textproduct: Duluth

KEY MESSAGES

- Widespread showers with embedded thunderstorms continue through early tonight. Additional rainfall amounts of 0.5-1" expected for much of the Northland.

- Hazardous marine conditions develop late tonight into Tuesday with gale force wind gusts and high waves across western Lake Superior.

- Additional rain chances late Wednesday/Wednesday night and again Friday into early Saturday. The late week system could bring heavy rainfall (1" or more) to southern portions of the Northland.

- Near-normal high temperatures in the mid 60s to low 70s for the later half of the work week.

DISCUSSION

Issued at 315 PM CDT Mon Sep 14 2026

Rest of Today - Tonight:

An increasingly vertically-stacked low pressure system currently over the Dakotas will slide northeast into southern Manitoba this evening and far northwest Ontario tonight into early Tuesday. An attendant surface occluded front with this system will also move west to east across the Northland this evening and tonight. An area of strong isentropic lift ahead of the front has led to widespread rain showers with a few embedded, non-severe thunderstorms spreading southwest to northeast across the Northland, arriving latest in northwest Wisconsin mid-afternoon. Expect this area of rain to continue through this evening into early tonight, ending from west to east as the occluded front moves through. The isolated, embedded thunderstorm potential persists through early/mid evening (generally ending around 8-10 PM) as elevated instability of 100-400 J/kg MUCAPE will be present. Despite strong bulk shear, this limited instability combined with marginal lapse rates aloft (6 degC/km or less) should keep most thunderstorms that do develop as general in nature. Can't rule out a strong storm or two late this afternoon through early/mid-evening, mainly in northwest Wisconsin, with hail of one-half inch or smaller and heavy downpours leading to ponding of water on roads and low-lying areas as the main threats. Gusty southeast synoptic winds continue to increase through the rest of this afternoon into evening ahead of the front, with gusts up to around 35 mph. We will see a brief lull in winds behind the front later this evening into early tonight before winds increase out of the west again by late tonight/early Tuesday morning.

Regarding precipitation, additional rainfall amounts of 0.5" to around 1" are forecast for the remainder of this afternoon into tonight. Highest amounts remain from central Minnesota into the Iron Range and across far inland northwest Wisconsin. While periodic higher rain rates are possible with any thunderstorms, the more showery nature of these storms should preclude flash flooding, with some patchy ponding on roadways and in low-lying areas being the main concern. This is a welcome rainfall given ongoing drought conditions.

Tuesday - Tuesday Night:

Even stronger winds with gusts of 30 to strong west to northwest winds with gusts up to 30 to 40 mph develop on Tuesday out of the west as the surface pressure gradient remains tight with the low pressure system moving across northwestern Ontario. Wrap around cold air advection and lingering, shallow moisture should keep cloud cover going across much of the Northland Tuesday morning and in far north-central/northern Minnesota through the afternoon and evening. We have also introduced some sprinkle/slight chance (10-20%) rain shower mention in far northern Minnesota on Tuesday, as well. As the low departs farther to the northeast later in the day, winds and gusts will be on a decreasing trend. Slightly below normal high temperatures in the low 60s to around 70F are forecast, warmest in northwest Wisconsin. Light winds, clearing skies, and high pressure settling in on Tuesday night will allow low temperatures to drop into the upper 30s to low 40s, being slightly warmer near Lake Superior and slightly colder into the mid 30s for typical cold spots. Patchy frost is possible in the typical cold spots where temperatures fall into the mid 30s, but widespread frost is unlikely (less than 30% chance of occurrence).

Wednesday - Thursday:

A zonal flow pattern aloft sets up for Wednesday and Thursday. Wednesday will be dry to start, but there is potential for some light rain showers (10-40%) across far northern and southern portions of the Northland Wednesday evening into early Wednesday night as the high pressure departs to the east. An additional surface high pressure center passing to our north Thursday should keep that day dry.

Temperatures moderate slightly for Wednesday and Thursday with high temperatures in the mid 60s to low 70s on Wednesday/Thursday, and some mid 70s in the Brainerd Lakes to northwest Wisconsin on Thursday. Relatively warmer lows in the 40s to low 50s (warmest near Lake Superior) Wednesday and Thursday nights should keep any additional frost chances at bay.

