textproduct: Duluth

KEY MESSAGES

- Warm, summer-like, temperatures continue today. Highs will be in the 80s with a few values near 90. Slight cool down for Wednesday and Thursday before heat returns Friday.

- A few clusters of thunderstorms are expected this afternoon and evening generally along and south of US-2 in Minnesota and Wisconsin. The isolated to scattered nature of the storms warrants a 10-30 percent chance of rain at this time. A few storms may be strong to severe with hail of penny to half- dollar size (0.75 to 1.25 inch diameter) and wind gusts of 40 to 60 mph.

- Prominent lake breeze Wednesday will provide cooler temperatures near Lake Superior. The Brainerd Lakes should see temps in the middle and upper 80s with upper 60s and 70s closer to Lake Superior.

- Fire weather concerns increase later this week under high pressure and warm temperatures.

DISCUSSION

Issued at 349 AM CDT Tue May 26 2026

Synopsis:

Split upper-level flow will persist through the weekend into early next week. A deep 300 mb trough along the Pacific coast will become a cutoff low by tonight. The northern stream of the subtropical jet will be displaced northward into far northern Canada as a negatively-tilted ridge builds over the Plains and Canadian Prairie Provinces through the weekend. An upper-level trough will dig into eastern Canada and New England. Several jet streaks will rotate through the flow late this week. Several areas of surface high pressure will progress southeastward from far northern Canada through Ontario toward New England. The upper-level ridge will persist into early next week.

Today and tonight:

Rising mid-level heights over the upper Midwest today will provide weak subsidence above a slow-moving and diffuse cold front over the Northland. Ample sunshine and southerly flow south of the front will create very warm temperatures today, likely the warmest temperatures of the week. Highs will climb into the upper 70s along the South Shore to the upper 80s to low 90s farther inland. Temperatures will be cooler along the Canadian border, north of the cold front. Southerly winds will keep the Arrowhead a bit on the cooler side thanks to cool air advection from Lake Superior. These values are near record highs for Brainerd and Hibbing today. International Falls could run at another high temperature record if temps trend warmer than forecast. Near-critical RH values of less than 25% are forecast from near Walker and Longville northeast to Ely and Sea Gull Lake. Winds should be light over those areas around 5 to 10 mph.

Along and south of the cold front light southerly winds will continue Theta-E advection with dewpoints in the upper 50s to low 60s. The combination of heat and moisture will lead to MLCAPE values of 1000-2000 J/kg by late afternoon amidst 0-6 km bulk shear values of 25-30 knots. Mid-level lapse rates of -6.5 to -7 C/km are forecast with a noticeable layer of drier air in the mid-levels. Given the diffuse nature of the cold front, several clusters of thunderstorms are forecast for this afternoon. Uncertainty in the location of the storm develop means PoPs are generally in the 10-30% range as of this morning. Widespread storms are not anticipated.

One potential enhancing factor is the presence of a convectively generated shortwave trough evident in GOES-East Band 8 water vapor imagery over southeast South Dakota, northeast Nebraska, and northwest Iowa. Additional storms developed farther west toward Pierre SD since 08Z. That shortwave trough should propagate northeastward toward central Minnesota and northwest Wisconsin through early afternoon and could counteract the broad subsidence from rising mid-level heights. Should that wave move into central Minnesota and northern Wisconsin, there would be a localized increase in bulk shear which would support better organized storms. If the shortwave arrives too early or propagates easterly instead of northeast, the weak bulk shear combined with moderate instability would support pulse storms capable of penny to half- dollar size (0.75 to 1.25 inch diameter) hail and downburst wind gusts of 40 to 60 mph. Trends will need to be monitored through the day to re-evaluate this threat.

Wednesday:

The surface boundary sags still farther south as Canadian high pressure pushes south toward the Great Lakes. Winds for all of the area will turn east to northeast. A slightly tighter pressure gradient will translate into stronger northeast winds over western Lake Superior, with gusts up to 25 mph. This will generate a prominent lake breeze with temperatures to cool significantly, with 60s and lower 70s near the lake, while areas farther inland remain hot in the 80s, though not as warm as Tuesday. Isolated showers and thunderstorms remain possible on Wednesday afternoon in the general vicinity of the boundary to our south.

