textproduct: Duluth

KEY MESSAGES

- Very warm temperatures (60s and 70s) away from Lake Superior through Friday. Foggy and in the 30s and 40s closest to Lake Superior.

- Dry and gusty conditions are forecast Thursday afternoon leading to near-critical fire weather conditions for areas in Minnesota.

- Rain and thunderstorms forecast on Friday with isolated severe storms possible along I-35 and east into NW WI.

- Colder late Friday and into Saturday, with rain changing to snow possible. Any snow accumulation would be light. The chance for travel impacts is low.

DISCUSSION

Issued at 349 PM CDT Wed Apr 15 2026

Tonight through Thursday night...

Fog is expected to develop once again near Lake Superior and become dense with visibility less than 1/4 mile. A Dense Fog Advisory is in effect from 10 PM tonight until 10 AM Thursday for zones near Lake Superior. Patchy dense fog is possible farther inland and an expansion of the advisory may eventually be needed if conditions warrant.

Inland from Lake Superior will see dry and gusty conditions Thursday with temperatures climbing into the low to middle 70s. Around the shore of Lake Superior temperatures will top out in the 40s and 50s. Clouds may linger over along the Canadian border near International Falls and northwest St. Louis County which would keep temps a bit cooler in the upper 50s to middle 60s. Winds will be from the south at 5 to 15 mph with gusts of 20 to near 30 mph forecast. Efficient mixing will cause RH values to drop below 30 percent for much of the Northland. Near- critical fire weather conditions are forecast for most of our Minnesota area. If fog and low stratus persists longer than expected, the onset of the dry and gusty conditions will be delayed and RH values may not fall as low as currently expected.

Fog and stratus to return again Thursday night. Isentropic ascent ahead of a developing low pressure system over the northern Plains will aid in cloud development over central and north-central Minnesota. Dense Fog Advisories may be needed once again. A chance of light rain, possibly mixed with snow, will nose into northern Minnesota ahead of the system.

Friday through Saturday night...

Low pressure system will progress eastward along with a cool front Friday. Precipitation is forecast to persist or redevelop over Minnesota Friday morning as the system moves east. Over northwest Wisconsin strong Theta-E advection is forecast in the warm sector. Thunderstorms are forecast to develop ahead of the cold front Friday afternoon along and east of the I-35 corridor and over northwest Wisconsin. Favorable low-level hodographs provide support a tornado threat with any storms which can become rooted near the surface. There will also be a risk of large hail with any supercells which develop. The risk is somewhat conditional since the best forcing for ascent may lag behind the greatest instability.

Farther west over central and north-central Minnesota, behind the cold front, precipitation will persist through the day as a mix of rain and snow. Little to no snow accumulation is expected during the day due to the high sun angle and light precipitation rates.

High temperatures Friday will be a sharp contrast with upper 30s near Birchdale in northwest Koochiching County to the low and middle 70s over northwest Wisconsin.

The system will progress farther east Friday night and Saturday. Precipitation will move out of the region Saturday morning. Temps aloft will be cold enough for snow Friday night and early Saturday morning. Minor accumulations of around and inch or less are possible an no travel impacts are anticipated. Saturday will be cool with highs only in the low 30s along the Canadian border to around 40 degrees from central Minnesota through northwest Wisconsin. Scattered rain and snow showers may redevelop in response to diurnal heating Saturday afternoon and taper off Saturday evening.

Sunday through next Wednesday...

Temperatures begin to warm up again on Sunday with much warmer, drier, and gustier conditions Monday. A cold front is forecast to pass over the region Monday night and Tuesday The front is expected to pass by without much precipitation. The timing of the front will play a role in high temps on Tuesday. If the front passes by Monday night and early Tuesday morning, temps will recover into the middle 50s to middle 60s Tuesday afternoon. If the front is slower, temps will be cooler Tuesday. Relatively quiet conditions persist into Wednesday.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 119 PM CDT Wed Apr 15 2026

Skies will continue to clear from southwest to northeast this afternoon. IFR/MVFR ceilings will give way to VFR conditions by around 20Z. Fog and low stratus will develop once again tonight except at BRD. Low ceilings are forecast as well. The low ceilings will be tied to the fog. If fog doesn't develop, skies should remain VFR. Low-level wind shear may develop after 16.21Z as a southerly jet passes over the region.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 349 PM CDT Wed Apr 15 2026

