textproduct: Duluth

KEY MESSAGES

- Heavy rainfall is possible over inland northwest to north- central Wisconsin this morning. Moderate to pockets of heavy rainfall falling on top of previously heavy rainfall persists for the Brainerd Lakes to Pine County region.

- A Flood Watch is in effect through late this morning from the Brainerd Lakes east into northwest Wisconsin ending at Washburn County where the risk of flooding is greatest.

- Minimal precipitation in the extended forecast with potentially impressive heat this weekend into next week.

- The risk of heat-related illness will increase from Saturday into Sunday.

UPDATE

Issued at 245 AM CDT Wed Jul 8 2026

Heavy rainfall is ongoing across the southern Brainerd Lakes to inland northwest Wisconsin region early this morning. Observed rainfall of 1 to 2.5 inches has been observed so far in this area, although highest right around the Hinckley part of western Pine County where discrete strong thunderstorms moved overheard a few hours ago. An additional 0.5 to 1.5 inches still possible into the early morning daylight hours today for this entire area though of the Northland. The Flood Watch was expanded earlier into the Burnett and Washburn Counties as multiple rounds of heavy rainfall could bring minor flooding to these counties into the commute hours today.

As the heaviest rainfall clears east of the forecast area later this morning, persistent rain showers and capped at mid-levels isolated thunderstorms are possible for far eastern Minnesota, the Arrowhead and northwest Wisconsin. A notable instability gradient sits just south of the region with southern Price County on the far northern edge of it. If, a big if, this gradient can shift a bit further northward then a few strong thunderstorms producing small hail and wind gusts to 50 mph are possible for Price County in north-central Wisconsin. But right now the confidence is fairly low for any strong to severe storms is fairly low.

Guidance continues to trend warmer for the late weekend to early week heat. HeatRisk brings in a general 30-70% chance of Major heat impacts (highest in north-central MN and lowest in inland northwest WI and Arrowhead), but there is high confidence for at least areawide Moderate heat impacts Sunday. High temperatures could in the upper-80s to low-90s are forecast. This heat lasts into early next week then.

DISCUSSION

Issued at 254 PM CDT Tue Jul 7 2026

Main stories for this forecast package involve the potential for heavy rain tonight and early Wednesday then the warm-up this weekend into next week which will raise the potential for heat- related illness.

Synopsis...

As of 19Z this afternoon a nearly stationary front stretched from near Watertown, SD to near St. Cloud, MN to near Bayfield, WI. Regional radar mosaic revealed an area of light rain over eastern North Dakota with showers over a portion of northwest Minnesota. A compact MCS was noted over west-central Minnesota while an MCV from early morning convection was centered over far northeast South Dakota within an area of stratiform rain. The latest SPC RAP analysis revealed MLCAPE values of 2000-3000 J/kg over east-central South Dakota into southwest Minnesota with a gradient northward along and just north of the front.

This afternoon through Wednesday morning...

Expect the MCS to propagate eastward along the instability gradient through late afternoon. It will likely strengthen as greater instability builds ahead and to the south of the complex. Meanwhile the trailing MCV will create a localized enhancement in convergence and lift in its wake. The showers over North Dakota and northwest Minnesota are forecast to spread eastward into northern Minnesota by this evening in response to a lobe of 500 mb vorticity over North Dakota this afternoon which will propagate eastward through tonight.

The main focus for heavy rainfall and a small risk of severe storms will be found along and north of the front. This evening, an 850 mb low-level jet is forecast to develop and create enhanced low-level convergence along and north of the front. Instability will become somewhat limited overnight with MUCAPE values of 500-2000 J/kg straddling the front. Thunderstorms are expected to develop in north-central South Dakota this afternoon and propagate eastward with time tonight. Meanwhile additional storms are forecast to develop over central Minnesota into northwest Wisconsin. The strongest moisture advection will be over the Brainerd Lakes by 08.06Z and will propagate farther eastward overnight.

