Slow-moving storm to drop ice, sleet, snow and rain across Minnesota

You know that old saying — “just wait 15 minutes” — for different weather?

Get ready for a smorgasbord of wintry precipitation types this weekend across Minnesota. Winter weather watches and warnings are flying across the Upper Midwest this week.

Here are a few National Weather Service office links to follow the wide array of warnings:

Right off the top, there are a couple of factors that make this system unique and will affect the type and duration of weather you see out your window this week.

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This is a big, complex, multiphase system that will cover the Upper Midwest with different precipitation types at different times.
This is a slow-moving system that will spin over our area into the weekend.
The freezing line will hover around and north of the Twin Cities through Wednesday, bringing multiple precipitation types.

Let’s break down this Frankenstein monster storm this week.

The system

This potent low-pressure system is the same one that dumped almost 6 feet of snow in the Sierra Mountains out West.

The system will spin into our region Tuesday, then stall for most of this week.

The National Oceanic and Atmospheric Administration’s Global Forecast System model gives you the big picture of a slow-moving system into Saturday. The initial rain, ice, and snow waves hit Tuesday, then the system produces intermittent precipitation that trends toward mostly snow showers later this week into Saturday.

NOAA GFS model Saturday — NOAA GFS model Tuesday into Saturday.
NOAA, via Tropical Tidbits

Mixed bag Tuesday and Wednesday

Icy precipitation begins around or after midnight overnight Monday in southwestern Minnesota and spreads northeast through Tuesday. Note how an icy mix of possible sleet and snow changes to rain across the Twin Cities by late Tuesday.

NOAA NAM 3 km model — NOAA North American Mesoscale Forecast System 3 km model
NOAA, via Pivotal Weather

Ice storm potential

Ice accumulations could exceed one-quarter inch in eastern South Dakota and southwestern Minnesota around Luverne, Pipestone, Worthington, and areas in between.

Ice storm warnings are up for parts of eastern South Dakota.

Snowfall totals into Thursday

Because the freezing line is likely to hover north of the Twin Cities most of Tuesday into Wednesday, it looks like rainfall will cut snowfall totals around the greater Twin Cities through Wednesday.

The heaviest snow early in the storm will run from the Dakotas through central Minnesota to the North Shore.

Here’s NOAA’s Global Forecast System model snowfall output through 6 a.m. Thursday:

NOAA GFS snowfall output by Thursday morning.
NOAA, via Pivotal Weather

Prolific North Shore snowfall totals?

Persistent easterly wind fetches across Lake Superior with this system will enhance snowfall totals along the North Shore. Several forecast models conservatively exceed 1 foot of snow this week. And a few are pumping out more than 2 feet of snow locally.

Check out these prolific snowfall totals along the North Shore from the Canadian model this week.

Canadian model snowfall output 2 — Canadian model snowfall output for the North Shore area by Sunday.
Environment Canada, via Pivotal Weather

Phase ll: Mostly snow Thursday into Saturday

Colder air will work in behind the system as it stalls and swirls over Wisconsin Thursday into Saturday. That means periods of snow showers that will add up to inches over time for most of Minnesota.