Late this week through early next week:

The surface high pressure builds drifts southward over the forecast area beginning Thursday. Ridging aloft should keep the weather dry and mostly sunny. The surface high pressure will slowly weaken Thursday into early Friday as it sags southward. Northeast winds and a prominent, though slightly weaker, lake breeze is forecast Thursday before winds turn southerly for Friday. There are indications we may get some diurnally driven or weak shortwaves to kick off some low chances for showers and storms (10%) Friday or Saturday. The ensembles have us dry for now, but would not be surprised to add some PoPs back in at some point. Friday should trend warmer again. Saturday and Sunday will see another area of surface high pressure drifting south from near Hudson Bay to Ontario. The tightening pressure gradient will support another lake breeze on northeast winds keeping areas near Lake Superior cooler while areas farther inland will experience continue warm temperatures. The dry and warm conditions Friday and Saturday and the absence of widespread rainfall will increase concerns about near-critical fire weather conditions with low RH values possible.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1232 AM CDT Tue May 26 2026

Mostly clear skies are expected early this morning with winds being light and variable. There is a 30% chance for areas of MVFR to IFR fog developing in KDLH, KHIB, and KBRD by sunrise. Once daytime heating begins, expect fog to dissipate and conditions to become VFR. Scattered showers and thunderstorms will potentially be developing in the late afternoon into evening around KBRD and KHYR along a slow moving cold front. Farther north, dry air behind the cold front is expected to inhibit shower and thunderstorm development.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 349 AM CDT Tue May 26 2026

Light winds this morning will gradually strengthen from the east and northeast through the morning. Wind speeds will increase to 5 to 12 knots. A few gusts to 15 to 18 knots are possible. The strongest winds will be found in the southwest arm of Lake Superior. There is a 5-10% chance of isolated storms this afternoon, generally south of a line from Two Harbors to Outer Island to Ontonagon. Occasional cloud-to-water lightning, locally heavy rain which will reduce visibility to less than 1 mile at times, and small hail up to half-inch diameter. Strong high pressure over far northern Canada will sag southward into far northern Ontario Wednesday and Thursday. The pressure gradient will tighten over western Lake Superior and will create stronger northeast winds of 5 to 18 knots. The strongest wind will be in the southwest arm of Lake Superior. Wind gusts will of 15 to 25 knots are forecast. Conditions may become hazardous for smaller vessels near the Twin Ports and east of Madeline Island south to Saxon Harbor. Waves near the Twin Ports and between Oak Point and Saxon Harbor will build to 2 to 4 feet. Northeast winds will persist Thursday and may also produce conditions hazardous to small craft, although the risk is smaller than Wednesday. Saturday will bring another period of stronger northeast winds.

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

FIRE WEATHER

Issued at 349 AM CDT Tue May 26 2026

Dry, near-critical relative humidity values between 20 and 30 percent are forecast this afternoon from near Walker and Longville to Ely and Sea Gull Lake. The low humidity values will be accompanied by east winds of 5 to 10 mph. A nearly stationary front will slowly sag southward from northern Minnesota early this morning to a Walker to Duluth to Ontonagon, MI line by late morning and slightly farther south through the afternoon. South of this boundary winds will be from the south at 5 to 10 mph. Winds turn east to northeast on Wednesday and a prominent lake breeze develops, keeping the lakeside cooler while dry relative humidity values of 25 to 35 percent are forecast further inland. Similar conditions are forecast Thursday before warmer temperatures, lower RH, and southerly winds return Friday.

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

CLIMATE

Issued at 349 AM CDT Tue May 26 2026

Hot, summer-like temperatures today and Friday could produce temperatures nearing daily record highs at several climate sites. Below are the sites where forecast high temperatures are within 3 degrees of their record values.

Record High Temperatures:

Tuesday, May 26: Forecast Record -------- ------ KBRD: 89 ........ 92 in 2018 KHIB: 86 ........ 88 in 1978

Friday, May 29: Forecast Record -------- ------ KHIB: 86 ........ 88 in 1999 and 2006

DLH WATCHES/WARNINGS/ADVISORIES

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