textproduct: Duluth

KEY MESSAGES

- A quick round of light to moderate snow is expected today, with widespread accumulations of one to two inches by this evening. There is a low (10-20%) chance for some freezing drizzle following the snow this afternoon and evening.

- More quick rounds of snow may affect portions of the Northland Wednesday morning and Thursday PM with light accumulations possible.

- Persistent lake effect snow is likely for the South Shore anytime the wind is out of the north-northwest this week. Additional accumulations of a couple tenths to several inches are possible through the week, greatest in the higher terrain of Bayfield, Ashland, and Iron County.

- Colder temperatures continue for much of the week after today. Thursday morning should be one of the coldest this week, with actual temperatures well below zero. A Cold Weather Advisory may be needed.

DISCUSSION

Issued at 401 AM CST Tue Dec 30 2025

The forecast for the week ahead is bringing a real "hey look at that, it's winter again" theme to the Northland with chilly temperatures, on/off chances for snow across the region, and persistent rounds of lake effect on the South Shore. This is driven by a synoptic setup through Saturday that keeps an upper level low over Hudson Bay with ridging over the Rockies, putting us on the cooler and active portion of a northwest to southeast oriented sub- tropical jet stream. Guidance is in very good agreement on the upper level pattern through this whole week, the discrepancies just come from parsing out which moisture impulses will go where.

The first is arriving this morning, with quick clipper system moving into northwest Minnesota at the timing of writing. There should be a first push of snow this morning through midday, favoring the greatest accumulations for areas along and southwest of a line from Int. Falls to the Twin Ports to Hayward. A quick second round on the backside of the weak surface low should fill in the gaps bringing afternoon and early evening snow for the MN Arrowhead and across NW WI. Guidance continues to be in very good agreement that much of the area should see QPF totals of 0.05-0.15", with high snow to liquid ratios making for a fairly light, fluffy snow, and should shake out to 1-2" across the region, maybe slightly enhanced for the South Shore. Snowfall rates of up to a 0.5"/hour could mean a couple hours of reduced visibilities and quick degradation in road conditions. Due to a loss of ice aloft, there could be a little patchy freezing drizzle that follows this morning's snow but the forcing is very weak, so any accumulations would be minor and on elevated or untreated surfaces.

A few more weak impulses look to catch at least portions of the Northland through the rest of the week. The first should be a fairly narrow band into Wednesday morning that has recently trended slightly north, bringing PoPs and a chance for up to a 0.5" of snow for the Brainerd Lakes to the I-35 corridor. Another quick round of snow continues to be picked up by global ensemble guidance for Thursday afternoon and evening on the backside of a departing surface high pressure. There remain variations in exactly where that might track but it would be another chance for a couple tenths to a inch of snow.

An efficient push of colder air is expected through the week, with most days seeing high temperatures in the teens or colder and overnight lows below zero. The coldest night looks to be Wednesday night into Thursday with the classic recipe of high pressure, a Canadian air mass, and mostly clear skies. Actual temperatures should fall into the teens below zero with wind chills in the negative 20s to 30s. Interesting, this will be in between the departing Wednesday system and the incoming high pressure, so some of the area may still be under a tighter pressure gradient leading to semi elevated northwest winds. The strongest of those wind speeds will be along the North Shore, where they could be further enhanced by a katabatic circulation. There is currently a 20-40% chance of wind gusts exceeding 45mph and this time period will need to be watched for not only Cold Weather Advisories but also a possible North Shore Wind Advisory.

850mb temperatures should fall to around -20C following today's clipper through at least midday Thursday. With north to northwesterly winds in that time period, this should allow for the lake effect snow machine to keep chugging for the South Shore, bringing additional light accumulations of a couple tenths to several inches for the usual lake effect snow belts in Douglas, Bayfield, Ashland, and Iron counties. The passing systems on Wednesday and Thursday will have the ability to inject a little more support and moisture into ongoing lake effect, making for transient periods of increased intensity.

Global guidance suggests that this week's synoptic pattern should break down a bit through the weekend and into next week, with some sort of disturbance potentially moving through in the Sunday-Tuesday timeframe, but that's about the furthest we can speculate on that for now.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1134 AM CST Tue Dec 30 2025

Light snow continues across the Northland. Visibilities are expected to be up and down as showers become more scattered, so opted for TEMPOs for most of the sites. BRD has been reporting some FZRA/FZDZ, but have not seen any impacts at the surface, so have left it out of the TAF for now. MVFR and occasional IFR ceilings are expected for the TAF period for all sites. BRD may see more snow showers Wednesday, so have included a PROB30 to account for that for now. Winds increase out of the northwest tonight and will be up to 20 kts by morning.

MARINE

Issued at 401 AM CST Tue Dec 30 2025

We'll see a brief reprieve from strong winds through most of today before the northwesterlies start up again into Wednesday morning, strongest along the North Shore as usual. Widespread gusts of 20+ knots are likely, with a 50-70% chance of gale force gusts on the North Shore Wednesday evening. A Gale Watch is in effect for Taconite Harbor to Grand Portage beginning Wednesday afternoon through Thursday morning. Elsewhere, small craft advisories will likely be needed. An area of snow moves across Western Lake Superior today, and then lake effect snow will likely continue through mid to late week along the South Shore, which may lead to areas of reduced visibilities.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...Gale Watch from Wednesday afternoon through Thursday morning for LSZ140-141.