Light northeast winds will persist tonight and strengthen Thursday. Wind and waves may become hazardous to small craft near the Twin Ports. A cold front and area of low pressure will move over the region Friday afternoon and evening. Winds will back northwesterly behind the front and strengthen. Wind and waves will be hazardous to small craft by Friday evening. There is also a risk of thunderstorms over western Lake Superior during the afternoon and evening. A few storms may be strong. Strong wind gusts are possible within a mile or two of shore. Farther away from shore strong wind gusts are unlikely due to the cold water temperatures keeping the lower atmosphere stable. Gusty winds and high waves will persist Saturday and conditions will improve Sunday.

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

FIRE WEATHER

Issued at 238 PM CDT Wed Apr 15 2026

Fog is expected around Lake Superior tonight with otherwise clear skies. RH recovery will be good overnight with maximum RH values above 85%. A low pressure system will move into the northern Plains Thursday. Gusty southerly winds are forecast during the afternoon into the evening. Efficient mixing is forecast once the fog and low stratus burn off. Afternoon RH values will bottom out in the 25 to 35 percent range for areas away from the influence of Lake Superior. Wind gusts of 20 to 28 mph are forecast over central and north-central Minnesota while weaker wind gusts are forecast over the Minnesota Arrowhead and northwest Wisconsin. Near-critial fire weather conditions are anticipated. Warm and gusty conditions are forecast for Friday along the I-35 corridor in Minnesota east across northwest Wisconsin. Scattered showers and thunderstorms are forecast over those areas during the afternoon and evening while a rain/snow mix is favored over central and north-central Minnesota. Precipitation will persist and advance eastward Friday night and Saturday morning as a rain/snow mix. Precipitation amounts will vary from around a tenth of an inch over central and north- central Minnesota to an inch or more where thunderstorms occur in east-central Minnesota and northwest Wisconsin. Colder temperatures are forecast Saturday before the next warming trend begins Sunday. Dry and gusty conditions may return by Monday.

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

HYDROLOGY

Issued at 304 AM CDT Wed Apr 15 2026

Elevated streamflow continues across the Northland, especially along the North and South Shores. Across the Iron Range, Brainerd Lakes, I-35 corridor, and into NW WI (outside of the South Shore), rises have been fairly controlled and minor. On the North Shore, antecedent colder snowpack and a tempered return to warmer spring temperatures has meant the melt is still getting going. North Shore rivers are steadily increasing to what looks like a steady snowmelt level with some diurnal bumps forced by more rapid afternoon melt. The Beaver River near Beaver Bay is within action stage this morning, with water expected to be just coming out of banks at this stage with some possible wet spots along the Superior Hiking Trail. Other North Shore streams are following that lead with high flows expected for most waterways in Lake and Cook County through this week as daily temperatures above freezing keep the melt going.

On the South Shore, rivers have started to turn over and are either holding steady or starting to come down. Flooding continues along the Montreal River on the WI/MI border. An overall downward trend in river stage but with an embedded diurnal bumps is expected as snowmelt is enhanced in the afternoon.

While some passing showers are possible through the week, it's not until Friday-Saturday that a better chance for thunderstorms and widespread rain return to the area. This should allow for remaining snowmelt to keep working through area waterways. By the time Friday rolls around, it seems most plausible that the only significant snowpack remaining would probably be along the North Shore with some pockets of snow lingering in the higher terrain of Bayfield, Ashland, and Iron Counties. Flooding concerns could be two-fold on Friday: rain-on-snow along the North Shore adding onto persisting high flows, and pluvial flash flooding from thunderstorms in areas where conditions are already saturated (mostly NW WI).

DLH WATCHES/WARNINGS/ADVISORIES

MN...Dense Fog Advisory from 10 PM this evening to 10 AM CDT Thursday for MNZ020-021-037. WI...Dense Fog Advisory from 10 PM this evening to 10 AM CDT Thursday for WIZ001>004. MARINE...Dense Fog Advisory until 10 AM CDT Thursday for LSZ140>148-150. Dense Fog Advisory from 10 PM this evening to 10 AM CDT Thursday for LSZ142.