textproduct: Duluth

KEY MESSAGES

- Dense fog this morning creates very low visibilities for those traveling.

- Hot conditions are expected Sunday, with Heat Advisories and Extreme Heat Warnings in effect.

- Conditional threats for severe thunderstorms through Monday morning. If thunderstorms develop, isolated to scattered severe storms are likely, capable of producing damaging winds, large hail, and frequent lightning.

- Warm temperatures continue through the coming week, with occasional precipitation chances.

UPDATE

Issued at 138 AM CDT Sun Jul 26 2026

Infrared satellite imagery early this Sunday morning shows the expanding areal coverage of dense for for inland north-central Wisconsin over the last hour. Surface observation stations show visibilities around or less than one quarter mile for eastern Sawyer County and Price County...further supported by webcam imagery in Park Falls. A Dense Fog Advisory was issued and runs through 9 AM for these two counties given these conditions. Scattered dense fog observations are also ongoing in northeast Minnesota presently. High res model guidance indicates these conditions expand in areal coverage over the next few hours....which may necessitate further areal expansion of the land-based Dense Fog Advisory to the I-35 corridor into Leech Lake and northward along the Iron Range.

Other locations immediately along the Lake Superior shorelines could also have a brief period of marine dense fog move onshore, mainly for the tip of the Bayfield Peninsula.

Hazy skies are expected today from western U.S. wildfire smoke aloft moving in from the west-northwest late morning to this afternoon. High-res model guidance limits most of the smoke to aloft, but very limited concentrations could be lightly smelled at the surface today. For this case, Smoke was added into the Weather forecast this afternoon into the Monday daytime time period.

Very hot conditions remain expected today for areas south of the Iron Range and Leech Lake south into the Brainerd Lakes region in northern Minnesota, and across almost all of northwest Wisconsin. Heat Indices of 95 to 105 degrees F are forecast. The Heat Advisories and Extreme Heat Warnings remain in effect today.

The conditional threat of scattered severe thunderstorms occurring late afternoon today through the overnight hours tonight remains the case for the morning forecast today. Even though the wind begins late this afternoon, the most likely time period for any severe weather today would be mostly favored mid-evening to early overnight hours tonight for a large hail threat, then followed later this evening into the overnight hours for a damaging winds threat. Wind gusts in excess of 70 mph would be possible tonight if the predominant storm mode is able to become clustered. The high uncertainty in the cap actually breaking across much of the region keeps the Chance of Precip forecast limited to a 60% chance at this time, even with high resolution model blends favoring higher chances for the overnight hours tonight.

DISCUSSION

Issued at 214 PM CDT Sat Jul 25 2026

Clouds are clearing this afternoon under west to northwesterly flow, with a hot and humid day developing. Temperatures should jump up quickly with sunnier skies, pushing high temperatures into the 80s to near 90F with moist dewpoints. A Heat Advisory remains in effect for portions of the area through this evening.

As an upper level high pushes east overnight, a weak upper level disturbance along its periphery along with a marginal LLJ could force a couple storms out of a well-capped and somewhat dry air mass along the International Border and into the MN Arrowhead. The primary issue here is the actual development of storms, if that can occur, decent MUCAPE and ample bulk shear should allow for storms to grow into a respectable elevated storm severe threat, with damaging winds and large hail as the primary hazards. As the LLJ weans into Sunday morning, any areas of precipitation that do develop should weaken or diminish.

Sunday, a hot and moist airmass should push from the Dakotas into the Northland. Widespread high temperatures in the 90s (near 100F in the Brainerd Lakes region) combined with dew points in the upper 60s to mid 70s will make for an uncomfortable, and at times somewhat oppressive, heat. Heat Advisories and Extreme Heat Warnings are in effect. With that heat and humidity, an impressive reservoir of instability is expected to develop, with models suggesting 3000- 4000+ J/kg of MUCAPE across Minnesota, Wisconsin, and the UP. Along with that, around 50 knots of bulk shear could combine with steep mid level lapse rates to develop clusters of storms from the International Border and southeastward across the aforementioned region. With the heat we're expecting, there will be a cap to overcome, which seems most likely to occur in the late afternoon to evening hours, but the potential for the cap to not break is there, limiting our PoP forecast for now. Storms will likely be pretty quick if they develop, cruising from northwest to southeast with a damaging wind and large hail threat. Our entire area is in a Slight Risk (level 2/5) for Sunday. As additional upper level shortwaves continue to move along the edge of the high pressure, some storms could continue to form and propagate over the MN Arrowhead into NW WI Monday morning, where a Day 3 Marginal risk is in effect.

