A mix of freezing drizzle and snow possible Wednesday night-Thursday, winter storm watch issued for parts of northwest Wisconsin; arctic blast on the way this weekend into next week

A complex setup on the way for Thursday with the computer models pretty much in two camps today, one camp paints a rather snowy picture for eastern Minnesota and northern Wisconsin for Thursday, while the other camp keeps the bulk of the snow farther east affecting central/eastern Wisconsin and upper Michigan. The differences seem to hinge on how quick a cold front moves through the area, and how soon an upper level trough can take on a negative tilt, if it happens earlier that would probably increase the chances for a more significant snow event in eastern Minnesota/northern Wisconsin Thursday, but if it happens later, then most of the snow would fall farther to the east.

  • HRRR, NAM, RAP, UK, German-Icon models and to some extent the GFS are the snowy models keeping things a little farther west, enough so where it would also affect Duluth and Superior.
  • Euro and the Canadian models show the bulk of the snow falling farther to the east, with only a light snowfall event (if that) farther west including for eastern Minnesota and the Twin Ports.
  • The light blue outlined area on the map below could shift west by about 50-75 miles, or slightly more to the east over the next 24 hours.

There is a chance for some freezing drizzle across the Northland Wednesday evening into early Thursday morning with ice accumulations mostly in the trace to less than 0.05″ range, not a major icing event, but only small amounts of ice can create difficult travel conditons.

Source: https://weathermodels.com/

A Winter Storm Watch has been issued for parts of Wisconsin (blue area on map)

In the Northland – A Winter Storm Watch is in effect from late Wednesday night through early Friday morning including the counties of Bayfield, Ashland and Iron in northwest Wisconsin. Some cities included in the watch are Bayfield, Washburn, Ashland, Butternut, Gile, Hurley and Upson.

Significant snow accumulations and a wintry mix of precipitation is possible in the watch area. Travel could be very difficult, and the hazardous conditions could impact the Thursday commutes and also the Friday morning commute.

My preliminary snowfall forecast is leaning more toward an easterly trend to the most significant snowfall on Thursday with amounts of 3 to 6 inches or more possible generally east of a Hayward-Ashland line.

Note: At the moment I’m going with around an inch or less of total snowfall in Duluth and Superior on Thursday.


...Arctic Blast…

  • A prolonged period of cold arctic air moves into the Northland starting on Friday, but the brunt of the cold hits Saturday night through Monday, with very cold temps likely persisting most of next week.
  • Daytime highs in the single digits and teens below zero are likely this weekend into early next week in northeast Minnesota and northwest Wisconsin. Overnight lows in the teens, 20s and 30s below are likely this weekend through most of next week, with some -40s possible in the typical cold spots.
  • Dangerously cold wind chills are likely this weekend into much of next week, with wind chill values of around -20 to -45, with -50s even possible on a few nights/mornings. Wind chill advisories and warnings will likely be needed for an extended period starting this weekend.

Everything in weather and its patterns are connected, and this upcoming cold snap is no exception.

Warms up significantly across northern Canada (yellow outlined area on animation below) while arctic air pours S/E (black lines on animation below) out of northwestern Canada and into a large portion of the US starting this weekend. Once this cold air arrives it shows no signs of breaking at least through the end of next week.

12z European ensemble temperature anomaly forecast valid February 5 thru February 12, 2021.

Source: https://weathermodels.com/

A lobe of the Polar Vortex heads S/E into the upper Midwest and Great Lakes this weekend with 500mb height anomalies of around -3 sigma, impressive!

Thickness values could drop to <480 meters across the Northland on Sunday while 500mb heights could go as low as ~5000 decameters as the mid/upper level low passes nearby late this weekend.

12z GFS model 500mb height anomaly forecast valid February 6 thru February 8, 2021.

Source: https://weather.cod.edu/


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