textproduct: Duluth

KEY MESSAGES

- Patchy fog this morning. A fog bank may develop on Lake Superior and move into the North Shore this afternoon

- A light wintry mix is possible (40%) for far northern MN this evening and overnight. There is also a chance (15%) for some light rain to move across NW WI tonight.

-An impactful winter system will move into the Upper Midwest late Tuesday and continue through early Thursday. This system will be bringing an initial wintry mix and then the potential for moderate to heavy, wet snowfall. Travel impacts are likely to occur.

- The active weather pattern continues late this upcoming week with additional chances for snowfall and more seasonal temperatures.

DISCUSSION

Issued at 332 AM CST Sun Feb 15 2026

Current Conditions/Today:

Surface high pressure remains in place this morning with a shallow upper level trough moving in from the west. This trough is introducing some increased cloud cover and while we do see some radar returns the amount of dry air in the lower levels will evaporate any falling hydrometeors. This cloud cover is likely hindering fog development this morning but upstream we can still see some dense fog in the clearing areas of the Red River Valley. Closer to sunrise we may still see some areas of dense fog but widespread impacts look unlikely given the clouds streaming aloft. Any fog that does develop will erode through the latter morning hours.

Southwesterly winds through the day will continue to promote warm air advection and the eastern half of our CWA should see a fair bit of sunshine. Cloud cover will start roaming in from the west in the afternoon. We still opted to bump temperatures above suggested guidance given the trend over the last couple days but cloud cover may temper those temperatures a bit. For now, expect highs in the 40s with isolated pockets in the low 50s. Additionally, there is a fairly consistent signal for fog to develop over Lake Superior later this morning. If this fog bank materializes it will slowly migrate north as southerly winds usher it to the North Shore during the afternoon hours.

Tonight:

A low pressure system moving across central Ontario will have it's trailing cold front slide through northern MN leading to some precipitation chances. A warm nose extends across most of the region and surface temperatures will likely take awhile before dropping to below freezing. Light rain is the most likely outcome until after midnight when the profile cools, but even then it will likely be a rain snow mix. Accumulations will be minimal. This forecast package does introduce some new PoPs for NW WI tonight as well. A few of the CAMs have picked up on a weak surface low moving across southern MN increasing lift and leading to some rain chances as well.

Monday:

Quiet Monday with surface high pressure over the region. High temps are expected to be in the 40s. Would not be totally surprised if we need to bump these temps up a few more degrees. Especially considering the higher sun angle and the low albedo of our forested region.

Mid Week Winter System; Late Tuesday - Thursday

Setup:

A deep upper level trough digging into the West Coast will send a strong upper level jet gutting through the Four Corners spawning a low pressure in the Northern Rockies on Tuesday. This low will then proceed to accelerate and strengthen as it travels across the Northern Plains and towards the Great Lakes. The low then looks to either retrograde over Ontario or make a beeline for the Hudson Bay depending on the model.

High Confidence Portion:

Confidence is high in the system moving in late Tuesday with lingering impacts into early Thursday. The system will also boast some impressive PWATs upwards of 0.75" which is over the max of climatology for this time of year. While certainly an anomaly it seems very plausible given an atmospheric river heading into Baja that the low will be able to siphon off of, plus some added Gulf moisture to boot. Another interesting tidbit with this system is the sheer strength it is projected to have. A few clusters have the low sitting at around 986mb which would be the at the minimum of the CFSR reanalysis climatology for this time of year.

So what does this mean for the Northland and what else do we have high confidence in? Given the plume of moisture and strong forcing associated with this low the worse conditions for heaviest precipitation are lining up to be Tuesday night through Wednesday morning. The strength of the low pressure system will also see strong winds across the region, especially along the North Shore. The latest EFI values continue to trend upwards for northern MN with an area of 0.95 over the North Shore, the area also has a SoT of 2 indicating a higher boom potential for snow amounts. QPF plumes for the North Shore do show some good clustering in excess of 10" based on a 10:1 SLR. Overall, northern MN stands the best chance at seeing some heavy snow with 6" in 48 hrs probabilities of 50-80%.

Uncertainty Portion:

But what are we less certain off? Low track still remains highly contested between the GEFS and EPS. Previously they had stopped feuding and had some good consensus with clustering lows over southern MN by Wednesday morning. Unfortunately there has been some division with latest trends. The GEFS remains firm with its stance but the EPS is opting for a split low system with a low in the Red River Valley and another in Southern MN. Looking at the 850mb temp trends over the past 6 model runs also shows a slow shift towards the north with each run. This all leads to a question of how far will the warm front extend into the Duluth CWA producing more rain then snow? For now, we have stuck with the NBM solution which has the warm front crossing through the inland portions of NW WI. But given the recent trend in the Euro that may be shifting north into the Twin Ports.

Second Half of the System:

With such high uncertainty on the low track the forecast Wednesday and beyond is very muddy. Wednesday should see a lowering in intensity as the low pressure starts to fill. QPF will also decrease and more cold air will work in from the North. The location of a warm nose remains highly contested and could lead to some problematic freezing rain on Wednesday. This system does look to exit late Thursday but there may be another low right on its heels providing us with another dose of winter. Currently we are carrying 30% PoPs for the second system.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1144 AM CST Sun Feb 15 2026

Aside from some dense fog along portions of the North Shore in the lower terrain near Lake Superior, looking at plenty of VFR conditions and mostly sunny skies today. Cloud cover increases out of the west this afternoon into tonight. Low pressure in Manitoba/northern Ontario and a weak low moving into central Minnesota to northwest Wisconsin tonight will bring some light rain this evening, and a brief, light wintry mix to the Arrowhead late this evening and tonight. INL would be the main impact with potential MVFR conditions. Also can't rule out some light rain late this evening/early tonight at HYR but the potential is less than 20 percent. The wake of the precipitation could introduce MVFR to IFR fog/ceilings at INL tonight into early to mid Monday morning, as well. Most sites also have low (20 percent or less) probabilities of seeing patchy fog tonight, but confidence in occurrence is too low to include in most TAFs with this forecast given cloudy skies overnight.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 748 AM CST Sun Feb 15 2026

A fog bank is expanding southwestward into western Lake Superior, with a small area of fog just northeast of the Outer Apostle Islands, as well. There is some question as to how far southwest the expanding fog bank gets before winds switch to southerly today and stop the southward expansion of the fog bank. For now, have issued a Marine Dense Fog Advisory through 10 PM CST for Taconite Harbor to Grand Portage where confidence is highest in seeing dense fog through this evening. Expansions to the advisory may be needed.

Previous Discussion: Light winds and minimal waves through Monday. A fog bank could develop later this morning over the Outer Apostle Islands and northeast into the open waters. If this cloud does develop the southerly winds will push it towards the North Shore in the afternoon hours. Beyond that there is a lot of disagreement with fog going forward, several models suggest it will expand and engulf the rest of the Lake through Monday.

Northeast winds will ramp up Tuesday ahead of an approaching low pressure system. Gales look likely across the Near Shore waters starting Tuesday night with potential for storm force winds along the North Shore.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Dense Fog Advisory until 10 PM CST this evening for MNZ021. WI...None. MARINE...Dense Fog Advisory until 10 PM CST this evening for LSZ140-141.