textproduct: Duluth

KEY MESSAGES

- Rain showers during the current overnight hours become more isolated to scattered today.

- 10-20% chance of isolated storms Sunday afternoon-eve and Sunday night/early Mon AM.

- Summer-like heat arrives for Memorial Day and continues through much of next week, with high temperatures in the 80s for most inland locations. Some locations could see low-90s on Tuesday.

- Much of next week will be primarily on the drier and sunnier side, though there will be isolated shower/storm chances at times. Potential for near-critical fire weather conditions will need to be monitored closely each afternoon into early evening next week.

UPDATE

Issued at 336 AM CDT Sat May 23 2026

Added a 10-20% chance of storms to northwest Wisconsin Sunday afternoon and early evening. Instability is forecast to build as temperatures warm into the middle and upper 70s. Several deterministic models feature a few showers/storms percolating on the nose of the instability gradient. These storms are in addition to the small chance of storms from Isabella to near the Twin Ports to Bayfield Sunday afternoon.

MLCAPE of 500-1000 J/kg, 30-35 knots of 0-6km bulk shear, steep mid-level lapse rates around -7.5 C/km, and dry air aloft suggests a potential for penny to half-dollar size hail. The main limiting factor for storm development is a lack of forcing for ascent. Relatively weak low-level flow and very warm temperatures over the land may allow a lake breeze to push inland from Lake Superior during the afternoon, which may provide focus for ascent. High-res guidance does not indicate a lake breeze developing as of this morning. Forecast trends will need to be monitored in case the environment becomes more favorable for severe storms. As of early this morning, the potential for severe storms is less than 5 percent.

A strengthening LLJ over north-central Minnesota continues to support a 10% chance of thunderstorms Sunday night into early Monday morning. These storms are not expected to be severe.

DISCUSSION

Issued at 100 AM CDT Sat May 23 2026

Current Overnight - Today:

An upper-level trough across eastern North Dakota and attendant surface low tracking north along the western MN border during the current overnight hours will continue northward today into southern Manitoba and far northwest Ontario. The best synoptic forcing and shower coverage is currently in far northern MN, the Arrowhead, and portions of far NW WI. Can't rule out a few rumbles of thunder during the overnight hours, but the potential is low (10-20%) and mainly relegated to far NW WI. No severe weather is expected.

Rain showers become more isolated to scattered for today as the better forcing for ascent moves north with the low pressure, then exit to the east of the Arrowhead and north-central WI late this evening. Additional forecast rainfall amounts range from a few hundredths of an inch to around 0.15" in north-central MN and much of NW WI and 0.1-0.35" in the St. Croix River Valley north into the Arrowhead and far NE MN. Plenty of cloud cover hangs around today with breezy southeast winds in the morning becoming southwesterly behind the occluded front in the afternoon to early evening as it moves through. High temperatures inland from Lake Superior will warm into the 60s to low 70s, warmest south. Areas in the Twin Ports and along the North Shore/Arrowhead will see cooler highs in the 50s due to onshore flow from Lake Superior.

Strong onshore winds and wave heights to around 3-4 ft this morning into afternoon will once again create the potential for rip currents for Minnesota and Wisconsin Point Beaches today. A Beach Hazard Statement will likely be needed.

Sunday - Monday Morning:

Additional mid- and upper-level energy pinwheeling around the upper- level low could kick off additional isolated showers/non-severe storms across north-central MN into the Arrowhead from early Sunday morning into midday Sunday.

Otherwise, expect Sunday to be the start of a strong warming trend as southwesterly winds advect warmer air into the Northland. Look for widespread high temperatures in the 70s and pockets around 80F away from the immediate vicinity of Lake Superior, with slightly cooler temperatures near the Lake and for the North Shore under primarily sunny skies. Weak shortwave energy moving through largely zonal flow aloft later Sunday evening into early Monday morning combined with some instability aloft and 30 kt of bulk shear could kick off some scattered, elevated showers and storms.