A reservoir of PWAT values of 2 to 2.5 inches is forecast to build over central Minnesota in response to southerly theta-e advection through late evening. Freezing heights will be around 13kft which combined with limited instability and 0-6 km bulk shear of 30-40 knots should produce low-centroid storms and efficient precipitation production. Several CAMs reveal a training patter of storms tonight over central Minnesota which raises the potential for widespread 1-3 inch rainfall amounts. Isolated 2-4 inch amounts are certainly possible. With all these factors in mind along the the recent rainfall over the Northland, we decided to issue a Flood Watch from the Brainerd Lakes east into Pine County. That area is the most likely to see excessive rainfall. Flash flood guidance over the watch area ranges from 1.5 to 2.25 inches in 1 hour and 1.8-2.5 inches in 3 hours. Those precipitation rates are well within reach given this setup.

The severe weather risk is more limited. The modest instability and mid-level winds will limit the potential for large hail and damaging wind gusts. The greater potential for severe storms is to the southwest of my area.

The existence of the MCS/MCV combination has the potential to displace the strongest convergence south of the Northland for tonight, which would shift the area of heavy rain potential out of our area. These trends will need to be monitored through this evening.

Showers and storms will persist overnight and slowly taper off from west to east Wednesday morning. The risk of flash flooding decreases rapidly as storms weaken.

Wednesday afternoon and evening...

The front is expected to loiter over the southern third of Minnesota into central Wisconsin Wednesday. Another round of showers and storms is forecast to our south which may propagate eastward into the Hayward and Phillips areas during the late afternoon and evening hours. Depending on how far east the heavy rain tonight occurs, there may be a chance of flash flooding over those areas. Temperature will generally trend cooler for Wednesday due in part to lingering cloud cover. Northeast winds will allow a weak lake breeze to propagate well inland keeping temps cooler. Look for high temperatures in the low 80s north and south to the low to upper 70s from the Brainerd Lakes into NW WI and shoreline areas of the Arrowhead.

Thursday through early next week...

We will enter a period of quieter weather for the remainder of this week. Widespread rain chances dwindle as zonal flow develops over the northern Plains and Canadian Prairies. Upper- level ridging will build Sunday into early next week which will allow strong southwesterly theta-e advection to bring a return of upper 80s to low 90s temperatures. Dewpoints will increase as well. The risk of heat-related illness will trend higher starting as early as Saturday and persisting through Wednesday at least. Several rounds of heat headlines may be needed.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 618 AM CDT Wed Jul 8 2026

Showers and thunderstorms will steadily depart the area today. The primary site that could still see heavy rain and thunderstorms today is HYR, with some vicinity showers possible through this morning at all other TAF sites. A IFR to MVFR ceiling should also continue to push out of the area through today, with mostly VFR conditions expected. Fog is expected to develop overnight, with IFR to LIFR visibilities possible for most terminals except INL.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 215 AM CDT Wed Jul 8 2026

Light winds and minimal wave activity is likely for the next few days outside of any thunderstorms. Isolated thunderstorms move over the lake this morning and cannot be entirely ruled out along the shorelines either this afternoon. Dense marine fog may form tonight for the Twin Ports to South Shore. Advisories may be needed in time for this possible dense fog tonight.

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

FIRE WEATHER

Issued at 223 AM CDT Wed Jul 8 2026

Heavy rainfall was observed for all districts south of the Iron Range early this morning. The heaviest rainfall moves out of region through inland northwest Wisconsin later this morning. Afternoon isolated thunderstorms today though keep a slight chance of gusty and erratic winds for far eastern Minnesota and across northwest Wisconsin this afternoon.

A notable gradient in observed minimum relative humidity is expected today for northern Minnesota. MinRHs from 30-40% are forecast along and north of the Iron Range and across the Arrowhead and closer to 50-60% along and south of US Hwy 2. Generally dry conditions with MinRHs from 30-45% are forecast Thursday. Winds today through Friday remain light and slowly increase from the southwest Saturday into Sunday. Seasonable temperatures through Friday warm Saturday and become hot and humid Sunday.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Flood Watch until 10 AM CDT this morning for MNZ038. WI...Flood Watch until 10 AM CDT this morning for WIZ006-007. MARINE...None.