textproduct: Duluth

KEY MESSAGES

- Breezy northerly to northwesterly winds will lead to near- critical fire weather conditions in northeastern Minnesota through early this evening.

- Cooler today with lingering sprinkles and isolated rain showers this afternoon. Very little to no accumulation expected.

- Drier with more seasonable temperatures on Wednesday, then gradually warming up again and becoming hot next weekend.

DISCUSSION

Issued at 220 PM CDT Tue Jul 21 2026

Today - Tonight:

A secondary cold front is moving southward through the Northland this afternoon with weak cyclonic flow behind it. There is just enough low-level moisture in this pattern to produce intermittent sprinkles and a couple very light rain showers this afternoon in portions of northeast Minnesota and northwest Wisconsin, but very little to no rain accumulations are expected. Otherwise, partly to mostly cloudy skies continue through early evening alongside northerly to north-northwesterly winds gusting to 20-30 mph and substantially cooler high temperatures in the mid-60s north to mid-70s south relative to what we have been seeing recently. Despite relatively higher minimum relative humidity values of 40-50% this afternoon, the stronger winds set the stage for near-critical fire weather conditions in much of northeastern Minnesota through early evening.

Much more comfortable low temperatures in the mid-40s to around 50 degrees settle in tonight alongside calm to light and variable winds and clear to mostly clear skies.

Wednesday - Early Thursday:

High pressure sliding through the region on Wednesday into early Thursday will keep the weather during this timeframe dry with mild conditions continuing. Some scattered diurnal cumulus develops mid/late Wednesday morning into early evening, otherwise conditions will be mostly clear. High temperatures on Wednesday will be seasonal in the low to upper 70s, with Wednesday night lows in the upper 40s to mid-50s.

Late this Week - Weekend:

The upper-level pattern becomes amplified late this week into weekend with broad mid- and upper-level ridging over the western U.S. and a trough over eastern Canada/eastern U.S. This will set up northwest flow over the Upper Midwest in which a few shortwave troughs could move through the region while temperature trends will be on the rise. The first round of precipitation potential would be a 10-40% chance for in far northern Minnesota--mainly north of the Iron Range--late Thursday and Thursday evening. The better chances (30-80%, highest across northern Minnesota) would be with another shortwave trough and attendant surface front Friday evening into Saturday morning. There are additional, low-end shower and storm chances (20-40% chances) on Saturday and Sunday, but confidence is lower as to the timing and southward extent of any shortwave troughs rounding the top of the ridge into the Northland due to the closer proximity of the mid/upper-level ridge axis by that time. Depending on how quickly the cold front clears the Northland on Saturday, there could be a brief window of time late Saturday where an instability/shear combination could support strong to severe storms. There is also a weak signal for strong to severe storm potential on Sunday, but confidence in potential and locations is low at this time. Regardless, there is not a strong signal for widespread precipitation amounts over the next 7 days, with probabilities of >0.25" through the weekend ranging from 50-60% in the Iron Range and north to 30-40% in much of northeast Minnesota and northwest Wisconsin and 20% in central Minnesota.

High temperatures gradually warm from the low to mid 80s on Thursday to mid-80s to low 90s on Saturday and Sunday, though onshore flow/lake breeze on Sunday would likely keep the hottest conditions away from Lake Superior. Still, this heat would likely lead to Heat Advisory for portions of the Northland this weekend. These hotter conditions combined with fairly low relative humidity and breezy conditions at times could lead to a return of elevated fire conditions for Friday into this weekend.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1243 PM CDT Tue Jul 21 2026

SCT to BKN VFR conditions in cumulus and stratocumulus are expected through the afternoon hours, with highest coverage in the Minnesota Arrowhead, far northern Minnesota, and northwest Wisconsin. Intermittent sprinkles/light rain showers continue into this afternoon as a weak cold front/surface trough moves through, with best potential at KINL and KHIB. North-northwest to northerly winds at 10-15 kt and gusts of 20-25 kt persist through early evening then quickly weaken towards sunset. Diurnal cloud cover decreases this evening and winds become light and variable to calm tonight as high pressure moves into the region. Additional VFR diurnal cumulus is expected to develop late in the current TAF period with light northwest winds on Wednesday.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 220 PM CDT Tue Jul 21 2026

Gusty northwest to northerly winds of 10-15 kts and gusts of 20-25 kts continue through the remainder of this afternoon across western Lake Superior nearshore waters, and linger into early evening from Taconite Harbor to Grand Portage and in the Apostle Islands to Saxon Harbor. Small Craft Advisories are in effect. Winds quickly diminish this evening out of the northwest to 5-15 kts as high pressure builds into the area. Southwesterly winds are expected for Wednesday through Thursday and into the weekend at 5 to 15 kts, though there may be brief afternoon gusts around 20 kts along the North Shore from mainly Grand Marais to Grand Portage Wednesday and Thursday afternoons. Southwest winds of 10-15 kts and gusts of 20-30 kts are possible on Friday, which bring better chances for a return of hazardous conditions for small craft.

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

FIRE WEATHER

Issued at 220 PM CDT Tue Jul 21 2026

Scattered to broken cloud cover continues the rest of the afternoon into early evening along with spotty sprinkles/very light shower chances for the remainder of the afternoon (20% chance or less). Very little to no accumulations expected. Minimum afternoon RH values will fall into the 40 to 50% range, lowest in central Minnesota east into the Northwest Wisconsin Pine Barrens. Winds will remain breezy from the north at 20-30 mph through late this afternoon, then quickly weaken early this evening and becoming calm to light and variable tonight. Cooler high temperatures in the mid-60s to mid-70s this afternoon drop into the mid-40s to around 50F tonight along with RH recovery of 85-90% or higher.

High pressure moves in for Wednesday and early Thursday with primarily sunny and rain-free conditions, with highs in the 70s on Wednesday and low to mid 80s on Thursday. Minimum afternoon RH values bottom out in the 30 to 40% range both days. There is a 10-40% chance for a few showers/thunderstorms in far northern Minnesota late Thursday afternoon and evening, but limited precipitation amounts are expected. A cold front Friday evening into early Saturday brings better precipitation chances (30-80%, highest in northern Minnesota), but forecast amounts are on the order of a quarter inch or less (locally higher where thunderstorms move overhead). Otherwise, no significant rain chances are expected through this weekend. Temperatures warm back into the 80s and 90s for the weekend with breezy conditions possible both Friday and Saturday that, when combined with the heat and breezy winds and fairly low RH, could lead to a return of elevated fire weather conditions.

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 7 PM CDT this evening for LSZ121- 140-141-147-148-150. Small Craft Advisory until 4 PM CDT this afternoon for LSZ142>146.