textproduct: Duluth

KEY MESSAGES

- Light snow and areas of freezing drizzle will create slippery stretches on area roads through late this morning. - Very cold temperatures will lead to dangerous wind chills tonight and early Thursday morning. A Cold Weather Advisory is in effect for portions of northeast Minnesota.

- There are several chances of light snow Thursday through early next week.

DISCUSSION

Issued at 359 AM CST Wed Dec 31 2025

An area of low pressure over western North Dakota as of 3 AM will ride southeastward along a baroclinic zone marked by a cool front at the surface and a temperature gradient aloft toward the lower Missouri River Valley by this evening. To the northeast of the surface low exists a northwest to southeast oriented zone of 925 to 700 mb frontogenesis where winds veer northerly and cold air advection strengthens. Low stratus over the Northland supported patchy freezing drizzle last evening through the early morning. As temperatures aloft cool and forcing for ascent arrives precipitation will transition to light snow and flurries. Regional radar mosaic reveals an area of light snow over northwest Minnesota across eastern North Dakota to southern Manitoba which will propagate southeastward through the morning. Taking into consideration the dusting up to an inch of snow accumulation on top of ice from freezing drizzle, a decision was taken to extend the Winter Weather Advisory at least until 6 AM. It may need to be extended again at that time.

The snow will move out of the Northland late this morning into early afternoon as high pressure builds into the region. Clouds will gradually clear from the northwest to southeast. Lake- effect snow over northern Bayfield, northern Ashland, and northern Iron counties will persist through the day until winds at the surface back more westerly. They may pick up another 1-4 inches of snow today.

The surface high pressure will propagate southeast across the Dakotas and Minnesota tonight. Cold temperatures aloft, weakening winds, and mostly clear skies will allow for efficient radiational cooling. Opted to use the 25th percentile NBM temperatures for lows tonight. That yields minimum temps in the mid to upper 20s below zero along the Canadian border to the low single figures to upper teens below zero from central MN east across northwest Wisconsin. Locations where winds stay a bit stronger will see temperatures stay a bit "warmer" due to continue boundary layer mixing. Wind chills tonight across Koochiching, north and central St. Louis, Lake, and Cook counties will dip to 30 to 40 below zero overnight. We issued a Cold Weather Advisory for those areas. Portions of Cook and Lake counties may warrant an upgrade to an Extreme Cold Warning if temperatures cool faster than forecast and if winds diminish as the high pressure passes nearby. At the moment we expect those areas to see gusty katabatic winds overnight which would prevent temps from falling as drastically as area farther west. If winds do not weaken as forecast elsewhere, temps may end up 5 to 10 degrees warmer than currently forecast.

Another shot of light snow is forecast Thursday due to another transient band of frontogenetic forcing passing over the Dakotas and Minnesota. Low-level stratus will return with that feature. Thermal profiles suggest a deep dendritic growth zone propagating across the Northland. Widespread light snow and flurries can be expected.

A gradual warming trend will begin on Friday as the baroclinic zone over the region wobbles back northward ahead of another weak wave and clipper system moving through the region Friday night and Saturday. There is another chance of snow with that system although amounts should be relatively light, a dusting up to 2 inches.

Warming temperatures continue into next week with several additional chances of light snow. By Monday we will see temperatures on the warmer side of the normal range for early January with highs in the 20s.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1127 AM CST Wed Dec 31 2025

As snow moves out of the area, MVFR and IFR conditions are slowly lifting. Some snow showers linger with horizontal convective rolls throughout northeastern Minnesota, which could lead to some brief declines in conditions through the mid afternoon, as laid out with PROB30s for each TAF. Increased winds this afternoon will slowly decrease overnight. Another shot of light snow will affect mainly BRD late tonight and early Thursday, but could affect HIB, HYR, and DLH as well, though confidence is much lower for them. Chances for snow at HIB and HYR are around 30%, so went with PROB30s for HIB and HYR for now.

MARINE

Issued at 359 AM CST Wed Dec 31 2025

Strong and gusty northwest winds are forecast today and tonight. Sustained winds of 10 to 20 knots with gusts of 25 to 40 knots are expected. The strongest winds will be along the South Shore this morning. By late afternoon into the evening downslope flow off the North Shore high terrain will bring gales from Silver Bay to Grand Portage. A Gale Warning is in effect for those areas from noon today until 10 am Thursday. Elsewhere conditions will be hazardous for smaller vessels. Winds will gradually back westerly Thursday and weaken. Colder air over the region will result in deep mixing over the water through the remainder of the week. Additional Small Craft Advisories will be needed for portions of the nearshore waters.

For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.

DLH WATCHES/WARNINGS/ADVISORIES

MN...Cold Weather Advisory from midnight tonight to 10 AM CST Thursday for MNZ010>012-019>021. Winter Weather Advisory until noon CST today for MNZ033-034- 036-038. WI...Winter Weather Advisory until noon CST today for WIZ001-002- 006>008. MARINE...Small Craft Advisory until 10 AM CST Thursday for LSZ121- 143>148. Small Craft Advisory until noon CST today for LSZ140>142. Gale Warning until 10 AM CST Thursday for LSZ140>142. Cold Weather Advisory from midnight tonight to 10 AM CST Thursday for LSZ142. Small Craft Advisory until 4 AM CST Friday for LSZ150.