textproduct: Duluth

KEY MESSAGES

- A 40-80 percent probability for scattered rains showers and embedded thunderstorms associated with a weak front on Friday, with the highest probabilities in north-central Minnesota/ Brainerd Lakes region where a quarter to half inch of rainfall is expected, elsewhere lesser amounts.

- There is a 5 to 10% chance of a few strong to severe storms Friday afternoon and evening, mainly south of a Walker to Cable to Phillips line.

- Temperatures gradually warming each day, but generally on the cooler side of the normal range with highs in the 60s to 70s and low temperatures in the 40s to near 50 most nights.

UPDATE

Issued at 258 AM CDT Thu Jun 18 2026

Showers persisted early this morning mainly across northern Wisconsin with another area across the Minnesota Arrowhead. This activity is expected to diminish through the morning as low pressure over lower Michigan moves further east and a cold front currently from near International Falls to Fergus Falls moves to the southeast. Wrap around showers and perhaps some embedded thunder will be possible this afternoon into early evening, but activity is expected to be light with best chances across the Arrowhead. Another chance for showers and thunderstorms will be seen Friday afternoon into evening as a shortwave drops out of Canada through the Northern Plains into the Great Lakes embedded within northwest flow aloft. Cool air aloft and moderately favorable mid-level lapse rates will lead to slightly better instability than early forecasts indicated reaching 500-1000 J/kg. Low level moisture looks limited, leading to high based storms and a risk to mix down gusty winds. Small hail will also be be possible given the low freezing level and mid-level lapse rates. A Marginal Risk for a few strong to severe storms is now in place for areas south of a Walker to Cable to Phillips line. No other significant changes with this forecast package beyond Friday.

DISCUSSION

Issued at 1200 PM CDT Wed Jun 17 2026

An almost fall-like weather pattern persists through the next 6-8 days with temps near to below normal and occasional chances for light precipitation amounts, but strong to severe storms are unlikely.

Today into Thursday an unusually strong surface low deepens across the Upper Midwest towards the Lower Great Lakes, deepening to a ~985mb surface low by the time it is over southern Ontario on Thursday morning, which is approaching (but probably not exceeding) sea level pressure records per WPC climatology records/research. At the synoptic scale, this surface low is rotating around a near- stationary upper low over far northern Manitoba with a broad upper level ridge over the Pacific northwest coast resulting in continued northwest flow over the Northland. As the steady rain and occasional embedded thunderstorms end from west to east this evening, partially clearing skies may lead to a few spots with fog overnight tonight. Wrap-around cooler air advects in on Thursday which will lead to spotty light rain showers and perhaps a thunderstorm, but coverage will be sparse and amounts will be light, less than a few hundredths of an inch where it does rain. With some peeks of sun highs will warm up into mid to upper 60s, which is a few degrees below normal for mid June.

On Friday a weak mid-level shortwave trough aloft will approach from the west with a weak warm to occulued-like front at the surface. With decent low level moisture associated with this airmass, a period of scattered rain showers and weak embedded thunderstorms are expected Friday for much of the Northland, with the best broad-scale lift in north-central into east- central Minnesota. Instability will be weak (less than 400 j/kg MUCAPE) but lapse rates should be steep enough to support some embedded thunderstorms, and depending on the timing if discrete storms form they could pose a brief marginal hail/wind threat. Showers and storms will weaken as they track east towards the Twin Ports/MN Arrowhead and northwest Wisconsin on Friday late afternoon/evening. Around 40-50 percent probability for amounts over a quarter inch for north-central MN, perhaps even over a half inch (15-25 percent prob) where thunderstorms develop. Otherwise increasing clouds west to east Friday with highs just a few degrees warmer than Thursday, around 70 for most spots, but clouds clearing out west to east towards sunset.

For Saturday, an area of high pressure over the Dakotas will build east into the Upper Midwest resulting in dry air moving in. To the north, the near-stationary upper low over northern Manitoba finally breaks its grip as a broad longwave upper level ridge builds over the Rockies and east, with the upper low moving south towards northwest Ontario and Lake Superior on Saturday into Sunday. Depending on how south this low digs, there may be a period of scattered rain showers for parts of the MN Arrowhead on Saturday into Saturday night, then broad subsidence as the low tracks east and the upper level ridge helps to reinforce the area of high pressure over the Dakotas into northern Minnesota. Warmer for the weekend with highs in the low 70s, with surface winds turning from northwest on Saturday to northeast on Sunday, causing cooler temps by Lake Superior on Sunday.

The area of high pressure builds east over the rest of the Great Lakes on Monday, with a pattern change aloft as an upper level trough stretching across the High Plains tracks east early next week, with an associated weak surface low in central to southern Saskatachewan and a cold front stretching from the surface low south through much of the northern and central Great Plains. As this cold front approaches from the west late Monday into Tuesday there will be a brief period of southerly flow at low levels resulting in the continued warming trend for highs - low to mid 70s Mon and Tues - with widespread showers and storms Tuesday as the front moves through from west to east. Thermodynamics will be fairly stable given the Pacific origin of the airmass and a very limited window to advect any richer low level moisture to advect in from the south ahead of the front, so thunderstorms are expected to be weak.

Beyond the 7-day forecast, odds are for the near to slightly below normal temps and slightly above normal precipitation to persist per CPC outlooks - a welcome pattern given the current drought situation over parts of the Northland.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1246 AM CDT Thu Jun 18 2026

Showers have become less numerous through the evening and will continue to dissipate through sunrise. Clearing skies will build in from the west and will support fog development early this morning. VFR conditions return by late morning. A few showers may develop this afternoon and could briefly lower ceilings and visibility if the pass over a terminal.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 258 AM CDT Thu Jun 18 2026

Winds will be westerly today at 5 to 15 knots before becoming northwesterly at 6 to 12 knots for tonight. An isolated shower or non-severe thunderstorm will be possible this afternoon into this evening along the North Shore, mainly east of Taconite Harbor. Winds then become southwesterly on Friday at 5 to 15 knots then westerly at 5 to 10 knots Friday night. A few showers and non-severe thunderstorms will be possible again during the afternoon and evening hours in the western arm of the lake. The best chance for any thunderstorms will be near the Twin Ports.

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

FIRE WEATHER

Issued at 258 AM CDT Thu Jun 18 2026

Many locations received a wetting rainfall over the last 24 hours and light rain chances will persist for today and tomorrow. Rain chances today will be very hit or miss with only a few hundredths expected where rain does occur. Better chances for showers and thunderstorms will be seen Friday, especially for north-central Minnesota and the Brainerd Lakes area. Rainfall amounts up to a quarter of an inch area possible in the strongest storms. Dry conditions return for Saturday, but RH values are currently forecast to remain above 35% for most areas. Winds will also be lighter into the weekend at 5 to 15 mph. Temperatures will be in the 60s and lower 70s through SAturday then warming into the 70s for Sunday into next week.

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.