SNOW WITH VISIBILITIES OCCASIONALLY DROPPING TO 1/2 MILE OR LESS IN NEAR BLIZZARD CONDITIONS. SHOULD YOUR VEHICLE BECOME STRANDED...YOUR LIFE WILL BE AT RISK. CONSIDER POSTPONING ALL TRAVEL.

Arctic air penetrates deep

Take a look at the huge territory under wind chill advisories and warnings from the NWS.

How your body reacts to extreme cold

Here's a nice graphic form the NWS that shows how cold affects us, and how to stay well during these bitter arctic outbreaks.

Pattern Change: Major January Thaw next weekend?

Some Minnesotans who may want a respite from the extended cold of the past month may enjoy what looks like a major pattern change ahead. The upper winds will shift, and blow in from the Pacific by next weekend. It's looking more likely that temps may reach the 30s for a few days by next weekend.

Stay safe and warm, and hang in there!