textproduct: Duluth

KEY MESSAGES

- Warm and muggy conditions today with Heat Advisories in effect. Even hotter and more muggy conditions will occur Sunday and Monday with Extreme Heat Watches in effect.

- Isolated to widely scattered rain showers and non severe thunderstorms are possible today in the Arrowhead and this evening into tonight for the other parts of northeast Minnesota and the South Shore.

- Minimal precipitation in the extended forecast. The lack of rain and fairly low relative humidities combined with the very hot temperatures on Sunday through Tuesday could lead to fire weather concerns in far northern Minnesota.

UPDATE

Issued at 235 AM CDT Sat Jul 11 2026

The primary concerns for this early morning forecast remains today beginning the stretch of very warm and muggy conditions, the extreme heat that is expected at least Sunday and Monday, potentially also Tuesday, and the potential for fire weather conditions Sunday through Tuesday.

The Heat Advisory that is in effect late morning to late evening today was expanded in area into the Brainerd Lakes to far northwest Wisconsin this morning as the dewpoints surge during the morning hours today under mostly sunny skies and heat indices approaching the low to mid-90s. These conditions aid in creating a Moderate to locally Major HeatRisk in the Advisory area at the onset of this heat wave.

The Extreme Heat Watch covering the forecast hottest and muggiest time period of this heat wave starting Sunday late evening was extended in time now through Sunday night and covering all Monday daytime. The area was also expanded in coverage for much of the South Shore alongside the current coverage of much of northeast Minnesota. Very little to no relief from the heat is forecast Sunday night and the high likelihood of heat criteria and possible impacts also being Monday caused the extension in time and expansion in area.

The wind gust forecast for Sunday and Monday trended upward with the inclusion of upper-end percentile guidance of daytime gusts for far northern Minnesota in the forecast-to-be well-mixed environment. Southwest winds gusting around 25 mph are entirely possible with relative humidity of 25-30% and daytime high temperatures of the upper-90s to 100 F. Fire weather headlines may be needed in time for these possible near-critical to critical fire weather conditions along and north of the Iron Range. A few afternoon rain showers and an isolated non severe thunderstorm are expected to only bring less than a tenth of an inch of very localized rainfall this afternoon and evening in this general area.

DISCUSSION

Issued at 325 PM CDT Fri Jul 10 2026

Rest of Today - Tonight:

A diurnal cumulus field has developed across much of the Northland away from Lake Superior this afternoon alongside mainly light winds. High temperatures top out in the low to mid 80s this afternoon, with slightly cooler conditions immediately near Lake Superior. Low pressure moving through northwest Ontario today will bring a weak cold front into portions of north-central/far northern Minnesota by this evening. Forcing from this front and aloft should be rather nebulous as 500 mb heights will continue rising aloft. This sets the stage of a low confidence scenario for isolated to very widely scattered shower and thunderstorm development this afternoon into evening due to the weak forcing, and have kept PoPs in the 10-35% range to reflect this. Best potential for any storms to develop would be in the Brainerd Lakes/Iron Range/Boundary Waters areas. If storms develop, a couple of them could become strong with small hail, gusty winds, and a quick downpour in the Brainerd Lakes to Grand Rapids where 20-30 kt of effective shear and better MLCAPE of 500-1500 J/kg develops from late afternoon through early evening. Instability will be less with eastward and northeastward extent, so any storms that develop farther east and northeast are not expected to be strong.

Saturday:

A prominent upper-level ridge axis shifts into the Dakotas on Saturday with surface high pressure centered to our south and east. We see a similar situation to today develop on Saturday regarding isolated to very widely scattered thunderstorm potential mid/late Saturday afternoon and evening as some very weak, embedded forcing for ascent moves through the Northland on the eastern side of the upper-level ridge axis. An even more robust pool of MLCAPE (1000-2500 J/kg) is forecast for much of northeast Minnesota into portions of northwest Wisconsin, but effective shear will be on the weak side at 15-20 kt. Therefore, most storms that develop should be garden-variety pop-up storms, but can't rule out a couple being able to produce brief gusty winds, small hail, and localized downpours in their short lifespans.

The approaching ridge axis and southerly winds pumping in increasing temperatures and humidity will make Saturday feel hot and muggy. Expect high temperatures in the mid-80s to near 90 degrees, hottest in north-central Minnesota, along with dewpoints in the mid to upper 60s. Wet Bulb Globe Temperatures (WBGTs) also rise into the 79-83F range. Given the combination of hotter temperatures/humidity and higher WBGTs, a Heat Advisory has been issued for much of northeast Minnesota inland from Lake Superior where confidence in the overlap of hottest and most humid conditions are expected. Can't rule out expansion of the Heat Advisory into northwest Wisconsin on Saturday, but confidence was not as high there with this forecast update.

Sunday - Tuesday

For Sunday into early next week, deterministic and ensemble model guidance is in very good agreement for the upper-level ridge/high pressure to be over the northern Plains and Upper Midwest, largely keeping precipitation chances north of the International Border and introducing even hotter temperatures and muggy conditions to the Northland. We are looking at high temperatures each of these days in the upper 80s to mid 90s, with some pockets of upper 90s for highs possible in far northern Minnesota on Sunday and Monday. Some of these temperatures could approach or exceed record daily highs and warm lows; see the "Climate" section below for more details. Temperatures should be slightly cooler near Lake Superior each day. Dew points in the mid 60s to low 70s are also forecast for Sunday and Monday, and should drop into the upper 50s to 60s on Tuesday as a weak cold front moves through the region. WBGTs of 80-85F are also forecast each day, peaking in the late mornings through early evenings. Given this dangerous heat, an Extreme Heat Watch was issued for much of northeast Minnesota on Sunday, with additional periods of Heat Advisories and Extreme Heat Watches likely to be needed on Monday and possibly Tuesday. Overnight lows only dip into the mid 60s to low 70s each night in the early portion of next week, so limited recovery and relief from the heat is expected overnight, particularly for those without access to proper cooling or air conditioning.