Friday - This Coming Weekend:

Another round of showers and thunderstorms are forecast to return to the Northland on Friday through early Saturday. Lee cyclogenesis develops a surface low in eastern Colorado on Thursday and ejects it through the Central Plains Thursday night/early Friday and into the Upper Mississippi River Valley late Friday into early Saturday. The exact track of the surface low and the northward extent of its attendant warm front and warm sector will dictate precipitation potential, amounts, and locations in the Northland for Friday through early Saturday. The ECMWF EFI QPF values with this system do show a swath of 0.5-0.6 (out of a maximum of 1) into portions of inland northwest Wisconsin along with 90th-plus percentile PWATs relative to NAEFS CFSR climatology, suggesting potential for an unusually higher than normal precipitation signal from several EPS members for this time of year. All this is to say that if the surface warm front sets up in the ideal location just south of the area, a low-level jet riding over to the cool side of the front could set up a band of heavier rainfall in southern portions of the Northland, particularly northwest Wisconsin. The WPC Day 5 Slight Risk area also highlights this potential for heavy rainfall. Additionally, the 13Z 9/14 run of the NBM rainfall amount probabilities for 0.5" or greater are 50-75% south of US-2, highest in inland NW WI, but don't drop off much for 1" or greater with probabilities still 40-65% for the same areas.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 650 PM CDT Mon Sep 14 2026

Complex weather conditions will continue through tonight. I leaned visibility and ceilings on the low end because trends have been so variable, and that is expected to persist through late tonight with showers continuing to pass through (though tapering off around midnight) and lingering low stratus behind the showers until a cold/occluded front passes through and temporarily erodes the low stratus. Onshore winds at DLH may persist another hour or two, but there is low confidence on when exactly winds will switch to southeasterly and then eventually southwesterly later tonight as the front moves through. A fairly abrupt switch from east-northeasterly to southeasterly may happen within 1-3 hours, then another switch towards southwesterly with the front later. LLWS is expected at all terminals at times tonight. Some LLWS at times will persist until midnight, then with the front, a more defined and quick burst of LLWS is expected through around sunrise. Following all this, trending towards some improvement in ceilings, though some wraparound stratus may result in a resurgence of MVFR ceilings through the morning, especially at HIB/INL. Gusty west winds will persist through the day with conditions trending to VFR in the afternoon.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 315 PM CDT Mon Sep 14 2026

Southeast winds increase late this afternoon and evening, with gusts rising into the 20 to 30 knot range this evening, causing waves to rapidly build along the North Shore. Showers with a few thunderstorms are also expected to move across the lake the remainder of this afternoon and evening. No strong or severe storms are expected. After the rain moves across the area, winds veer to southwest then west, strengthening more on Tuesday morning into early afternoon. Gale-force winds of 35 to low-40s kts develop by early Tuesday morning and persist through early afternoon before rapidly decreasing in intensity later Tuesday afternoon and evening. Small Craft Advisories go into effect late this afternoon and persist until Gale Warnings go into effect early Tuesday morning. It is likely there will be a short period of time late Tuesday when Small Craft Advisories will be needed after the Gale Warnings end. Winds and waves will become light Tuesday night and persist at 15 knots or less for Wednesday and Thursday.

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

FIRE WEATHER

Issued at 315 PM CDT Mon Sep 14 2026

Fire weather concerns remain low through the forecast. Widespread showers and some embedded, general thunderstorms bring over half an inch to locally around 1" to the Northland through early tonight, with rain ending from west to east later this evening into tonight. Minimum relative humidity values that got down to 45 percent this afternoon in northwest Wisconsin will continue to increase as rain moves in. Southeast winds with gusts reaching 25 to 35 mph today will shift to the west and gust as high as 30 to around 40 mph on Tuesday behind a departing low pressure system. Lingering cloud cover/moisture on Tuesday should keep min RH above 45%. Winds will diminish for the remainder of the week, with min RH on Wednesday of 40-60% (lowest in northwest Wisconsin) and 45-60% on Thursday. Additional light shower chances are possible in far northern and southern portions of the Northland late Wednesday and better shower (40-80%) and thunderstorm chances on Friday into Saturday.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...Small Craft Advisory until 4 PM CDT Tuesday for LSZ121. Small Craft Advisory until 7 AM CDT Tuesday for LSZ140>148-150. Gale Warning from 7 AM to 4 PM CDT Tuesday for LSZ140>148-150.