textproduct: Duluth

KEY MESSAGES

- A large system continues through today with heavy wet snow expected for northern MN. Freezing rain for NW WI will transition to a wintry mix later this morning and then to snow in the late afternoon.

- Snow squalls are possible with a clipper moving through Sunday into Monday.

DISCUSSION

Issued at 242 AM CDT Sat Apr 4 2026

Current Conditions/Today:

Ongoing winter storm across the region this morning.

NW WI:

Across NW WI we have seen some impressive radar signatures overnight with some intense freezing rain rates and MRMS indicating at a minimum of 0.25" of ice accumulation at 3AM across Burnett and into Sawyer. With the surface low still in southern IA we don't anticipate much fluctuation in the warm nose aloft over NW WI. Freezing rain will remain the primary threat until after sunrise when temperatures warm to above freezing and we switch over to more rain. Rates however look to lessen over the next several hours as a lobe of PVA exits the area. An upper level low deepening over MN will continue pushing east through the late morning hours and by the afternoon will usher in colder temperatures with another precipitation type transition to snow. The latest guidance is suggesting a dry slot will accompany this Low and may slip its way into NW WI. Snow accumulations are not looking overly impressive for the inland portions of the state, but wind direction will be switching to out of the north as the cold air filters in. This will allow for some LES to impact the South Shore before everything tapers off Saturday night. Overall, expect very icy conditions this morning. There was a slight southerly shift in ice placement so we did change the Ice Storm Warning for Douglas to a Winter Storm Warning.

NE MN:

The first dousing of snow that was expected to take shape earlier this evening has not panned out too well. Radar still shows some weak bands of snow traversing up through MN but it seems the best forcing for ascent is displaced both to the west and east. However, if we look upstream to the Northern Plains we can see the upper level low is churning some better snowfall signatures over ND. An upper level jet rounding the base of this low will help to strengthen this low as it moves towards the Upper Midwest. This jet will also end up flowing over the Northland providing a boost to divergence aloft. The better forcing for snowfall looks to arrive after 4AM across our west with projected rates maxing out around 1" per hour. The strongest forcing remains locked over the region until the early afternoon hours. However, with this slight adjustment in timing we have tapered snow totals down a tad. Model soundings don't show a very deep DGZ and the higher sun angle of April should cut down our SLRs. The NBM originally had around 16:1 advertised, but that seems a bit high considering the aforementioned factors. So we opted to pull those down across the board and cap it at a max of 12:1. high temperatures are also expected to be just on the cusp of freezing which will help in the compaction of snow that falls. Activity starts ramping down in the late afternoon with snow exiting overnight. Overall, the lowering of snow totals does not impact the current Winter Storm headlines. Heaviest snow potential remains across our west and along the North Shore.

Sunday:

A clipper drops in from the NW on Sunday leading to yet another dose of winter. Not expecting much for snowfall at this time as high temperatures are expected to climb into the low 40s. Our main concern will be the potential for snow squalls or convectively driven snow showers to develop. Deterministic guidance is showing a rush of cold air advancing across Lake of the Woods and SE in the afternoon and evening hours leading to steep low level lapse rates and increased instability. A few of the high res guidance is also painting a line of showery activity along this boundary. Depending on just how cold the air is on the backside of this boundary we may be looking at a flash freeze set up. Timing still remains a big factor as we will quickly lose our the low level lapse rates after sunset.

Monday:

Quite a bit cooler on Monday with a polar air mass moving across Manitoba. Highs across our north will be sub 30 and NW WI will struggle to get above freezing. Cyclonic flow aloft with some lingering low level moisture may spawn some scattered snow showers in the afternoon. The South Shore will also see some LES with cold NW winds streaming over Lake Superior.

Midweek:

Slight warming trend as we head into the mid week with highs climbing back above freezing on Tuesday. The pattern does turn active again Wednesday as a Low pressure out of British Colombia moves east along the International Border. Ensemble of the Lows keep the majority of the clusters north of the region which will help to pull in warmer air from the south. Highs on Wednesday look to soar into the 40s and 50s. With these warmer temperatures in place this system will bring a mix of rain and snow.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1252 PM CDT Sat Apr 4 2026

Mixed MVFR/IFR conditions are expected to prevail this afternoon and evening, but with some gradual improvement expected as low pressure moves off to the northeast and snow tapers off. Enough dry air may move in later tonight at INL and possibly HIB for a few hours of VFR conditions. Some radiational fog may be possible at INL during the morning if skies clear enough. There will be another shortwave trough approaching from the northwest on Sunday, and a bit more moisture along with cold air moving in will allow for MVFR ceilings to redevelop Sunday morning wherever they might have cleared out. Scattered snow showers are possible at INL at the tail end of the period Sunday. Expect some wind shifts this afternoon and evening as low pressure departs, and then northwesterly winds through the period.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 1021 AM CDT Sat Apr 4 2026

Some headline changes with this update. Winds are below gale force for most areas, so widespread downgrades to Small Craft Advisory have been issued. Gale Warnings will remain from Taconite Harbor to Grand Portage until this afternoon as some stronger gusts will remain possible there. As winds switch northwesterly tonight, expect gusts to around 25 kt to remain until Sunday morning, especially in the Outer Apostle Islands to Saxon Harbor.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Winter Storm Warning until 1 AM CDT Sunday for MNZ011-012-020- 021. Winter Storm Warning until 10 PM CDT this evening for MNZ010- 018. Winter Weather Advisory until 10 PM CDT this evening for MNZ019-037. Winter Weather Advisory until 7 PM CDT this evening for MNZ025- 026-033>036-038. WI...Winter Weather Advisory until 10 PM CDT this evening for WIZ001>004-008. Winter Weather Advisory until 7 PM CDT this evening for WIZ006- 007. MARINE...Gale Warning until 4 PM CDT this afternoon for LSZ140-141. Winter Storm Warning until 1 AM CDT Sunday for LSZ142. Small Craft Advisory until 4 AM CDT Sunday for LSZ142>147. Small Craft Advisory from 4 PM this afternoon to 7 AM CDT Sunday for LSZ148. Small Craft Advisory until 7 AM CDT Sunday for LSZ150.