textproduct: Duluth

KEY MESSAGES

- Dangerous, critical fire weather conditions continue this afternoon and will be even worse on Friday with Red Flag Warnings in effect due to gusty winds and low relative humidity.

- An anomalous severe weather setup is becoming increasingly likely Sunday and especially Monday, bringing a widespread threat for all severe hazards.

- Heavy, potentially flooding rainfall will accompany this powerful storm system late this weekend into early next week, with flash flooding possible.

DISCUSSION

Issued at 105 PM CDT Thu May 14 2026

For the rest of the day, strong high pressure continues to exit to our east, allowing a tightening pressure gradient to drive increasing southerly winds across the Northland. Frequent wind gusts of 25 to 40 mph, combined with an initially very dry air mass dropping relative humidity values into the 20s, will keep critical fire weather conditions in place. Red Flag Warnings remain in effect. By late this afternoon and evening, a lifting warm front will introduce scattered, high-based showers and isolated thunderstorms. Given the very dry low levels, much of the initial precipitation may struggle to reach the surface, and we may see some dry lightning which also adds to the fire weather concerns.

Tomorrow brings an even more dangerous fire weather environment. As a dry, cold front sweeps through the region, deep boundary layer mixing will tap into very dry air aloft, sending relative humidity plummeting into the upper teens to low 20s. Westerly to southwesterly winds will howl, gusting between 30 and 40 mph across much of northern Minnesota and northwest Wisconsin. Red Flag Warnings and Fire Weather Watches have been issued to highlight this significant threat. By Saturday, high pressure briefly builds back in, offering lighter winds and a slight reprieve, though dry conditions will maintain near-critical fire weather concerns, especially in northwest Wisconsin.

The synoptic pattern shifts dramatically on Sunday as a highly dynamic and potent trough ejects out of the Rockies. Lee cyclogenesis is expected across the Central Plains, with some ensemble members depicting central pressures dropping below 990 mb. This will trigger a massive surge of Gulf moisture northward into our region with PWATS creeping to 1.75", generating a large, highly buoyant warm sector with MUCAPE exceeding 2500 J/kg on Monday. Showers and thunderstorms will overspread the area Sunday afternoon and evening along the warm front, where an anomalous overlap of buoyancy and strong shear will support our first round of severe weather.

Monday is shaping up to be a particularly concerning day for the Northland as the deep low pressure system ejects into the Upper Mississippi Valley. This will drive intense shear, forcing, and low-level kinematics, setting the stage for a widespread threat for all severe hazards. A powerful low-level jet will perfectly cross the mid-level jet, creating an intense shear-buoyancy overlap. Machine learning severe probabilities are exceptionally high for mid-May in the Northland, highlighting up to a 65 percent chance of severe weather for portions of our area and this is corroborated by the SPC's Convective Outlook also highlighting our area for Sunday and Monday.

Alongside the severe weather threat, this system will carry a broad footprint of heavy rainfall Sunday through Tuesday, which would provide welcome moisture for the region. However, the flash flood threat will remain a concern, mainly tied to intense rain rates with the Northland highlighted in WPC Excessive Rainfall Outlook Sunday afternoon through Tuesday morning.

A second trailing low pressure crosses Tuesday adding to the rainfall and potentially giving its own round of severe convection Tuesday morning.

As the system departs by mid-week, wrap-around moisture and cooler air will filter in, returning temperatures to near or slightly below normal levels with lingering, breezy showers.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 105 PM CDT Thu May 14 2026

VFR conditions are expected for the rest of today with gusty southerly winds. An approaching warm front will bring isolated showers this evening. Low-level wind shear (LLWS) will also develop tonight. Gusty southwest winds resume on Friday.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 105 PM CDT Thu May 14 2026

East winds of 10 to 20 knots with gusts to 25 knots this afternoon will become southerly at 15 to 25 knots tonight. On Friday, southwest winds will blow at 15 to 20 knots, gusting up to 30 knots. This will build waves to 3 to 6 feet along the North Shore. Small Craft Advisories remain in effect through Friday evening for Western Lake Superior. Will have to watch out for gales on Sunday and Monday.

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

FIRE WEATHER

Issued at 105 PM CDT Thu May 14 2026

Critical fire weather conditions are occurring this afternoon with southerly winds gusting 25 to 40 mph and relative humidity dropping into the 20s with the potential for dry lightning. Strong high pressure continues to exit to our east, allowing a tightening pressure gradient to drive increasing southerly winds across the Northland. Red Flag Warnings remain in effect. By late this afternoon and evening, a lifting warm front will introduce scattered, high-based showers and isolated thunderstorms. Given the very dry low levels, much of the initial precipitation may struggle to reach the surface, and we may see some dry lightning and evaporationally cooled erratic, gusty winds which also adds to the fire weather concerns.

Tomorrow brings an even more dangerous fire weather environment. As a dry, cold front sweeps through the region, deep boundary layer mixing will tap into very dry air aloft, sending relative humidity plummeting into the upper teens to low 20s. Westerly to southwesterly winds will howl, gusting between 30 and 40 mph across much of northern Minnesota and northwest Wisconsin. Red Flag Warnings and Fire Weather Watches have been issued to highlight this significant threat. By Saturday, high pressure briefly builds back in, offering lighter winds and a slight reprieve, though dry conditions will maintain near-critical fire weather concerns, especially in northwest Wisconsin.

A wet system approaches the forecast area Sunday bringing wetting rains (up to two inches or more which would squash the spring fire weather season) and most likely severe weather.

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 to 9 PM CDT Friday for MNZ010>012- 018>021-025-026-033>038. Red Flag Warning until 4 PM CDT this afternoon for MNZ010-018- 025-026-033>036. Red Flag Warning until 5 PM CDT this afternoon for MNZ011-019- 037-038. WI...Red Flag Warning from noon to 9 PM CDT Friday for WIZ001>004- 006>008. MARINE...Small Craft Advisory from 10 PM this evening to 10 PM CDT Friday for LSZ121-141-142-146>148-150. Small Craft Advisory from 10 PM this evening to 4 AM CDT Saturday for LSZ140. Small Craft Advisory until 10 PM CDT Friday for LSZ143>145.