Monday and through the work week, temperatures temper slightly, but are still largely expected to be around to above normal with afternoon highs in the upper 70s to upper 80s and overnight lows in the 50s and 60s. We remain in a somewhat stagnant pattern stuck between an upper level high over the Southwest to Central Plains and semi-transient upper level lows moving over central to eastern Canada. This should continue to put us in position to see the influence of occasional ridge running disturbances which could bring spotty rain showers and thunderstorms. Some global models are suggesting the potential for a slightly stronger upper level shortwave to bring a more potent system to the area late in the week, but confidence is extremely low in any solutions that far out at this point.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 645 AM CDT Sun Jul 26 2026

Dense fog at a couple terminals is leading to visibilities at a quarter mile or less at HIB, BRD, and HYR. DLH also has some MVFR fog. This fog will dissipate in a few hours as mixing causes it to lift. Showers and storms are expected this afternoon with MVFR/IFR visibilities possible with heavier rain. Hail and strong, erratic winds are possible with storms as well. Fog could redevelop tonight, but confidence is not high enough to include in any TAF except BRD.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 1245 AM CDT Sun Jul 26 2026

Dense fog continues for western Lake Superior along the nearshore this morning with Advisories in effect. Even as the most dense fog drops south of the far North Shore early this morning and sets up along the South Shore, a return back towards the Grand Marais area is possible again later today. The current Advisories may have to be extended in time or re-issued for nearshore waters into Sunday afternoon. After light easterly winds today, expect an uptick in speeds Monday as a notable lake breeze sets up. Onshore northeast flow of 10 to 15 knots gusting to 20 knots is forecast to create waves around 2 feet Monday.

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

FIRE WEATHER

Issued at 1240 AM CDT Sun Jul 26 2026

The main hazard forecast for fire weather these next few days would be strong to isolated severe thunderstorms, most likely this evening into tonight. Gusty and erratic winds, cloud to ground lightning and large hail are the primary threats from any possible strong storms later today. Otherwise, Extreme Heat is forecast today for districts along and south of US Hwy 2 with Warnings in effect for that heat. Heat Advisories are also still in effect through for all other districts too, but just less hot conditions. West to southwest winds today shift to northerly Monday and bring in a more moderate temperature airmass, although lingering heat for the Brainerd Lakes. A lake breeze off Lake Superior will occur Monday.

Smoke from western U.S. wildfires moves over the region even more so today and is forecast to produce hazy skies, but with limited mixing down to the surface.

See the Fire Weather Forecast product for a more thorough breakdown of fire weather conditions.

CLIMATE

Issued at 1235 AM CDT Sun Jul 26 2026

A few daily temperature records are forecast to be within a few degrees of either bring tied or broken in the Northland today.

Record High Temperatures:

July 26: Forecast KDLH: 92/1930 90 KHIB: 91/2015 91

Record Daily Warm Low Temperature:

July 26: Forecast KBRD: 72/189969

DLH WATCHES/WARNINGS/ADVISORIES

MN...Heat Advisory from 11 AM this morning to 9 PM CDT this evening for MNZ010>012-019>021. Extreme Heat Warning from 11 AM this morning to 9 PM CDT this evening for MNZ018-025-026-033>038. WI...Heat Advisory from 11 AM this morning to 9 PM CDT this evening for WIZ004-009. Extreme Heat Warning from 11 AM this morning to 9 PM CDT this evening for WIZ001>003-006>008. Dense Fog Advisory until 9 AM CDT this morning for WIZ003-004- 008-009. MARINE...Dense Fog Advisory until 10 AM CDT this morning for LSZ142-143- 146-147-150. Heat Advisory from 11 AM this morning to 9 PM CDT this evening for LSZ142.