textproduct: Duluth

KEY MESSAGES

- Quiet and warm through midday Monday.

- Rain moves in as early as late Monday afternoon with a several-day-long storm system. Rain changes to snow Tuesday night into Wednesday with some accumulating snow possible for several places along with gusty winds at times.

- Cold weather will move in starting Wednesday, and wintertime temperatures are expected for the near future.

DISCUSSION

Issued at 321 PM CST Sat Nov 22 2025

A broad upper level trough is passing through and keeping some low clouds around northeast Minnesota. Elsewhere, skies are mostly sunny. High pressure will pass by to the south tonight, and on Sunday, winds will gradually become southerly into the afternoon. Temperatures are expected to warm up into the 40s for most and even low 50s in east-central Minnesota into parts of northwest Wisconsin. Expect a mix of clouds and sun. The southerly flow will continue on Monday, leading to another mild and quiet day until rain starts arriving from the south potentially during the late afternoon, if not evening from south to north.

The messy storm system that we've been talking about for a few days is still on track to affect the Northland very late in the day Monday through potentially Thursday. There have been some notable changes with the latest model runs, and I will focus on that and associated impacts. First, what remains the same is a two-phased system with a low coming at us from the south and essentially merging with one approaching from the west. Not much has changed there, but what has changed is that models are now suggesting that the dry slot following Tuesday's initial burst of rain, which was anticipated to have a suppressing impact on snow accumulations, may not actually affect our region quite as much as previously anticipated. Instead, there are more model members suggesting that the low moving in from the west will track essentially overhead on Tuesday, and the precipitation associated with it may affect a good portion of the Northland into Tuesday night and Wednesday morning. With cold temperatures associated with this second low, we should see a transition from rain to mainly snow sometime Tuesday evening into Tuesday night. There could potentially be some pretty favorable vertical lift for several hours Tuesday evening ahead of the upper level trough, and several (but definitely not all) ensembles of both GFS and ECMWF suggest a period of moderate to potentially heavy snow somewhere in the region. With that, uncertainty remains very high because ensembles are all over the place with timing and amounts, and seeing rather stark changes in just a few model runs illustrates to me that there are a lot of moving parts to these merging low pressure systems that the models are struggling to fully make sense of. Therefore, we can start to consider the possibility of a snowier solution to this storm Tuesday night into Wednesday morning with a boost in QPF amounts, but I'm not sold on it yet. Expect more forecast changes in the next couple days.

All things considered, there is high confidence that we will see a period of rain on Tuesday with initially warm temperatures. As we go into Tuesday evening and night, confidence becomes low with precipitation amounts (both QPF and resultant snowfall) and figuring out which areas may see several inches of snowfall accumulation associated with the potential several hour period of strong ascent and lingering higher PWATs with the secondary low. Here are the latest thoughts on probabilities for certain snowfall amounts:

>= 1": 40-80%, highest in northern Minnesota and the South Shore. >= 3": 20-50% in east-central Minnesota and northwest Wisconsin away from Lake Superior, and 50-80% in northern Minnesota and the South Shore. >= 6": up to 20-50% in north-central Minnesota towards the Arrowhead. Up to 40-70% in Iron Co, WI. >= 10": Best chance (~40%) in northern Iron Co. 10-20% chance somewhere in northeast Minnesota.

Snow that does fall Tuesday night should be of the heavy/wet variety initially, but may become closer to "fluffy" Wednesday morning. Some blowing snow may be possible with gusty winds getting up toward 30-35 mph.

Lingering light snow is possible through Thursday with light accumulations. The exception will be the usual snowbelt areas along the South Shore as cold -10 to -15C 850-hPa temperatures move in and turn on the lake-effect machine. The bulk of snow accumulations there are likely to be Wednesday into Wednesday night with lingering light snow into Thursday and Thursday night.

The pattern looks to remain active going into next weekend with broad troughing to the west and ridging east. This sets us up in a Colorado low-style storm track with models hinting at the potential for a larger system somewhere in the Midwest. If it happens and the track favors any part of the Northland, the air will be plenty cold for it to be all snow. So, we'll be keeping an eye on that one.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 529 PM CST Sat Nov 22 2025

MVFR ceilings at INL and near KHIB and KDLH are expected to slowly pull off to the east this evening as dry air moves in tonight with high pressure passing by to the south. Once these clouds move off, VFR conditions are expected through the remainder of the TAF period. Winds are expected to gradually diminish overnight. Depending on how light the surface winds get, we may have some LLWS at HYR/DLH/HIB for several hours tonight before ending early morning. However, winds aloft may only get to 30-35knots, which does not quite make it LLWS, but will have to monitor for that potential overnight.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 321 PM CST Sat Nov 22 2025

Marginally favorable conditions for downsloping katabatic winds are looking to develop along the North Shore for a several-hour period tonight. I upgraded the Taconite Harbor to Grand Portage areas to a short-duration Gale Warning tonight as winds may reach and hover around 35 kt for a few hours. Small Craft Advisories are in effect elsewhere through early Sunday morning with gusty west to northwest winds. Winds are expected to lessen Sunday through early Tuesday. Then, a storm system is expected to bring rain and mixed precipitation Monday night and into Wednesday. Breezy conditions will accompany the storm through around Thursday. Small Craft Advisories will likely be needed at times. Gales may be possible (10-25% chances) around Wednesday.

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...Small Craft Advisory until 6 AM CST Sunday for LSZ121-146>148- 150. Small Craft Advisory until 10 PM CST this evening for LSZ140- 141. Gale Warning from 10 PM this evening to 4 AM CST Sunday for LSZ140-141. Small Craft Advisory until 8 AM CST Sunday for LSZ142. Small Craft Advisory until 4 AM CST Sunday for LSZ143>145.