Winter Storm Update

6:01 PM Friday, December 3, 2021

A Winter Storm Watch remains in effect from late Saturday night through late Sunday night for northern and northeastern Minnesota and for parts of northwest Wisconsin.

  • Snow is expected to move into western/southern portions of the Northland Saturday evening with snow spreading northeast overnight through Sunday morning.
  • Snow continues during the day Sunday (heaviest across the north).
  • Lake enhanced snowfall is possible along the North Shore on Sunday as winds will be out of the southeast. Lake enhanced snow chances are highest mainly northeast of Two Harbors on Sunday.
  • Snow tapers off from west to east late Sunday night/Monday morning, but lake effect snow is possible along the South Shore impacting portions of Ashland and Iron County on Monday.
  • Southeast winds may gust to 25 mph in parts of the Northland, especially along the North Shore on Sunday, and then winds will shift to the north/west Sunday night and Monday with wind gusts of 15 to 30 mph possible during that time. The gusty winds may produce areas of blowing and drifting snow Sunday into Monday morning.
  • High temperatures on Sunday are forecast to range from the middle to upper 20s in northern Minnesota to the low to mid 30s in east-central Minnesota and northwest Wisconsin, so the snow that falls on Sunday may be on the wet side especially across southern portions of the Northland.
  • Arctic air pours into the Northland next Monday and Tuesday with highs on those days only in the single digits and teens with overnight lows in the single digits, teens and 20s below zero Monday night.

Here’s my preliminary snowfall forecast for Saturday night through Monday.

At the moment the snowfall range for the Twin Ports is from 3″ to 8″, but this range will tighten up (hopefully) by Saturday afternoon.

Note: 44% of Euro ensemble members show snowfall of 6″ or more in Duluth this weekend, with only 20% of GEFS ensemble members showing 6″ or more of snow in Duluth. So, we’ve seen a decrease in those percentages compared to how they looked 24 hours ago.

I do have some concerns with how quick this system moves through, and with how long the strongest lift will remain over the area, and the fact that it has clipper origins which usually isn’t full of deep moisture since the system comes out of western Canada and the Northern Rockies, but for now here’s what I’ve come up with for snowfall totals and will adjust if need be.

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Low pressure is forecast to move east across north-central Montana on Saturday, reaching southeast North Dakota Sunday morning. This low is then expected to move across central Minnesota into northern Wisconsin Sunday afternoon and evening before reaching eastern Lake Superior Monday morning. Note there is a possibility that will see some minor shifts north/south with the storm track over the next 24 hours.

For Duluth and Superior — Snow is expected to begin ~Midnight to 2 AM Sunday with snow continuing throughout the day Sunday and into Sunday night, but snowfall intensities may diminish quite a bit after Sunday morning. Snow comes to an end Monday morning, most likely after 2 AM the way it looks now.

Here’s the 12z European model simulated radar forecast valid from 6 PM Saturday to 6 AM Monday (Snow in blue colors).

Winter Storm Severity Index through 6 PM Sunday, December 5, 2021.

Moderate (orange) to Major (red) winter storm impacts are possible in much of the Northland late Saturday night through Sunday night, with minor winter storm impacts possible in the areas shaded in yellow.

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Although the majority of the computer models are in decent agreement on the track of the low this weekend and on the placement of the heaviest snow band, there are two models that are quite a bit different, and the one I’m showing here is the HRRR model which has support from the RAP model, those two models bring in a lot of warm air, in fact should these solutions verify, then temperatures Sunday afternoon would make a run at 40 degrees if not a little warmer from eastern Minnesota to Duluth and into northwest Wisconsin, while a band of snow lifts further north into far northern Minnesota while the rest of the Northland gets dry slotted for a few hours Sunday afternoon before some light wrap around snow returns Sunday night.

The HRRR and RAP model solutions are the outliers at this time, but you can’t ignore what they are showing just yet, which is why I shared it here.

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The Big Island Summits in Hawaii are under a Blizzard Warning (areas in red on map below) through Sunday with snowfall totals of up to 12 inches possible along with wind gusts greater than 100 mph. Although rare, blizzard warnings in Hawaii have occurred before, with the last one occurring in March 2018.

Tim

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