textproduct: Duluth

KEY MESSAGES

- Critical and near-critical fire weather expected this afternoon and early evening for portions of north-central and northeast Minnesota.

- Very warm temperatures (60s and 70s) away from Lake Superior today with dry air and gusty winds.

- Rain and thunderstorms Friday afternoon and early evening with isolated to scattered severe storms possible along I-35 and east into NW WI. All hazards are possible.

- Colder into the weekend, but chances for accumulating snow have decreased. Warmer temperatures return through next week.

DISCUSSION

Issued at 157 AM CDT Thu Apr 16 2026

Dense fog continues this morning over and near Lake Superior. Much of this fog should start to burn off and retreat back to the coast through this morning. Southerly flow brings even more robust WAA today, with afternoon high temperatures expected to reach into the upper 60s to mid 70s for most of the area. This will lead to a drastic temperature differential with Lake Superior and a fog bank may linger over the lake through the day and could affect coastal areas at times.

Warm temperatures and good low level mixing is expected to lead to a very dry afternoon with minimum RH of 20-30% and breezy south winds with gusts of 20-30mph today. This will lead to some near critical fire weather conditions with a SPS out for areas in north-central and NE MN (not including the Arrowhead where conditions should stay more moist).

A low pressure system across the High Plains will track eastward on Friday as a longwave trough amplifies over the central CONUS. That will bring surge of warm and moist air across the Upper Midwest, while drier moves on top of it. This will set the stage for thunderstorms and potential severe storms Friday afternoon and evening ahead of an approaching cold front. This system has trended north just a tad, allowing a nose of instability and moisture further into the Northland. Timing is such that the cold front is expected to be around I-35 by midday, largely confining the severe threat to I-35 corridor and east with the highest threat (Slight risk, level 2/5) from Spooner to Hayward to Ironwood and southeast. Recent model soundings have trended to become more surface based in NW WI, increasing the threat of not only hail and damaging winds but tornadoes as well, especially for Sawyer and Price county. Any severe weather should be fairly progressive and move eastward quickly as the cold front moves into the UP. Thunderstorms could start to develop from 12-3pm and push east, with most guidance showing the best storm environment out of our area by 00z Saturday (7pm Friday). Any thunderstorms could be capable of producing some locally heavier rain up to 1". Flooding concerns are fairly minimal with the progressive nature of this system, but extra water will likely keep things wet in NW WI with high streamflows. Rain over melting snow on the North Shore will also keep streamflows high there but widespread flooding concerns are not expected at this time.

A decent blast of CAA follows this system with winds turning around to the NW Friday evening into Saturday. Guidance suggests that these NW winds could get fairly breezy and strong along the North Shore where gusts in excess of 30-40mph are possible. Much cooler conditions this weekend will result in a return to overnight lows below freezing and afternoon highs in the 30s and 40s. With the northward trend of the low pressure system Friday however, snow potential has decreased. Those along the border and in the MN Arrowhead might see a trace of accumulation with flurries elsewhere. Ridging returns next week, bringing temperatures back into the 40s, 50s, and 60s in the afternoon. Most global guidance doesn't show our next widespread chance of precipitation until late next week into the weekend.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 107 PM CDT Thu Apr 16 2026

VFR conditions are forecast this afternoon into this evening. A strong southerly low-level jet will bring a potential for low- level wind shear to the terminals overnight and early Friday morning. Low pressure over the northern Plains will move farther east tonight with high clouds developing. A cold front will move into western Minnesota Friday morning and ceilings will lower to MVFR at HIB, INL, and BRD before 18Z. There may be a few rain showers moving through those terminals. I introduced a PROB30 at INL and at BRD for the most likely times of precip. After 17.18Z widespread rain showers and thunderstorms are forecast as the cold front pushes farther east. Expect low ceilings and visibility near and behind the front.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 157 AM CDT Thu Apr 16 2026

Breezy northeast winds are expected to develop through the day today, with some afternoon gusts up to 20 knots possible at the head of the lake. This period will need to be monitored for a possible marginal Small Craft Advisory. A fog bank is expected to still around over Lake Superior through the day today and the Marine Dense Fog Advisory has been extended through this evening. Into Friday, northeast winds continue through the morning, and then become northwest through the afternoon. Gusts of 20-30 knots are possible Friday and additional Small Craft Advisories may be needed. Stronger northwest winds with possible gale-force gusts are possible along the North Shore going into Saturday. Thunderstorms are expected Friday afternoon and early evening which may bring gusty and erratic winds, hail, and brief heavy downpours.

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

FIRE WEATHER

Issued at 107 PM CDT Thu Apr 16 2026

Updated planning forecast for lower RH values this afternoon into early evening. A Red Flag Warning was issued for north and south Cass County. Expect dewpoints and relative humidity to fall quickly this morning. Minimum RH values will be between 20 and 30 percent over most of the Northland with the exception of areas in the Minnesota Arrowhead (specifically due north from Duluth to the Canadian border and areas to the east). Wind gusts more than 25 mph are forecast over portions of central Minnesota. Cass County will experience about 6 hours of Red Flag criteria while nearby areas will see spotty locations with an hour or two of Red Flag conditions. Wind gusts will end this evening and RH values will recover by about 8 PM.

PREVIOUS DISCUSSION... Issued at 157 AM CDT Thu Apr 16 2026

Much above normal temperatures enter the Northland today and Friday. Warm temperatures (highs of 65-75F) and good low level mixing is expected to lead to a very dry afternoon with minimum RH of 20-30% and breezy south winds with gusts of 20-30mph. This will lead to some near critical fire weather conditions with a SPS out for areas in north-central and NE MN (not including the Arrowhead where conditions should stay more moist). A stout lake breeze boundary is likely to set up around Lake Superior. Winds pick up into Friday and temperatures stay warm, but an incoming system should improve moisture. Thunderstorms, some possible severe, are expected Friday midday through early evening. All hazards are possible in severe storms and some locally heavy rain is possible, most likely in NW WI. On the back side of that system, some very light snow may fall into Saturday.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Red Flag Warning until 8 PM CDT this evening for MNZ025-033. WI...None. MARINE...Dense Fog Advisory until 7 PM CDT this evening for LSZ140>142.