textproduct: Duluth

KEY MESSAGES

- Areas of smoky conditions continue through the weekend, although not as widespread as the previous couple of days.

- Rain and storm chances return tomorrow with the best chances being Sunday night into Monday. Strong to severe storms will be possible.

- Strong northwest winds on Tuesday may lead to more widespread coverage of smoke across the Northland

DISCUSSION

Issued at 150 PM CDT Sat Jul 18 2026

Current Conditions/Today:

Surface high pressure resides along the MN and Dakotas border this afternoon with light wind streaming in from the north. Satellite shows the smokes from the wildfires up north across the Arrowhead and into portions of NW WI, but not nearly as dense as it has been over the last few days. As such the MPCA has made some modifications to the Air Quality Alert with the hazardous areas being confined to the Arrowhead and the Twin Ports, NW WI has also downgraded the severity from hazardous to Unhealthy. Upon looking at the latest smoke plume modeling from the HRRR, the highest concentrations this afternoon are over the Arrowhead and spilling over Bayfield and east. As we head into the evening hours these pollutants mix more with the marine layer and spread back into the Twin Ports. Winds will also be veering with time which will allow the large plume of smoke over the UP and eastern WI to filter back into the Northland.

Sunday:

Some lingering smoke in the morning hours will be possible across NW WI, the Twin Ports and the Arrowhead. Southwest to westerly winds will begin to stream across the region as high pressure scoots to the east. Smoke and air quality conditions will improve through the afternoon.

An upper level ridge will be in place over the region but an embedded shortwave is expected to ride along its edge and could produce some light rain showers (20% chance) across the International Border in the afternoon. The better chances for precipitation look to arrive in the overnight hours via an occluded system traversing across Manitoba and into Ontario. Placement and exact timing of the bands of precipitation remain contested when comparing the available high res guidance. Warm sector precipitation can always get tricky with where the best forcing of ascent will line up. Most of the guidance seems to be keying in on a strong shortwave that ejects out of the Northern Plains ahead of an upper level jet. MUCAPE in excess of 1000 J/kg with an EML will help to grow some elevated storms with damaging winds and large hail being the primary threat Sunday night into Monday morning.

Monday/Tuesday:

Continued shower and storm chances for Monday as the low pressure system in Canada meanders to the southeast. It's associated cold front will also slide through the region leading to a wind shift from out of the southwest to out of the west. Pending placement of the cold front we will see strong to severe storms develop once again. The convective parameter space looks increasingly favorable for Monday with high MLCAPE and strong upper level shear available for supercell growth. Increased low level helicity may also support a tornado threat to go along with the hail and damaging winds. SPC has a marginal risk (1/5) for MN and a slight risk (2/5) for NW WI.

Tuesday should be a dry forecast but an increasing pressure gradient over the region will lead to strong northerly winds. This may lead to another round of widespread Air Quality Alerts as smoke plumes from the wildfires could engulf the region once again.

Midweek

Winds weaken on Wednesday as high pressure moves over the region. Next chances for precipitation arrive on Thursday behind the departure of the high pressure. Not a lot of consistency among the suite of 12Z deterministic guidance but there are signals for a few ridge runners within our northwest flow to spawn some rain. For now we are carrying PoPs of 20-30% through Friday with Friday having more widespread coverage.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1225 PM CDT Sat Jul 18 2026

Surface high pressure will be moving across the region today and through tomorrow leading to winds today out of the north that switch to out of the west tomorrow. Smoke has cleared a little in the wake of yesterdays storms, but can still be seen on satellite across the Arrowhead and into NW WI. Visibility impacts from smoke are expected to return to DLH/HYR later this evening.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 150 PM CDT Sat Jul 18 2026

Light and variable winds across the Lake this afternoon with patchy areas of smoke still present. Tomorrow, winds will turn to out of the southwest around 5-10 knots, smoke may also become more dense, particularly along the North Shore where the HRRR is hinting at greatly reduced visibilities. Wind speeds will further increase Sunday night with a few gusts around 20 kts.

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

FIRE WEATHER

Issued at 150 PM CDT Sat Jul 18 2026

Surface high pressure will be moving across the region this afternoon and through tomorrow leading to a low wind threat. Min RHs are expected to be 35-45% across the region with the driest conditions expected over the Brainerd Lakes region.

Rain chances return late Sunday into Monday. Some isolated showers will be possible across the Arrowhead in the afternoon on Sunday, but the better chances for more widespread rain arrives overnight and into Monday morning. There will be the threat of strong to severe storms with damaging winds and hail as the primary hazards. The current forecast for rain is largely 0.25-0.50" but if a thunderstorm manages to go over an area the totals could be in excess of an inch.

Monday will see continued rain chances with an increase in winds out of the west. Tuesday will see a wind shift to out of the north with wind gusts of 25 mph possible.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...None.