textproduct: Duluth

KEY MESSAGES

- Scattered showers and thunderstorms gradually move through north-central and northeast Minnesota, exiting the Arrowhead by mid to late this morning. Severe thunderstorms are not expected, although a few strong storms in far north- central and northern Minnesota capable of producing small hail are possible.

- Dry weather returns today through Wednesday for most of the Northland with the exception being 20-40% chances for showers and non-severe thunderstorms from the Brainerd Lakes east to northwest Wisconsin Tuesday evening into Wednesday morning.

- High temperatures will be warm in the upper 70s to mid 80s for today and Tuesday, then drop by a couple degrees on Wednesday.

- Additional chances for rain arrive later in the week with unseasonably warm temperatures returning.

UPDATE

Issued at 243 AM CDT Mon Aug 31 2026

Added a Dense Fog Advisory for Carlton and southern St. Louis Counties, valid through 9 AM this morning, as several observation sensors (DLH ASOS and COQ AWOS) as well as several MnDOT cameras are showing dense fog with visibility of 1/4 mile or less. Visibilities should improve towards 8-9 AM this morning as fog dissipates. There are some signals in models for dense fog to develop along the higher terrain of the North Shore early this morning, but confidence is not high enough at this time to issue a Dense Fog Advisory up that way yet.

UPDATE

Issued at 209 AM CDT Mon Aug 31 2026

Current Overnight through Today:

As of 200 AM CDT, a band of elevated scattered showers and embedded thunderstorms was located across the Minnesota Arrowhead into the Apostle Islands. This area of precipitation is gradually moving northeast through early this morning in association with an area of warm advection north of a surface warm front draped east from the Brainerd Lakes into northwest Wisconsin. No strong or severe storms are expected with this area of convection. Farther west, another area of scattered showers and thunderstorms in northwest Minnesota is located along and ahead of an occluded front. This second area of convection will move across north-central Minnesota during the current overnight and east across the Minnesota Arrowhead through early to mid- morning, gradually weakening as it gets into the Arrowhead. While most storms will be general in nature, a few strong thunderstorms with small hail up to nickel size cannot be completely ruled out through early this morning.

Outside of storms, low clouds and areas of fog--especially near Lake Superior--continue this morning. The occluded front will quickly move west to east across the Northland this morning through early afternoon, leading to rapidly clearing skies in its wake. There will also be a switch to west to northwest winds with gusts to around 15-20 mph today behind the front. High temperatures will also be on the warmer side today ranging from the upper 70s to low 80s in most of the Minnesota-side of the Northland and mid 80s in northwest Wisconsin. Combined with dewpoints in the 60s in northwest Wisconsin during the afternoon, it will feel muggy with heat index values there in the mid 80s to around 90 F. High-resolution models still show some elevated instability of 1500-2500 J/kg of MUCAPE developing this afternoon and evening in northwest Wisconsin, but the timing of the front will be too early in the day to break through a strong capping inversion and drier air in the low to middle levels of the atmosphere. Therefore, we kept the trend of a dry forecast for northwest Wisconsin this afternoon and evening.

Tuesday - Wednesday:

The vertically stacked low pressure currently in southern Saskatchewan will then propagate east through southern Manitoba and northern Ontario today and Tuesday and to Hudson/James Bay on Wednesday, keeping the Northland largely in zonal flow aloft and high pressure at the surface and most of the area dry for this period. The one exception would be some weak shortwave energy moving through the zonal flow across southern portions of the Northland, including the Brainerd Lakes and northwest Wisconsin. This would drive a 20-40% chance for scattered showers and thunderstorms late Tuesday evening into Wednesday morning. Given precipitation would be fighting drier air at onset, precipitation could be a bit delayed into Tuesday night. Precipitation amount probabilities look lackluster, with only a 10-30% for >0.25" and likely to be only a few hundredths for any locations that actually see any rain.

Seasonably warm temperatures in the upper 70s to mid 80s persist on Tuesday, warmest in northwest Wisconsin. These high temperatures dip a couple degrees on Wednesday but remain above normal for early September.

Late this Week - Weekend:

No significant changes from the previous forecast. See the last paragraph of the "DISCUSSION" section below for more details.

DISCUSSION

Issued at 251 PM CDT Sun Aug 30 2026

Mostly cloudy skies are occurring this afternoon across most of the area with isolated light rain showers occurring ahead of an approaching warm front and associated low pressure. Dewpoint temps and PWAT will be increasing this afternoon and evening as the warm front continues to lift north, with dewpoints in the mid 60s to low 70s by this evening. As a lobe of vorticity at 500mb associated with the vertically-stacked low pressure over the Canadian Prairies propagates through the CWA tonight into Monday morning, this will likely (50-75% chance) bring showers and thunderstorms to the area.

