textproduct: Duluth

KEY MESSAGES

- Dangerous, critical fire weather conditions occur today. Any fires that start will spread rapidly due to 40 mph gusts and humidity as low as 15%. Red Flag Warnings are in effect.

- Severe weather pattern is becoming increasingly likely Sunday and especially Monday to support all severe hazards.

- Heavy, potentially flooding, rainfall Sunday afternoon into Tuesday morning may exceed totals of 2 inches in some areas.

DISCUSSION

Issued at 220 AM CDT Fri May 15 2026

Up Front: Dangerous, critical fire weather conditions will occur across the Northland today. Any fires that do start will spread rapidly.

Early this morning, a few isolated high-based showers and stray lightning flashes remain possible across the Iron Range and the Arrowhead, though rainfall will be very minimal. As the sun rises, mixing deepens between 8 AM and 11 AM, tapping into very dry air and high momentum aloft. This will cause relative humidity to plummet into the 15 to 25 percent range while westerly to southwesterly winds increase significantly.

From late morning to the dusk hours today, dangerous and critical fire weather conditions will be ongoing. Winds will be strongest north of the US Highway 2 corridor, where west- southwest gusts reach 40 mph. Further south, from the Brainerd Lakes into northwest Wisconsin, gusts will generally remain around 30 mph. Unseasonably warm temperatures in the upper 70s to low 80s will aid in creating those dangerous fire weather conditions. Additionally, we are monitoring the potential for patchy blowing dust in the far northern Minnesota Borderlands. Dust lofted from the Dakotas and Canadian Prairies could transport into Koochiching and northern St. Louis counties this afternoon, resulting in a hazy appearance and minor visibility reductions for travelers.

Conditions will briefly settle tonight as winds diminish toward sunset. However, moisture recovery will be poor across northwest Wisconsin and the Brainerd Lakes, where humidity may only rise to around 50 percent. This persistent dryness sets the stage for continued near-critical fire weather concerns on Saturday, particularly in northwest Wisconsin into north-central Wisconsin counties. West-northwesterly winds gust around 20 mph under mostly sunny skies. Cooler temperatures in the 60s Saturday will be cooler than those in northwest Wisconsin where 70s are still expected.

The weather story changes dramatically on Sunday as a powerful and dynamic storm system ejects from the Rockies. Deep moisture will surge northward, fueling widespread showers and thunderstorms. Severe weather is becoming increasingly likely Sunday afternoon and evening, primarily for the Brainerd Lakes and east-central Minnesota regions. All hazards, including damaging winds, a few tornadoes and large hail, are on the table. Heavy rainfall will accompany these storms, with a continued threat for localized flooding as the system lingers through Monday.

On Monday, the severe threat shifts slightly eastward, focusing on east-central Minnesota and inland northwest Wisconsin. Wind shear profiles Monday indicate support for significant severe weather as damaging winds and very large hail are possible. Rainfall totals by Tuesday morning could exceed 1.5-2 inches for much of the area. Being on the northern edge of the warm sector for both days, expect a fairly tight gradient in the ingredients available for severe weather for locations along the US Hwy 2 corridor each day (much less likely northward).

A Canadian Prairies low pressure system is likely to phase with the decaying southerly moisture tap Tuesday and will have to be monitored for its own potential of impactful storms and localized heavy rainfall again.

A tightening pressure gradient sets up Sunday to create a period of strong easterly winds off Lake Superior into the South Shore and much of northeast Minnesota. Wind gusts for shoreline locations of the Twin Ports and North Shore are forecast in the 30 to 40 mph range Sunday and again Tuesday. High temperatures Sunday are forecast in the upper-50s to mid-50s for these locations, while further inland south of a line from MN 210 to WI SR 70 temperatures reach the mid-60s to low-70s.

As the system finally departs mid-week, the region will transition to a much cooler and showery regime with temperatures falling back into the 50s to low 60s. Another warm up towards normal is expected though again to end next week.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 535 AM CDT Fri May 15 2026

Strong westerly winds will mix out 13-16Z today and create sustained winds 15 to 25 knots and gusts of 25 to 35 knots at most terminals through about 23Z. Keeping an eye on the possibility of blowing dusting impacts on visibility for far northern Minnesota terminals this afternoon and early evening as dust in ND and NW MN may become lofted and transported towards INL. Have kept it out of the TAF at this point, but definitely something to at least write here about. Light winds and VFR conditions at or less than 10 knots from 23-03Z onward tonight.

The only rain chances is a 20-30% chance of an isolated thunderstorm this evening after 22Z in Price County region of north-central Wisconsin (areas east/south of PBH).

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 225 AM CDT Fri May 15 2026

A Small Craft Advisory remains in effect for all nearshore waters. Southwest winds of 15 to 25 knots with gusts to 30 knots will build waves to 3 to 6 feet, especially along the North Shore. Winds ease Saturday before a potential Gale Warning is required for Sunday and again Tuesday as a powerful low pressure system arrives. Severe weather cannot be ruled out along the South Shore Monday.

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

FIRE WEATHER

Issued at 235 AM CDT Fri May 15 2026

Dangerous, critical fire weather conditions will occur today. A Red Flag Warning is in effect from Noon today to 9 PM this evening for all of northeast Minnesota and nearly all of northwest Wisconsin. Westerly winds will gust 30 to 40 mph while relative humidity drops to 15-25%. Combined with highs in the upper-70s to low-80s, any fires that do start will spread rapidly. Poor overnight relative humidity recovery is expected tonight for the Brainerd Lakes to east-central and across northwest Wisconsin. The exception is Price County where a nose of moisture sets up this evening and lasts into tonight. Conditions remain near-critical Saturday in Wisconsin.

A widespread heavy rainfall event sets up Sunday afternoon through Tuesday morning for all districts. Severe storms with damaging winds are possible for areas south of US Hwy 2 Sunday PM and again Monday PM. Lingering thunderstorm chances will have to be monitored even for Tuesday AM for possible impactful stronger storms too. Easterly winds will be quite gusty for the South Shore and much of northeast Minnesota Sunday and again Tuesday.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Red Flag Warning from noon today to 9 PM CDT this evening for MNZ010>012-018>021-025-026-033>038. WI...Red Flag Warning from noon today to 9 PM CDT this evening for WIZ001>004-006>008. MARINE...Small Craft Advisory until 10 PM CDT this evening for LSZ121- 141>148-150. Small Craft Advisory until 4 AM CDT Saturday for LSZ140.