Sub-Zero: Polar Vortex surges south this week

Congratulations Twin Cities. You've just experienced your first sub-zero temperature of the winter season.

The mercury dipped just below zero around 7:40 am today at MSP Airport.

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Graphic: FAA/NOAA

It's the first of several sub-zero mornings ahead in the next week across Minnesota. Temperatures hover a few degrees either side of zero this week, then the season's coldest sub-zero air mass so far surges south next weekend.

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  • 11.8" season to date snowfall at MSP Airport

  • -2.6" vs. average through December 11th

  • 5.2" season snowfall total one year ago

  • +2.0 degrees - December temps vs. average so far this month

Snow cover increases

Snow cover across the Upper Midwest took a big step forward with last weekend's snow event. Snow cover now extends through Des Moines to south of Chicago. It's not going anywhere anytime soon.

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NOAA

Here's the final snowfall tally for southern Minnesota from the Twin Cities NWS. Redwood Falls takes the coveted Golden Snow Shovel Award with a fresh foot of powder.

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Twin Cities NWS

PM snow shot

A weak Clipper sails through central Minnesota again this afternoon. Look for one more shot of magic fairy dust to hit during afternoon rush hour. Snowfall should generally be an inch or less, but with temperatures hovering around 10 degrees MNDOT road salt won't be as effective. That means roads will slick up again late this afternoon and evening. How lovely.

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Cold week

Temps run about 15 degrees colder than average this week across Minnesota. Highs stagger above zero in the Twin Cities during the day, and dip into the single digits below zero at night. Here's the forecast at a glance for the metro this week.

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Graphic: Twin Cities NWS

Friday snow

After today's late afternoon and evening dusting, the next significant chance for snow arrives Friday.

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Our next low pressure storm tracks south of Minnesota Friday and Saturday. It should be cold enough for all snow across southern Minnesota.

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NOAA GFS via tropicaltidbits.com

Don't take this to the bank yet. It's still to early to express snow totals and coverage with decent confidence. But the GFS model snowfall for Friday and Saturday supports the notion of several more inches somewhere across southern Minnesota, Iowa and Wisconsin this weekend.

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NOAA GFS snowfall via tropicaltidbits.com

Snow lovers rejoice. Stay tuned.

Polar vortex arrives by Sunday

The coldest air mass in nearly 3 years looks set to surge south into Minnesota this weekend. We can track the source of the air mass, all the way to Santa and the North Pole.

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NOAA GFS upper air map via tropicaltidbits.com

The Arctic front blows through Minnesota Saturday. Temps plunge into the -20s to -30 by Sunday morning.

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NOAA GFS 2-meter temps via tropicaltidbits.com

I don't know if we'll hit -23 at MSP yet, but -20 looks very doable with this inbound air mass Sunday morning. If we do hit -23 it will be the coldest in nearly 3 years since we hit -23 on January 6th, 2014.

Glancing blow

This Polar Vortex shot appears to be progressive and will keep moving east away from Minnesota next week. It appears the core of the bitterly cold air won't stay more than about 48 hours. Temperatures should moderate back to above average by the middle of next week, as temps in the 20s and 30s above zero return in the week leading up to Christmas.

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NOAA GFS output via IPS Meteostar

Stay tuned.