Previous forecasts indicated a potential for isolated severe thunderstorms in north-central MN as this warm front lifted north. However, recent hi-res models runs have reduced the severe potential to the point where severe thunderstorms are not anticipated in the Duluth CWA this evening through tonight. While MUCAPE values will likely be increasing to an impressive 2,000 J/kg overnight into early Monday morning, this instability is unlikely to be realized. A substantial low-level cap will increase sfc-based CIN up to 400 J/kg and dry air in the low to mid levels will likely inhibit severe convection. With this being said, a strong thunderstorm capable of producing up to nickel sized hail will still be possible with gusty winds of 50 mph or less being a secondary concern given the capping.

On Monday, an occluded front is anticipated to sweep through the CWA. This will bring a wind shift with the breezy easterly winds today, which have been causing dangerous swimming conditions around the Twin Ports, switching to the west. Despite MUCAPE values remaining elevated through Monday morning into the early afternoon, significant capping and dry air entrainment in the low to mid levels is currently anticipated to keep things dry in the afternoon. CAMs are all in solid agreement for minimal to no precipitation development along the occluded front on Monday, so kept the forecast dry.

As the vertically-stacked low pressure propagates east-northeast towards Hudson Bay on Monday into Wednesday, this will place the CWA in a fairly benign pattern with a mid-level ridge building. The bulk of precipitation associated with a shortwave lifting north from the High Plains on Tuesday night into Wednesday will likely remain just south of the CWA. Southern portions of the WI CWA has an up to 30% chance for scattered showers and thunderstorms, with QPF progged to be on the light side at a few hundredths of an inch. Elsewhere, dry conditions are forecast on Monday through Wednesday with unseasonably warm temps.

Additional chances for showers and thunderstorms arrive Thursday and continue on and off into the weekend as a series of shortwaves potentially propagate through the area. Signals for decent precipitation are not particularly strong, with most global ensemble members for 24 hour QPF showing relatively light amounts under 0.5" late in the week. Temperatures remain on the warm side for the latter half of the week into next weekend, with highs generally in the upper 70s to mid 80s. Certainly a warm start to September!

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1259 AM CDT Mon Aug 31 2026

Largely MVFR to IFR ceilings persist overnight into early Monday morning along with areas of fog and MVFR to brief IFR visibilities with scattered showers and storms at DLH through 07Z and through the current overnight at INL/HIB. DLH and areas near Lake Superior should continue to see LIFR ceilings in low stratus and even IFR to LIFR visibility in fog through early Monday morning. There is some scattering out to VFR at times near the surface warm front by BRD/HYR, so those terminals could see bouncing around between VFR and periodic IFR/MVFR ceilings. An occluded front moving through on Monday will quickly clear skies from west to east Monday morning into early afternoon, bringing veering westerly to west-northwesterly winds of 6-12 kt with gusts to 15-20 kt behind it through early evening before winds become light out of the southwest Monday evening and Monday night.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 1259 AM CDT Mon Aug 31 2026

Northeast winds of 20 to locally 30 kt persist through early this morning, weakening as a warm front moves through. Small Craft Advisories are in effect through early this morning the Twin Ports and North Shore. Scattered showers and thunderstorms ongoing will slowly push northeast through western Lake Superior through early to mid morning, ending last in Grand Portage by late morning. Winds weaken below 10 knots by late this morning into early afternoon and veer southwesterly, with occasional afternoon gusts to 15 kt. Southwest winds increase on Tuesday with gusts of 15 to 25 kt, strongest from Grand Marais to Grand Portage. Additional Small Craft Advisories may be needed for portions of the North Shore and Port Wing to Outer Apostle Islands late Tuesday morning and afternoon.

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

FIRE WEATHER

Issued at 209 AM CDT Mon Aug 31 2026

Scattered showers and thunderstorms associated with a warm and occluded front will continue across north-central MN into the Arrowhead through early this morning, ending east of the tip of the Arrowhead by mid to late morning. Areas that see storms move through could pick up a quick 0.25-1" of rain. A few of the storms moving in from north-central Minnesota as of 2 AM CDT could become strong with small hail and frequent lightning. However, due to the elevated nature of these storms, strong winds are not anticipated. Erratic wind gusts with any storms could approach 20-30 mph, however. As the occluded front moves west to east through the Northland this morning and early afternoon, winds will quickly veer to west to west-northwesterly for today with daytime to early evening gusts of 13-18 mph. The forecast min RH remains moderately drier today, dipping as low as 33-36% the Chippewa NF and Brainerd Lakes area. Moderately dry min RH values of 30-37% shift east into northwest Wisconsin for Tuesday afternoon. Winds on Tuesday gust to 15-20 mph out of the west for the mid-morning through early evening hours. Some light scattered showers and storms (20-40% chance) are possible Tuesday night into Wednesday morning from the Brainerd Lakes east to northwest Wisconsin, but most of those locations look to only see a few hundredths of an inch of precipitation. Otherwise, fire weather concerns remain minimal for the rest of this week into the weekend with min RH remaining above 40% and additional chances for rain arriving Thursday into the weekend.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Dense Fog Advisory until 9 AM CDT this morning for MNZ037. WI...None. MARINE...Small Craft Advisory until 3 AM CDT early this morning for LSZ140>145. Small Craft Advisory until 7 AM CDT this morning for LSZ140>142.