textproduct: Duluth

KEY MESSAGES

- Seasonable temperatures today before a warm up through the weekend with increasing humidity. Dangerous heat and humidity is possible Sunday and Monday. Heat Advisories and/or Excessive Heat Warnings will likely be needed.

- Scattered rain showers and thunderstorms are possible today and Saturday. An isolated thunderstorm this afternoon and evening could be strong with brief gusty winds and small hail, most likely in the Brainerd Lakes area.

- Minimal precipitation in the extended forecast.

DISCUSSION

Issued at 303 AM CDT Fri Jul 10 2026

A little patchy dense fog should burn off this morning before another classic July summer day arrives with a little more heat, humidity, and slight chance for showers and storms. We should find ourselves largely under the influence of increasing upper level ridging today, which will gradually start to push our temperatures and dewpoints up. Expected afternoon highs in the low to mid 80s with dewpoints creeping into the 60s. A reservoir of decent instability should build in the Dakotas and move into western and central Minnesota through the day, along with ~30 knots of bulk shear. As a cold front from a weak surface low to our north assisted by some passing 500mb vort maxes pushes into the area, rain shower and thunderstorm development is possible, but not promised. If they do occur, a few spunkier storms are possible, mostly for the Brainerd Lakes to Grand Rapids area where brief gusty winds, a quick downpour, and small hail are possible. Elsewhere, more pop-up garden- variety thunderstorms would be expected.

Saturday, the same upper level pattern continues as a cut-off upper level high marches into the central CONUS, putting us along the edge of that ridge for the first half of the weekend. Model guidance has trended towards the possibility of some ridge-running upper level disturbances continuing over the Northland Saturday, which could bring another round of showers and thunderstorms in the afternoon and evening. Here again we have a decent instability reservoir to work with but shear is lacking. Storms, if they occur, would be pop- up in nature and lacking in structure, so they would probably chaotically follow outflow boundaries or other meso- to micro-scale forcing until their synoptic forcing and instability wane through the evening. With PWATS over 1.5" any storms that develop Saturday would be capable of putting down some good downpours wherever they pop up along with brief gusty winds as the cores of those storms collapse.

Anyone with outdoor plans should keep an eye to the sky today and tomorrow. While most of the day should be precipitation free and showers widely scattered, quick thunderstorm development and intensification are possible which could be hazardous for those without shelter.

Sunday and into next week, models are in very good agreement that a robust upper level high will move into the Northern Plains and Upper Midwest which should drive the heat and humidity up further across the Northland. Saturday will be the beginning of this heat with some possible widespread high temperatures in the upper 80s to near 90F, but confidence is medium in those values, due to the potential afternoon precipitation and clouds which could keep us slightly cooler. Sunday and Monday we are looking at widespread high temperatures in the upper 80s to mid 90s with dewpoints in the upper 60s to low 70s. Some guidance even wants to push some areas along the Canadian Border over 100F. Our forecast Wet Bulb Globe temperatures are in the 80-85 range on both days. A Heat Advisory may be needed Saturday and widespread Heat Advisories and/or Excessive Heat Warnings will likely be needed Sunday and Monday.

Next chance for rain? Sunday and Monday look to be pretty well locked into the high pressure with precipitation chances pushed to the north of us. Global model guidance seems to be in decent agreement for the upper level high to flatten and have to fight an upper level low moving over Hudson Bay Tuesday-Wednesday next week, so perhaps some weak disturbances might be able to bring us some rainfall then. Confidence is low in that kind of solution at this time.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 627 AM CDT Fri Jul 10 2026

Mostly VFR conditions are expected through the TAF period. Areas of showers and thunderstorms are possible through the day, most likely in the afternoon and evening. However confidence is fairly low for now, so have gone with mostly VCSH groups during the most likely time range. Confidence is slightly higher for BRD, so have added an actual SHRA group there in the afternoon. Most precipitation activity should come to an end through the evening. Expect fairly light southerly winds through the TAF period outside of any thunderstorms that can develop.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 303 AM CDT Fri Jul 10 2026

A light onshore lake breeze is expected again today, with some afternoon gusts of 10-15 knots possible for the Twin Ports and Apostle Islands to Chequamegon Bay. While no headlines are expected, small craft users shouldn't be surprised to have a little northeast chop to work with (up to around 1 foot) this afternoon, which should die down quickly into the evening. Widespread marine dense fog is expected this morning, but model guidance is in decent agreement that it should pull back away from the coasts into the open water during the day. It may return once again overnight into Saturday morning. An isolated thunderstorm or two could become strong with brief gusty winds, a quick downpour, small hail, and frequent lightning this evening. Isolated shower and thunderstorm development is possible again Saturday. Winds on Saturday should be fairly light and mostly resemble a lake breeze, with a tendency to turn southerly into the afternoon and evening. This could lead to some stronger southwesterly winds for the Grand Portage to Isle Royale area as the onshore wind direction is synoptically enhanced. Southwesterly winds strengthen Sunday and Monday with some Small Craft Advisories potentially needed, most likely along the North Shore and Outer Apostle Islands.

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

FIRE WEATHER

Issued at 303 AM CDT Fri Jul 10 2026

Light southerly winds expected today with some afternoon gusts of 10- 15mph possible. We should see increasing dewpoints today, which should bring with it some improved humidity (afternoon minimum RH 35- 50%) and a 20-40% chance for some scattered showers and thunderstorms across the Northland, most likely this afternoon and evening. Any accumulations would be fairly light, a couple hundredths to a couple tenths unless right under a thunderstorm in which case very localized areas could see 0.25-0.50". Another round of widely scattered rain showers and thunderstorms is possible Saturday. Temperatures warm through the weekend, but dewpoints in the 60s to low 70s are also expected, so afternoon RH should fairly consistently drop into the 35-45% range, with the chance for some particularly dry spots to reach 30%. Those lowest RHs are most likely along the Canadian border where the hottest temperatures are expected and the least rain has been observed in the last month, which predisposes the area to slightly drier conditions. Some breezier southwest winds are possible Sunday for north-central Minnesota.

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.