textproduct: Duluth

KEY MESSAGES

- An area of light rain from southwest Minnesota into northwest Ontario will slowly move eastward and dissipate through this evening.

- A dry conditions Friday with temperatures near to slightly above normal in the middle 60s to low 70s.

- Periodic shower chances return Saturday, followed by a more organized system bringing widespread rain chances early next week.

DISCUSSION

Issued at 250 PM CDT Thu Sep 24 2026

LATE AFTERNOON AND TONIGHT:

A broad area of isentropic lift stretched from southwest to northeast Minnesota early this afternoon along and ahead of a shortwave trough which stretched from far northwest Ontario into southern Minnesota. A lobe of 500 mb vorticity was positioned ahead of the mid-level trough axis. Isentropic moisture convergence was maximized over portions of central and northeast Minnesota, co-located with the returns on the regional radar mosaic. Precipitation intensities were a little lighter than indicated on radar due to bright band effects from a melt layer between 9.5 and 12 kft AGL. This effect is most noticeable at and beyond 80 statute miles (70 nautical miles) from KDLH.

Forcing for ascent will persist through this evening although the mid-level forcing will push ahead of the low-level ascent which will allow the light rain to taper off to drizzle. High- res guidance points to isolated to scattered showers developing late this afternoon and persisting into the evening to the west of the area of light rain. That would include much of central and north-central Minnesota. Precipitation gradually tapers off tonight as the shortwave trough departs. Fog may develop tonight, particularly for areas where rain fell today. The fog may be locally dense in spots. Overnight lows will be in the upper 40s to low 50s.

FRIDAY:

Blocking low pressure will take shape over the New England coast. That feature will shunt the shortwave trough toward the north as it departs. Partly to mostly cloudy skies are forecast for Friday as ridging aloft builds over the northern Plains and Canadian Prairies. Isentropic lift will persist over central and north-central Minnesota which will keep skies mostly cloudy. Farther east clouds will gradually clear during the day. Temperatures will be near normal where clouds linger to 10-15 degrees above normal where sunshine is more abundant. Highs will be in the middle 60s to low 70s. Light winds Friday night should allow areas of fog to develop. Fog may be locally dense in some spots.

SATURDAY:

Another shortwave trough will move into the region for Saturday. Rain chances increase gradually over our Minnesota zones. High pressure to our east will once again make the eastward progression of precipitation difficult as dry air will undercut the precipitation aloft. The greatest rain chances are late Saturday afternoon through early Saturday evening west of a line from Aitkin to International Falls. Rain chances will persist through the night as the trough pushes eastward. Rain amounts will be light, up to around a tenth of an inch over our western areas to a trace farther east. Clouds and showers will limit temperatures for central and north-central Minnesota on Saturday with highs in those areas in the low to middle 60s. Farther east expect upper 60s to low 70s.

The aforementioned blocking low will remain in place over the New England coast with a Rex Block expected to develop over the eastern CONUS and eastern Canada.

Northeast winds are forecast over the southwest arm of Lake Superior which will increase the risk of rip currents for the beaches of the Twin Ports Saturday afternoon and evening.

SUNDAY THROUGH NEXT WEEK:

The Rex Block remains in place to our east for the first half of next week. This will keep an upper-level ridge positioned just to our east while upstream flow slows down. A longwave trough is forecast to move into the northern Plains and Canadian Prairies Monday night into Tuesday which may bring another chance of showers to the Northland. A possible complicating factor is the poleward moisture stream from Hurricane Polo. Moisture from that system could slip around the southern periphery of the Rockies and spill into the Plains and Midwest ahead of the Tuesday system which could set the stage for greater rain chances as the trough moves into our area. Models struggle to handle the breakdown of blocking patterns once they are established. We will need to keep an eye on that time frame in case the potential for widespread precipitation emerges.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 635 PM CDT Thu Sep 24 2026

A line of light showers continues to fade across the Northland with lingering pockets of showers expected through the early evening hours. Widespread IFR/LIFR ceilings are slowly moving in from the west and will envelope all the terminals through the overnight hours expect for HYR. Areas of fog could also develop in the early morning hours. There is some signal for a layer of fog off of Lake Superior to attempt moving up the hill towards DLH in the morning hours as well. Low ceilings are expected to linger through the morning hours tomorrow with some improvements as we head into the afternoon.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 250 PM CDT Thu Sep 24 2026

Light east and northeast winds of 5 to 10 knots are forecast this evening with wave heights of 1 to 2 feet. Light rain will move over portions of the southwest arm of Lake Superior through this evening. There may be enough rain to support fog development overnight. For now we are keeping the fog potential limited in the forecast. Wind speeds are expected to remain in the 5 to 10 knot range for Friday and will be variable in direction changing northeast with time during the afternoon. High pressure will be located east of the lake on Saturday with low pressure over the central Plains. Look for northeast winds to strengthen, particularly in the southwest arm, to around 10-15 knots with gusts up to 20 knots. There is a small chance conditions will become hazardous to smaller vessels during that time. Winds are forecast to veer southerly on Sunday as high pressure drifts southeastward over lower Michigan. Slightly stronger winds are possible Monday and Small Craft Advisories may be needed by Tuesday afternoon through Wednesday as a stronger system moves across the region.

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

FIRE WEATHER

Issued at 250 PM CDT Thu Sep 24 2026

No fire weather concerns expected through early next week. Winds will be from the south Friday with highs in the middle 60s to low 70s and afternoon RH values between 50 and 80 percent. Southerly winds persist through Sunday. Rain chances return Saturday into Saturday evening mainly over central and north- central Minnesota. Up to a tenth of an inch of rain is forecast. Temperatures Saturday will be in the low 60s in central Minnesota to the middle 70s for portions of northwest Wisconsin. Afternoon RH values will be driest over northwest Wisconsin where values between 40 and 50 percent are forecast. Look for afternoon RH above 50 percent elsewhere. Seasonal temperatures in the 60s and low 70s are expected Sunday with RH values in the 55 to 75 percent range. There will be additional rain chances 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.