As of now precipitation with the cold front on Tuesday is forecast to be minimal to zero (10% chance or less for rain) as the better forcing is favored to be north of the International Border. Therefore, several days with this heat and lack of rain, fairly low afternoon relative humidities (35-50% on Sunday and 25-45% on Monday and Tuesday), and breezy southwesterly winds for the Sunday-Tuesday timeframe may lead to fire weather concerns, especially in the Boundary Waters and far northern Minnesota where afternoon relative humidity will be the lowest. We will need to monitor forecast trends for this period closely regarding any need for fire weather headlines.

Mid to Late Next Week:

There is some indication in mid-range deterministic and ensemble guidance for the axis of the ridge to retrograde westward during the Wednesday-Friday timeframe of next week, which would offer a slight reprieve to the hottest and most humid conditions in the Upper Midwest and some low-end precipitation chances (10-40%) should that come to fruition and allow a few weak disturbances to move through our region. However, confidence in the upper- level pattern for the Upper Midwest remains lower for the latter half of next week and any precipitation chances or less hot temperatures will be dependent on whether or not the upper- level ridge axis shifts west of our region in that timeframe.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 614 AM CDT Sat Jul 11 2026

VFR conditions prevail this TAF period under light southwesterly winds under 15 knots. Diurnal afternoon VFR cumulus clouds are forecast today, especially in far northern Minnesota. A few afternoon rain showers are possible in the Arrowhead today. Another round of showers and very low chances (5-15%) of an isolated non-severe thunderstorms cannot be ruled out for the Iron Range to Twin Ports late afternoon to early evening today. Have gone ahead and included a Vicinity Showers mention for the KDLH terminal this evening for this case. Overnight convection cannot be ruled out after 06Z Sunday moving northwest to southeast, first in the MN Borderlands and could then affect the KDLH terminal around daybreak Sunday. Expect increasingly gusty southwest winds Sunday daytime.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 155 AM CDT Sat Jul 11 2026

Light southerly winds under 15 knots keeps minimal concerns for hazardous conditions on the western waters today. Winds further increase though from the southwest Sunday with gusts forecast around 25 knots offshore of Grand Portage. A single zone Small Craft Advisory may be needed in time for Grand Marais to Grand Portage for those gusty southwest winds that are forecast to last Sunday night and Monday.

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

FIRE WEATHER

Issued at 214 AM CDT Sat Jul 11 2026

Hot and muggy weather sets up today and becomes even hotter for Sunday and Monday in most districts. Heat Advisories, for today, and Extreme Heat Watches, for Sunday through Monday, are in effect due to these conditions. Expect slowly increasing southwesterly winds today to greatly pick up in far northern Minnesota by Sunday afternoon. These gusty southwest winds last through Sunday night. The strongest winds of this hot, relatively dry (minRHs 27-37% along and north of the Iron Range) are expected Monday when sustained winds of 10-15 mph are likely and gusts to 25 mph forecast. A weak cool front switches winds to westerly and decreases slowly Tuesday. Fire Weather headlines may be needed in time for Sunday through Tuesday. Widespread rainfall is not likely beyond a few widely scattered rain showers today in the Arrowhead and tonight first in the Borderlands then towards the South Shore by early Sunday morning.

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

CLIMATE

Issued at 206 AM CDT Sat Jul 11 2026

Daily high temperatures and daily record warm low temperatures are forecast over the next few days at select Climate sites in the Northland. The current temperature record and year it was observed are in the first column, with the current forecast temperature in the second column.

Site Identifiers and Names KINL: International Falls area (measured at Int'l Falls Airport) KHIB: Hibbing area (measured at Range Regional Airport) KBRD: Brainerd area (measured at Brainerd Regional Airport) KASX: Ashland area (measured at JFK Memorial Airport)

Record Daily High Temperatures:

July 11: Forecast KINL: 94/1921 92 KHIB: 89/1970 87

July 12: KINL: 96/1921 99 KHIB: 91/1969 94

July 13: KINL: 93/1983 99 KHIB: 92/1983 94

July 14: KASX: 94/1980 94

Record Daily High Minimum Temperatures:

July 12: Forecast KINL: 69/1898 69 KHIB: 67/1942 66 KASX: 67/2018 65

July 13: KINL: 69/2013 71 KBRD: 73/1936 70 KHIB: 67/1997 68 KASX: 73/1954 70

July 14: KINL: 70/1983 71 KBRD: 72/1901 70 KHIB: 69/1995 69

DLH WATCHES/WARNINGS/ADVISORIES

MN...Heat Advisory from 11 AM this morning to 9 PM CDT this evening for MNZ010>012-018-019-025-026-033>038. Extreme Heat Watch from Sunday morning through Monday evening for MNZ010>012-018-019-025-026-035-037. WI...Heat Advisory from 11 AM this morning to 9 PM CDT this evening for WIZ001-002-006-007. Extreme Heat Watch from Sunday morning through Monday evening for WIZ001>003. MARINE...Dense Fog Advisory until 10 AM CDT this morning for LSZ140>143.