textproduct: Duluth

KEY MESSAGES

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

- Rain and thunderstorms 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.

UPDATE

Issued at 304 AM CDT Wed Apr 15 2026

Widespread dense fog continues this morning across much of the Northland. Most guidance is in good agreement that this fog should burn off through the morning, so we have our Dense Fog Advisory expiring at 15z. Another round of fog is possible tonight for Lake Superior, the MN Arrowhead, and NW WI.

Today through Friday, we'll see prolific WAA shoot high temperatures well above normal into the 50s, 60s, and even low to mid 70s tomorrow. This will be for most of the area away from Lake Superior. Over the lake, that warm air mass should help encourage a lake breeze circulation keeping coastline areas much cooler. Have blended in some high-res guidance to adjust coastal temperatures down for today through Friday. Those very close to Lake Superior (within a couple miles) will likely struggle to get out of the high 30s to low 40s and may see more persistent fog.

A low pressure system across the High Plains will track eastward on Friday as a longwave trough amplifies over the central CONUS. That will bring surge of warm and moist air across the Upper Midwest, while drier moves on top of it. This will set the stage for thunderstorms Friday afternoon and evening ahead of an approaching cold front. As of now, the most likely area for strong to isolated severe storms is along I-35 and east where the SPC has introduced a Day 3 Marginal risk. A few storms could be strong to severe owing to the favorable deep layer shear and 600 to 2000 J/kg of MUCAPE. The primary threat will probably be severe hail from elevated storms, but there is a wind threat given the unidirectional shear profile.

See previous discussion for snow concerns through the weekend.

DISCUSSION

Issued at 1259 PM CDT Tue Apr 14 2026

Current Conditions/Today and Tonight:

Early afternoon radar and and satellite imagery showed an area of showers with embedded thunderstorms across the arrowhead of Minnesota. These were located ahead of a compact little shortwave trough that was skirting along the MN/CA border. For the rest of the afternoon and evening, expect dry conditions as this system exits to the east. Meanwhile, wind remain fairly light under the influence of a baggy pressure gradient, and that will set the stage for another night of low clouds and fog.

Wednesday/Thursday:

A couple of days of dry and warm weather are in store for the Northland on Wednesday and Thursday. Wednesday could start out cloudy and foggy, so temperatures depend on how quickly we can clear out. On Thursday, an area of low pressure will organize across the High Plains, and this will bring southerly winds across the region. Current humidity forecast is around 30 to 35 percent, so will have to watch the trends for fire weather concerns. Otherwise expect spring-like weather with highs in the 60s to near 70, except along Lake Superior.

Friday/Monday:

This low pressure system across the High Plains will track eastward on Friday as a longwave trough amplifies over the central CONUS. That will bring surge of warm and moist air across the Upper Midwest, while drier moves on top of it. This will set the stage for thunderstorms Friday afternoon and evening ahead of an approaching cold front. As of now, the most likely area for storms is along I-35 and east. A few storms could be strong to severe owing to the favorable deep layer shear and 1000 to 2000 J/kg of instability. The primary threat will probably be severe hail, but there is a wind threat given the unidirectional shear profile.

In the wake of this front, expect much cooler temperatures as northwest wind ushers a return arctic air. Meanwhile the overall storm system will become better organized, and an area of deformation precipitation will develop Friday night into Saturday. Thermal profiles support a rain-to-snow transition. Any snow accumulation should be less than an inch of slushy wet snow on grassy surfaces. One would expect lesser snow amounts if this falls during the day on Saturday given the April sun angle and warm pavement temperatures. Snow will end Saturday night, but the cool air will last through the weekend with highs in the lower 40s Sunday and lower 50s Monday.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1241 AM CDT Wed Apr 15 2026

Widespread fog will expand through early this morning leading to IFR to LIFR conditions at all terminals. Fog should burn off with conditions returning to VFR through this morning and midday. Another round of fog could be possible tonight, most likely for DLH, HIB, and HYR. Expect mostly light and variable winds through today.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 304 AM CDT Wed Apr 15 2026

Today should be mostly calm out on the lake, with a light northeast breeze this afternoon as a weak lake breeze circulation starts up. Thursday, stronger northeast winds are expected, with some afternoon gusts up to 20knots at the head of the lake. This period will need to be monitored for a possible marginal Small Craft Advisory. Into Friday, northeast winds continue through the morning, and then become northwest through the afternoon. Gusts of 20-25knots are possible Friday and additional Small Craft Advisories may be needed. Areas of dense fog should burn off through this morning, but another round is expected overnight into Thursday. With very warm inland temperatures Thursday, fog could linger across Lake Superior through the day Thursday and into Friday.

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

FIRE WEATHER

Issued at 304 AM CDT Wed Apr 15 2026

Much above normal temperatures enter the Northland today through Friday. Expect highs in the 50s, 60s, and even low 70s (Thursday) away from Lake Superior. A stout lake breeze boundary is likely to set up around Lake Superior each afternoon. Thursday is expected to be a dry one with good low level mixing and high pressure to our north. Minimum RH could drop to 20-30% away from Lake Superior. Some stronger southerly winds are possible for the Brainerd Lakes, north- central MN and across to the I-35 corridor on Thursday as well, with sustained winds 10-15mph and gust of 20-30mph. Combined with high temps in the low 70s away from Lake Superior, Thursday may need to be considered for possible near-critical fire weather. Winds pick up into Friday and temperatures stay warm, but an incoming system should improve moisture. Thunderstorms, some possible severe, are expected Friday afternoon and evening. All hazards are possible in severe storms and some locally heavy rain is possible. On the back side of that system, some light snow may fall into Saturday.

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 until 10 AM CDT this morning for MNZ010>012- 018>021-026-035>038. WI...Dense Fog Advisory until 10 AM CDT this morning for WIZ001>004. MARINE...Dense Fog Advisory until 10 AM CDT this morning for LSZ140>148- 150. Dense Fog Advisory until 10 AM CDT this morning for LSZ142.