textproduct: Duluth

KEY MESSAGES

- A round of showers and storms early this morning will bring some locally heavy rain and lightning to the area, though severe weather is unlikely.

- A second round of thunderstorms will develop this afternoon and evening, with a risk of strong to severe storms which may produce large hail and damaging wind gusts.

- Seasonal, dry conditions return for the later part of this week.

UPDATE

Issued at 210 AM CDT Tue Aug 25 2026

Current Conditions and Today: An initial wave of showers and thunderstorms that developed over North Dakota has spread into northwest and west central Minnesota. This early morning activity is expected to gradually weaken as it moves east. It has already moved out of the plume of greatest instability and is currently rooted in an area of steep mid level lapse rates and warm air advection. For now, I expect these storms to bring a brief, heavy downpour and occasional lightning to the area. Cloud cover should limit fog development early this morning, but our more fog prone locations could still see reduced visibilities before sunrise. For today, these lingering morning showers will give way to a decrease in clouds through early afternoon. Then, this afternoon and evening our primary weather concern becomes strong to severe storms as a cold front sweeps across the region. The combination of heat and humidity with dewpoints rising into the low 60s will contribute to a narrow zone of more than 1500 J/kg of surface based, MLCAPE which translates across the Northland this afternoon and evening. The approach of a potent shortwave and a cold front will help generate thunderstorms during peak heating, along with sufficient deep layer shear for supercells together with multicells/clusters. Large hail and damaging winds are expected to be the primary hazards. We have a Slight (2 out of 5 levels) risk of severe storms from SPC. The greatest threat for severe weather will develop along the Interstate 35 corridor and move east into northwest Wisconsin. These storms will quickly exit to the east by late evening, leaving some lingering showers for overnight. Today should be the warmest day of the week, with highs in the 70s along and north of the Iron Range, and low to mid 80s to the south.

Wednesday: Wednesday will be cooler, as the cold front will have moved east of the area overnight. Winds to shift to the northwest and become breezy, with gusts of 20 to 25 mph. Highs will still get into the 70s, but the wind will make it feel cooler. The upper low which will be northeast of the area, will funnel northwest, cyclonic flow across the area, with scattered showers and isolated thunderstorms during the afternoon. Severe weather is not expected.

DISCUSSION

Issued at 135 PM CDT Mon Aug 24 2026

Current Conditions/Tonight:

High pressure has exited the region this morning with southerly surface winds streaming back into the Northland. Satellite shows a swath of cloud cover slowly moving in from the west and engulfing the region. The radar does show some weak echoes across the region but model soundings still show and impressive dry slot through the low levels which is likely preventing any precipitation from hitting the ground.

A low pressure system moving across the Canadian Prairies will lead to an active weather pattern beginning tonight and through Wednesday. Current expectations are for an area of showers and storms to initiate over the Northern Plains late this evening and travel east through the overnight hours. The better ingredients for strong to severe weather remain to our west where SPC has a Marginal risk outlined. As these storms move east the the 12Z suite of guidance suggests that they will outrun both the strongest instability and available bulk shear. Some of the latest CAMs are maintaining a few more vigorous cells into the early morning hours across our west, but largely expect this activity to weaken into showers for Tuesday morning.

Tuesday:

Ongoing showers are expected to be scattered across the region through the morning hours from the previous nights activity. Despite the cloud cover and morning precipitation, we still expect ample recovery of moisture in the afternoon. A warm and moist air mass ahead of a cold front sliding in from the west will lead to the development of more widespread showers and storms. Modest instability with dewpoints in the 60s should lead to MLCAPE in excess of 1500 J/kg. Bulk shear will also be improving through the afternoon as deep layer shear increases due to the upper level low moving along the International Border. Pairing these together should result in an environment capable of producing strong to severe storms. The latest HREF is also depicting a few impressive updraft helicity tracks suggesting some supercell development. Main hazards look to be hail of 1.5" possible with wind gusts of 65 mph. A tornado can't fully be ruled out as well with strong 3CAPE and ample surface vorticity ahead of the frontal boundary. Peak severe weather timing looks to be between 3PM - 10PM. SPC has our region highlighted in a marginal risk (threat level 1 out of 5).

Wednesday:

The cold front will have moved out of the region on Wednesday with northwesterly winds flowing back across the Northland. The upper level low will still be churning overhead as it scuttles towards the Great Lakes. Residual moisture combined with the cyclonic flow aloft will generate some additional showers with isolated rumbles of thunder. No severe weather is expected though with activity tapering off after sunset.

Into the Weekend:

Another stint of quiet and pleasant weather begins Thursday. Northwest flow continues aloft with surface high pressure over Manitoba expanding into the Upper Midwest. Highs will be back into the 70s with a gradual warm up heading into the weekend. We may see another chance at precipitation to start the weekend as impulses aloft break down the ridge in place. Cross barrier flow through the Northern Rockies may develop a low in the Dakotas that tracks across the Midwest. Still plenty of disagreement in timing amongst models, for now we have 20-30% PoPs for the weekend.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 634 AM CDT Tue Aug 25 2026

Showers and thunderstorms are moving through the Arrowhead early this morning ahead of approaching low pressure. Additional shower and thunderstorm development is very likely (60-75% chance) this afternoon and evening as the low pressure center moves into the area and an associated cold front sweeps through. A few storms this afternoon and evening may become strong to severe, capable of producing damaging winds to 70 mph, large hail to ping pong ball size, and the potential for a tornado or two. Following the cold front, MVFR to IFR stratus will be possible tonight into early Wednesday morning. Fog is unlikely early Wednesday as northwest winds continue overnight.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 210 AM CDT Tue Aug 25 2026

Light east to southeast winds of 5 to 10 knots will persist over western Lake Superior this morning and today with waves generally remaining at 1 foot or less. The primary marine hazard today and tonight will be thunderstorms moving across the lake this afternoon and evening as a cold front approaches. A few of these storms could be strong to severe, capable of producing large hail and wind gusts exceeding 34 knots. Behind the front overnight tonight and early Wednesday, winds will shift to the northwest, increasing to 10 to 15 knots with gusts around 20 knots. Showers will also move across the lake during the afternoon, with a few rumbles of thunder possible. This will cause building waves along the South Shore before conditions improve again Thursday.

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

FIRE WEATHER

Issued at 210 AM CDT Tue Aug 25 2026

Thunderstorms which have developed over eastern North Dakota Monday evening are spreading into northern Minnesota overnight. These storms are gradually losing steam as they travel east into our region through the early morning hours, and rainfall amounts will be somewhat scattershot. Today, minimum RH values will generally remain above 45 percent with southerly winds at 5 to 10 mph with gusts up to 20 mph ahead of an approaching cold front. Showers and thunderstorms will likely sweep across the area this afternoon and evening, but again rainfall amounts will be scattered in nature. Wednesday, relative humidity values will again remain above 45 percent, with northwest winds, increasing to 10 to 15 mph with gusts around 20 to 25 mph. Quiet, dry, and less breezy conditions will return for Thursday and Friday under high pressure.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...None.