textproduct: Duluth

KEY MESSAGES

- A fast moving Clipper will bring two rounds of wintry mix to the Northland this morning and again this evening into tonight. Travel impacts could result from light snow and ice accumulations in the Arrowhead this morning and near the South Shore this evening into tonight.

- Sunday could see another round of light snow in the Arrowhead, but uncertainty is high. Conditions are currently favored to be dry, but this could change if recent model trends persist.

- An active pattern persists this upcoming week as a couple Clippers move through the Northland. Temperatures are expected to follow a trend of above-freezing temps during the day and sub-freezing temps at night in most locations for much of this upcoming week.

DISCUSSION

Issued at 153 AM CDT Sat Mar 21 2026

Low pressure, currently located in western ND, will be quickly propagating through the Northland today. Precipitation occurring along a warm front associated with this passing Clipper is forecast to bring a wintry mix to the Arrowhead this morning, with the southern gradient of precip being around US-2. Despite radar reflectivity increasing in the Borderlands early this morning, surface observations still report dry conditions at the sfc. Hi-res model soundings reveal a notable dry layer in the low-levels, which is inhibiting this precipitation aloft from reaching the surface. However, the expectation is that once the low-levels saturate later this morning, a wintry mix will begin.

Precipitation type this morning into the early afternoon is expected to be fairly messy across the Arrowhead. Models strongly suggest a warm nose above freezing expanding across nearly the entire CWA by the time saturation through the profile is expected to occur. At the surface, temps are forecast to be around, if not slightly below, freezing along the North Shore above Two Harbors, in Cook County, and portions of interior Lake County. This thermodynamic set-up is conducive for freezing rain development and ice accumulations. There is high confidence (75% chance) for at least a glaze of ice occurring by late morning, and a 25% chance for ice amounts of 0.1".

It's worth noting that the thermal profile this morning is very close to freezing and even a degree or two of variation in the warmer direction could result in this largely falling as rain. Opted against issuing a Winter Weather Advisory for this morning freezing rain, as temps are expected to warm above freezing by this afternoon and quickly melt any ice accumulations. In addition to ice concerns this morning, wet accumulating snow of 3" or less is expected this morning in Cook County. Highest snow amounts will be around Grand Portage, where the coldest temps will be found this morning.

As the low pressure center moves through the CWA around midday into the afternoon, there will be a lull in wintry precipitation. This lull will be brief though as a cold front sweeps through late this afternoon into the evening. This will bring an additional round of wintry mix with light snow amounts under 0.5" along/north of US-2 in northwest WI and a potential glaze of ice in Iron and southern Ashland counties. Expect precip along this cold front to exit the CWA by early Sunday morning.

On Sunday, there is some uncertainty in regards to precipitation in the afternoon and evening. While high pressure is generally favored to develop on Sunday, there are indications that a subtle shortwave moving through on Sunday evening could bring light snowfall. Run-to- run variation hasn't been consistent in this signal, so kept the dry PoPs from the NBM in the forecast update this morning. However, if model trends hold, then this would be one potential change that would be needed.

Heading into this upcoming week, an active pattern is expected to remain over the Upper Midwest as a series of Clippers move through. A few notable time periods that could be seeing precipitation from these Clippers is Monday evening into Tuesday morning and again on Wednesday morning into Thursday. Temperatures are currently progged to maintain a diurnal trend of warming above freezing during the day and then decreasing below freezing overnight for most locations this upcoming week. This will result in messy p-types and place importance on timing for whether or not a location will see more rain versus snow.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 623 AM CDT Sat Mar 21 2026

A clipper system is moving across the region this morning bringing some light precipitation. At the terminals we will see some light rain at times with this morning wave and potential for another round of light rain later this evening. Winds will see an abrupt change in direction this afternoon changing from out of the south to out of the north.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 153 AM CDT Sat Mar 21 2026

Quiet conditions on western Lake Superior this morning will persist through the daytime hours today ahead of an approaching Clipper. However, east to northeast winds will be increase this evening and remain elevated through at least Sunday morning, with gusts of 20 to 25 knots across most nearshore zones and waves building in excess of 4 feet after midnight Saturday along the South Shore. The outer Apostle Islands and the waters off Saxon Harbor could see waves building up to 8 feet. Small Craft Advisories will likely be needed for the North Shore and around and east of the Bayfield Peninsula starting tonight.

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...None.