textproduct: Duluth

KEY MESSAGES

- Steady, moderate rain through tonight will keep water levels high in the Arrowhead where a Flood Watch remains in effect.

- A very low-end threat for an isolated strong storm or two exists late this afternoon into early evening in inland northwest Wisconsin.

- Cooler and progressively drier conditions arrive Tuesday through Friday, bringing low afternoon humidity and possibly a return of fire weather concerns.

- Slight warm up this weekend.

DISCUSSION

Issued at 210 PM CDT Mon Apr 27 2026

Rest of Today - Tuesday:

Areas of dense fog continue in the higher terrain of Duluth to Carlton County this afternoon. A Dense Fog Advisory is out until 4 PM but may be cancelled early as the more widespread rain moves in.

Regional radar shows a broad swath of moderate rain moving northward from south-central MN/western WI that will overspread the Northland this afternoon and evening. This area of rainfall is associated with lift and vorticity associated with a surface low pressure center in south-central MN that will be tracking northeast through NW WI this evening and exiting into Ontario by tomorrow morning. Expect rain to end from southwest to northeast late this evening through early Tuesday morning, and some light snow may even mix in for the Arrowhead as precipitation comes to an end, but snow accumulations are not expected.

Given the widespread cloud cover and rainfall all day, there is only a very limited window of time (~5 to 8 PM) where 200-500 J/kg of instability/MUCAPE will track into portions of inland NW WI, mainly Price County and southern Sawyer County and combine with 30-35 kt of 0-6km shear and mid-level lapse rates of 6-6.5 deg C/km to possibly produce a strong storm or two with small hail as the main hazard. Severe weather is not expected. Otherwise, a few embedded, general thunderstorms will be possible in NW WI late this afternoon and evening.

Rainfall amounts will be on the more moderate side due to limited scope of thunderstorm potential. Additional rainfall amounts forecast are 0.75-1.25" for east-central MN into the Arrowhead and much of NW WI, although some onshore flow on the North Shore could produce some localized 1.5" additional rainfall amounts in higher terrain. Additional rainfall in northeast MN diminishes with westward extent from 0.5-0.75" west of the Arrowhead to around 0.25-0.5" in far north-central MN. With soils still saturated and elevated rivers/streamflows in the eastern Rainy River Basin and the North Shore river basins, runoff from this rainfall should keep river/stream levels elevated into the next day or two as it routes through river systems. Eastern Cook County also still has a few inches of snow depth that rain falling onto could add additional water to runoff. Given these conditions, a Flood Watch remains in effect through the end of the more moderate rainfall tonight for Lake and Cook counties as there could also be some minor erosion on rural gravel roads. While this rainfall should also lead to some rises in the Bad River and Tyler Forks basins along the South Shore, additional minor flooding is not anticipated there. Elsewhere, drier antecedent conditions and lower river/stream levels will limit the flooding potential given lighter to moderate rain rates.

Winds shift northwesterly behind the departing low pressure system late this evening into early Tuesday, with gusts cranking as high as 25-35 mph, locally up to 40 mph along the North Shore before gradually weakening towards late Tuesday morning into Tuesday afternoon. Temperatures will be slightly below normal, with highs in the mid 40s to mid 50s, coolest north. Dewpoints will drop significantly behind the departing low, as drier air and clearer skies filter into the region.

Wednesday - This Weekend:

A predominately dry and similarly cool stretch of weather persists with northwest flow aloft for the second half of the work week. High temperatures in the mid 40s to mid 50s continue, with nightly lows around or just below freezing. Surface temperatures warm back into the 60s away from Lake Superior this weekend as the cooler 850 mb temperatures exit the Upper Midwest. Afternoon relative humidity values continue to trend on the drier side for mid week into next weekend, so near-critical fire weather conditions may gradually return as the week progresses. Luckily, winds/gusts will largely be on the lower side in this timeframe.

Early May:

The Climate Prediction Center indicates a fairly good probability for below normal temperatures across the Upper Midwest and Great Lakes region heading into the 6-10 and 8-14 outlook periods. Precipitation signals generally favor below normal precipitation overall for the western Great Lakes as a general northwest flow pattern aloft persists over the region.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1224 AM CDT Tue Apr 28 2026

Low pressure system is departing to the northeast this morning and will continue to move into Ontario through the day. Radar shows light rain echoes are slowly diminishing. We still have widespread MVFR/IFR ceilings but farther west skies are clearing and we can expect to return to VFR conditions later this morning. Gusty northwest winds are still in place to start the forecast period but will gradually weaken through the day with gusts ceasing after sunset.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 210 PM CDT Mon Apr 27 2026

Small Craft Advisories for northeast winds of 25 to 30 kt continue into this evening, with winds then shifting northwesterly tonight into Tuesday with hazardous conditions for small craft continuing. A Gale Warning has been issued from Silver Bay to Grand Portage late tonight until midday Tuesday for northwest wind gusts up to 35 kt. Winds gradually diminish Tuesday afternoon with winds and gusts forecast to be less than 20 kt for the remainder of the work week.

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

FIRE WEATHER

Issued at 210 PM CDT Mon Apr 27 2026

Widespread rain today and tonight will keep fire weather concerns limited through early Tuesday. However, dewpoints/min RH in the wake of the low pressure system for Tuesday through Friday continue to trend drier. Blustery northwest winds on Tuesday will gradually be weakening through the afternoon, but min RH could dip into the 30-40% range given increased daytime mixing. Winds generally become lighter for Wednesday through the second half of the week, but min RH could dip into the 20s to low 30s each afternoon with peak daytime mixing, which could lead to near-critical fire weather conditions depending on how quickly fuels can dry out in the days following the rain.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Flood Watch until 3 AM CDT early this morning for MNZ012-020- 021. WI...None. MARINE...Small Craft Advisory until 1 PM CDT this afternoon for LSZ121- 148. Small Craft Advisory until 4 AM CDT early this morning for LSZ140>142. Gale Warning from 4 AM early this morning to 1 PM CDT this afternoon for LSZ140>142. Flood Watch until 3 AM CDT early this morning for LSZ142. Small Craft Advisory until 1 PM CDT this afternoon for LSZ143>147-150.