textproduct: Duluth

KEY MESSAGES

- Lingering heat and humidity today through Friday along with less humid conditions. Heat Advisories may still be needed through the remainder of the week.

- Near-critical fire weather conditions expected today. Smoke is expected to bring poor air quality to most of the region into at least Thursday.

- Better chances for showers and thunderstorms arrive for Thursday into Friday.

DISCUSSION

Issued at 304 PM CDT Tue Jul 14 2026

High pressure was centered over the Mid-Mississippi Valley early this afternoon and extended eastward to the Mid-Atlantic. It also stretched northwestward into the Northern Plains and Canadian Prairies. A cold front extended from northern Quebec southwestward across southern James Bay, northwestern Ontario, and into northern Minnesota and North Dakota. This front will move south this afternoon and into tonight before stalling out across central Minnesota and northern Wisconsin. There isn't a strong push of cooler air behind the front, but winds will turn northwesterly as it passes and help scour out the very high dewpoints that have been in place. Ahead of the front, highs will again be in the 90s with 60s and low 70s dewpoints keeping dangerous heat conditions in place. An Extreme Heat Warning remains in place for almost all of the Northland into this evening. There remains a small chance (30% or less) of an isolated shower or thunderstorm ahead of the front. CAMs were a bit more robust with this activity overnight, but have backed off in more recent runs. However, a line of storms did develop around midday along the front, but quickly fizzled out.

Critical fire weather conditions remain in place across northern areas with dewpoints crashing in the wake of the cold front. This has dropped RH values into the 20 to 30 percent range with northwesterly winds at 5 to 15 mph. A Red Flag Warning remains in effect in this area. With the drier air continuing to push southward behind the front tonight, RH recovery is expected to be poor with values topping out in the 50-60% range north of US 2. Near-critical fire weather conditions will be seen across almost all of the Northland tomorrow with afternoon RH values falling into the 20 to 35% range. Winds will be northerly to northeasterly at 6 to 12 mph.

As winds become northwesterly behind the cold front tonight, wildfire smoke is expected to spread to the southeast over Lake Superior and then turn southwesterly across northwest Wisconsin into the Twin Ports and east-central Minnesota Wednesday. Smoke is expected to be rather thick across northeastern Minnesota and much of northwestern Wisconsin are forecast to reach Maroon (Hazardous to all) to Purple (Very Unhealthy to Everyone) levels. Air Quality Alerts have been issued for all of the Northland through at least Thursday.

The front looks to stall out across central Minnesota with northwest flow persisting aloft. As various shortwaves round the trough axis and move through the region along with upward motion across the stalled front/warm front, there will be low chances for showers and thunderstorms Wednesday into Thursday. Highs Wednesday will range from the middle 80s north to lower 90s south. With not much cooling tonight and highs again in the 90s tomorrow, have extended the Extreme Heat Warning for our southern tier of counties, aside from Price, with a Heat Advisory for the next tier north and Price County. Areas north of there do not have any headlines at this time with highs in the 80s and much less humid. Highs Thursday look similar with perhaps a bit more humid conditions to the south and additional headlines may be needed. A lake breeze is expected to develop Thursday with northeasterly winds across Lake Superior. This will keep areas near Lake Superior in the 70s and lower 80s and bring an increased chance for rip currents to Twin Ports beaches.

A stronger shortwave will propagate through the Upper Midwest late Thursday into Friday and bring an area of low pressure through the region. This will bring better chances for showers and thunderstorms during this time, but questions remain as to where the best rainfall will occur. Some models keep the best rainfall across Canada in addition to timing differences. With this package, the Arrowhead has the best chance of seeing at least 0.50 inches from this system. Beyond that, there are hints of a stronger system for the Sunday into Monday timeframe with an upper low passing to our north. Temperatures will remain above normal through the weekend in the 80s before trending closer to normal heading into next week with highs in the 70s and 80s.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1232 AM CDT Wed Jul 15 2026

Slow moving frontal passage drops southward and shifts already- light winds to northerly to northeasterly today. Smoke will drop southward behind this frontal passage and bring about fairly widespread MVFR to low-end VFR visibility conditions. A few hours of high-end IFR visibility also cannot be ruled out at a few terminals as the more intense smoke bands move through. Right now the sky cover was mostly kept as SKC, but if these more intense smoke bands propagate through Amendments with IFR ceilings may be needed at especially DLH and HYR today. Smoke lasts into Wednesday night onward.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 304 PM CDT Tue Jul 14 2026

Southwesterly winds of 10 to 20 knots will become northwesterly behind a cold front this evening with speeds of 6 to 12 knots overnight. Light and variable winds will prevail across much of western Lake Superior for Wednesday with southwesterly winds of 6 to 12 knots near Grand Portage. Thursday will see winds turn easterly at 5 to 10 knots. Stronger winds of 5 to 15 knots with gusts to 20 to 25 knots will be possible at the head of the lake and may lead to conditions hazardous to small craft. Wildfire smoke will likely lead to reduced visibilities tonight into Thursday with areas of fog remaining possible at times as well.

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

FIRE WEATHER

Issued at 304 PM CDT Tue Jul 14 2026

A cold front has started moving southward across northern Minnesota and is bringing much lower dewpoints in its wake and bringing winds around to the northwest. Minimum RH of 20-25% is expected along with 5 to 10 mph winds gusting up to 15 mph in Koochiching, northern St. Louis, and inland Lake and Cook County where a Red Flag Warning is in effect. Relative humidity recovery will be poor overnight in northeast MN with maximum RH of maybe 55-60% north of Hwy 2 (should be better for the Brainerd Lakes into NW WI). Very dry relative humidity are expected again on Wednesday with afternoon RH of 20-35% across the entire Northland. Northerly winds will be lighter, but near-critical fire weather conditions are possible.

As the cold front works its way south, there is a very small (10-20%) chance that a few showers and thunderstorms could pop up along it late this afternoon and evening. No severe weather is expected if storms do form and rain amounts would be minimal.

With that wind switch, smoke from wildfires in northern Minnesota and Ontario is expected to push into NE MN and NW WI. Models which depict smoke dispersion indicate possible near-surface smoke pushing into the area by this evening and then following the cold front as it pushes south. MPCA and WI DNR have issued Air Quality Alerts covering all of the Northland with Maroon - Hazardous level conditions across the Arrowhead.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Heat Advisory until 9 PM CDT this evening for MNZ025-035-037. Extreme Heat Warning until 9 PM CDT this evening for MNZ033- 034-036-038. WI...Heat Advisory until 9 PM CDT this evening for WIZ001>004-009. Extreme Heat Warning until 9 PM CDT this evening for WIZ006>008. MARINE...None.