textproduct: Duluth

KEY MESSAGES

- Drier with seasonable temperatures today, then gradually warming up again and becoming hot this weekend. Heat Advisories may be needed for portions of the Northland Saturday through Monday.

- Breezy winds, fairly low relative humidity, and hot conditions could lead to elevated fire weather conditions for portions of the area on Friday through this weekend.

- A cold front Friday afternoon and night brings our best chance for thunderstorms, with a sliver of a slight (level 2 out of 5), severe threat in north-central Minnesota, mainly for large hail.

DISCUSSION

Issued at 151 AM CDT Thu Jul 23 2026

Generally quiet weather is affecting the Northland early this morning, with high pressure centered over southern Minnesota. We have light west to southwest winds, and mostly clear skies across the area. Some storms that developed earlier this evening over northwest Ontario where instability and shear were sufficient for storm development have been drifting southeast towards the Arrowhead. However, as the environment is much less favorable here, they have been weakening to little more than showers as they cross the border. As we head through today, expect mostly sunny skies and seasonable temperatures climbing into the low to mid 80s. This afternoon and evening we will get additional shower and storm development over northwest Ontario which may drift into the Borderlands. Have kept some small precipitation chances going for these storms through the afternoon and evening. Light winds will gradually turn to the southwest and increase a bit by the afternoon. The overnight hours tonight will be quiet and mostly clear with comfortable lows in the upper 50s and lower 60s.

Friday afternoon and night marks our best chance at showers and thunderstorms through this forecast period. A shortwave will move across the flattened ridge over the western CONUS and across the Northland Friday night. Ahead of it, southerly flow will push in a noticeably warmer and more humid airmass, pushing highs into the mid to upper 80s. A cold front which accompanies the shortwave will approach from the northwest late Friday afternoon into Friday night. Instability and shear profiles ahead of the front suggest a few elevated supercells could develop across northwest and north central Minnesota late Friday. These storms will carry a level two out of five risk for severe weather, with large hail up to ping pong ball size and isolated damaging wind gusts being the primary hazards.

Behind the departing front on Saturday, the predominant weather concern shifts to heat. The upper ridge will amplify and shift east, allowing temperatures to soar into the upper 80s and low to mid 90s. With dew points remaining elevated, heat index values will climb into the 90s. If this trend holds, Heat Advisories may be needed for portions of the Northland Saturday through Monday. Precipitation chances diminish for Saturday, but then a mid level baroclinic zone and convergence draped across the area may bring showers and thunderstorms to the area Sunday and Sunday night. These precipitation chances are somewhat conditional, as warm temperatures aloft may suppress any widespread convection.

The unseasonably hot and humid conditions will persist into early next week, with Monday likely seeing another day of widespread upper 80s and low 90s across the area. A slight chance of showers and thunderstorms will linger Monday into Tuesday, but confidence remains low on exact timing and coverage as most of the region remains capped under the strong upper level ridge and warm temperatures aloft. By the middle of next week, the pattern suggests a slight moderation in temperatures back toward the 80s, but overall conditions are expected to remain warmer than normal for late July with relatively sparse precipitation.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 640 AM CDT Thu Jul 23 2026

Mainly expecting VFR conditions through the period. There is a ~5% chance for a stray shower or storm at INL this afternoon, but it's low enough of a chance not to include in the TAF. Expect breezy southwest winds at DLH/HIB/INL today in the 15-20 kt range. Winds are expected to subside around sunset, becoming light for the most part. One potential exception is around INL, where some breezy conditions could persist. A LLJ is expected to develop tonight, so LLWS is possible. The highest confidence is at INL, so that's where I included a bit of LLWS in the TAF at this time.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 151 AM CDT Thu Jul 23 2026

Southwest winds will increase once again today to 15 to 25 knots, particularly along the North Shore and around the Apostle Islands. Waves will build to 3 to 5 feet along the North Shore north of Grand Marais. Another Small Craft Advisory has been issued for these areas for today and this evening. Another round of stronger southwest winds is anticipated for Friday into early Saturday ahead of an approaching cold front. This is likely to bring building waves and potentially 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 446 AM CDT Thu Jul 23 2026

There is a 10-20% chance for isolated showers and perhaps a stray storm in far northern Minnesota near the International Border this afternoon. Rainfall of a few hundredths is most likely wherever it rains, but locally higher amounts up to a tenth of an inch or two may be possible in a storm. This activity is expected to be very localized this afternoon, if it happens at all. Minimum RH today dips to 30 to 40% along with high temperatures in the low to mid 80s and southwest winds of 5-10 mph with daytime gusts of 15-20 mph. RH recovers above 80-90% again tonight.

A cold front late Friday into early Saturday brings better precipitation chances (30-90%, highest along and north of the Iron Range). Forecast rainfall amounts with these scattered showers and thunderstorms are mostly 0.2-0.5" north of the Iron Range, 0.1-0.2" for the Iron Range, and 0.1" or less south of the Iron Range. Locally higher amounts to around 0.75-1.00" could be possible along the International Border areas due to thunderstorms (~30-50% chance). Portions of north-central Minnesota could also see a few strong to severe storms with large hail, damaging winds, and frequent lightning late Friday afternoon and Friday night. Otherwise, no significant rain chances are expected through this weekend into early next week. Temperatures warm back into the 80s and 90s for the weekend into Monday with breezy conditions possible mainly on Friday that, when combined with the heat and fairly low RH of 35-45% for much of the Northland, could bring about 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 from 10 AM this morning to 10 PM CDT this evening for LSZ140-141. Small Craft Advisory from 10 AM this morning to 4 PM CDT this afternoon for LSZ142-143-146-147-150.