textproduct: Duluth

KEY MESSAGES

- Showers exit this afternoon with skies varying between overcast and mostly sunny for the remainder of today.

- An active pattern arrives Sunday night and continues into Monday with several rounds of showers and thunderstorms likely. A few storms on Sunday night into Monday morning may become strong to severe from the Brainerd Lakes to I-35 corridor.

- Depending on the time of arrival of an occluded front on Monday, additional severe thunderstorms may occur over northwest Wisconsin on Monday afternoon. Uncertainty on this second round of severe storms is high at this time.

- A more benign pattern settles over the area around mid-week before additional chances for rain arrive later in the week.

DISCUSSION

Issued at 254 PM CDT Sat Aug 29 2026

A weak amplitude shortwave has been propagating through today, with scattered showers associated with isentropic ascent moving downstream of the CWA this afternoon. In the wake of this precip, skies have been varying between overcast in the southern half of the CWA to mostly sunny near the International Border. Conditions stay on the quieter side this afternoon into tonight as a 500mb ridge briefly slides over the area. This ridge will be fairly messy though with multiple vorticity maxima propagating through tonight into early tomorrow morning, which could develop an isolated shower. Despite these shots of vorticity coming through, keeping the potential low at a 20-25% chance due to a significant cap expected to develop around 800mb as southerly winds bring WAA to the area.

This WAA advection will usher in warmer temperatures on Sunday for the southern edge of the CWA, with highs increasing to the low 80s and dewpoint temps becoming sticky in the mid to upper 60 degree range. The aforementioned capping inversion will likely inhibit convective initiation through the daytime hours on Sunday with skies varying between partly to mostly cloudy.

A warm front associated with vertically-stacked low pressure over the Canadian Prairies is anticipated to lift north on Sunday night, bringing scattered showers and thunderstorms that will continue until Monday morning. A sizable amount of instability will be associated with the warm front, with MUCAPE from CAMs indicating potential values in the 1500-2000 J/kg range on Sunday night around the Brained Lakes towards the I-35 corridor. This will also be accompanied by favorable 0-6km bulk shear up to 40 knots. However, it's worth noting that this is a large divergence from global models, which put timing of peak instability and shear later into Monday. This increases uncertainty with this warm fropa. If timing of peak instability happens more overnight, large hail to ping pong ball size is the primary hazard with damaging winds being unlikely due to the low-level cap. SPC has the southwestern corner of the CWA in a Marginal Risk on Sunday night.

On Monday, the severe thunderstorm potential shifts into northwest Wisconsin as the occluded front associated with the sfc low moves through. Again, impacts on Monday will largely be dependent on timing of this occluded fropa. If the earlier timing becomes favored, most of the convection will likely be exiting by early Monday afternoon and severe storms will be limited to elevated hailers.

If the later timing favored in global models, such as the GFS, occurs then this front will be sweeping through northwest Wisconsin during peak diurnal heating and allow for 1500-2000 J/kg of MLCAPE to develop. With 0-6km bulk shear remaining around 40-45 knots, this could lead to supercell development. If supercells develop, all hazards are possible including damaging winds to 70 mph, large hail up to golf ball size, and locally heavy rain with PWAT to 1.6". A tornado or two also can't be ruled out as hodographs indicate a moderately favorable 60-100 m2/s2 of SRH available to right-moving supercells. This is highly uncertain at this time though given the discrepancies in timing between the various models.

Following the occluded frontal passage on Monday, a more benign pattern settles over the region for mid-week with slightly cooler high temps. Low pressure, following a typical Colorado Low type track, will bring a chance for additional showers and thunderstorms on Wednesday. Additional precipitation will be possible later in the week as the 500mb pattern remains active.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1249 PM CDT Sat Aug 29 2026

Rain showers currently located across northwest Wisconsin continue to exit to the east. In the wake of this precip, MVFR to IFR cigs have been occurring. Lingering IFR conditions early this afternoon are likely to improve to MVFR, with broken MVFR cigs continuing through the afternoon. Tonight, patchy fog is expected to develop with cigs favored to lower to IFR and even LIFR. Confidence in fog is highest for locations that saw rainfall earlier today. Expect this fog to begin improving after sunrise tomorrow as easterly winds begin to increase.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 254 PM CDT Sat Aug 29 2026

The main concern is strengthening northeast winds to upwards of 25- 30 kt on Sunday into Monday morning as low pressure moves into the area. Small Craft Advisories remain in effect, starting on Sunday morning and tapering off on Sunday night into early Monday morning. Thunderstorms will be possible Sunday night into Monday as an occluded front moves east across the area. Some of these storms could be strong with small hail and gusty winds. Outside of thunderstorm winds, winds on Monday remain around 10 kt or less before turning southwest on Tuesday with gusts of 15-25 kt developing.

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

FIRE WEATHER

Issued at 254 PM CDT Sat Aug 29 2026

In terms of min RH, there are minimal fire weather concerns through the forecast period as min RH remains above 40%. Winds will be a slightly different story, especially on Sunday as low pressure and associated surface fronts move through the area. This low pressure is likely to bring scattered showers and thunderstorms to the area, with a few strong to severe storms possible on Sunday night into Monday capable of producing gusty and erratic winds, large hail, and frequent lightning. Easterly winds on Sunday will be breezy late Sunday into Sunday night, gusting 15-25 mph. Expect these winds to shift to the west on Monday morning into the early afternoon as an occluded front sweeps through.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...Small Craft Advisory from 1 PM to 9 PM CDT Sunday for LSZ121- 148. Small Craft Advisory from 10 AM Sunday to 7 AM CDT Monday for LSZ140>142. Small Craft Advisory from 10 AM Sunday to 4 AM CDT Monday for LSZ143>145. Small Craft Advisory from 1 PM Sunday to 1 AM CDT Monday for LSZ146-147-150.