With warmer temperatures and primarily sunny skies for many areas on Sunday, low relative humidities could lead to near-critical fire weather conditions as minimum afternoon relative humidities dip into the 25-35% range from the Brainerd Lakes east to inland NW WI. If heating and afternoon mixing exceed the current forecast, minimum afternoon relative humidities could dip below 25%. Daytime southwesterly wind gusts will also be breezy, but gusts should largely remain at or less than 20 mph.

Memorial Day through the Coming Work Week:

The summer-like heat really cranks up for Memorial Day and Tuesday, though hot temperatures will continue through much of next week. This is due to an anomalously strong ridge aloft moving over the central CONUS and Upper Midwest. High temperatures on Monday will be widespread 80s away from Lake Superior and slightly cooler near the Twin Ports and North Shore. Tuesday will be the hottest day with widespread high temperatures in the upper 80s to low 90s away from Lake Superior, with some relief in the Twin Ports and near Lake Superior given some weak easterly onshore flow. Both Monday and Tuesday have the potential to approach record high temperatures in several locations. Heat Advisories may be needed for portions of the Northland on Monday and particularly Tuesday.

Well-above average temperatures inland from Lake Superior are favored to continue into mid to late next week as some flavor of an omega blocking pattern sets up, keeping the ridge axis in place overhead. Temperatures will gradually decrease by a few degrees each day from Wednesday through the end of the week as winds turn more southeasterly to easterly While predominately sunny skies are expected each day next week and little to no forcing for ascent will be in the area, the hot days could set off some isolated pop-up showers and non-severe storms, mainly in the afternoon into evening hours during and on the tail end of peak daytime heating.

This combination of heat and primarily drier conditions could also reintroduce periods of fire weather concerns each afternoon into early evening through the coming week. While winds during this period should be on the lighter side with peak daytime gusts mainly less than 20 mph, forecast minimum afternoon relative humidity dipping to 25-35% each day in addition to many areas not being fully greened-up yet will need to be watched closely for near-critical fire weather potential.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 639 AM CDT Sat May 23 2026

Rain showers taper off this morning. Ceilings will trend a little lower with widespread MVFR conditions expected. Terminals may see IFR ceilings for a time this morning into the afternoon. Fog may develop early Monday morning if skies can clear overnight. Light winds are expected overnight.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 100 AM CDT Sat May 23 2026

Gusty east to northeast winds of 15 to 25 kt continue this morning and linger near the Twin Ports to Silver Bay into this afternoon. Wave heights of 2 to 5 ft gradually diminish throughout this morning and early afternoon. Small Craft Advisories remain in effect for the nearshore waters. Calmer conditions on western Lake Superior develop for the next several days as a substantial warming trend occurs into next week, setting up a stable marine layer.

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

FIRE WEATHER

Issued at 100 AM CDT Sat May 23 2026

While rain showers become more isolated to scattered for much of daytime Saturday, cloudy to mostly cloudy skies linger through the daylight hours today. Additional amounts will range from a few tenths to around 0.15 inches in north-central MN and much of NW WI, and 0.1 to locally 0.35" in the St. Croix River Valley north into the Arrowhead and far NE MN. This will likely quell fire weather concerns for today as minimum afternoon RH is forecast to dip to 45-50% in the NW WI Pine Barrens and above 50% elsewhere. Temperatures warming well-above normal for next week and a pattern largely favoring plenty of sunshine and mostly dry conditions aside from occasional, isolated showers and storms will bring back concern for potential near-critical fire weather conditions each afternoon into early evening. Most days will see minimum relative humidities dip into the 30s (%) over a large area, with pockets of sub 30% min RH values. This pattern should have largely less gusty conditions, with daily winds around or less than 10 mph and gusts under 20 mph during peak daytime mixing.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Beach Hazards Statement until 2 PM CDT this afternoon for MNZ037. WI...Beach Hazards Statement until 2 PM CDT this afternoon for WIZ001. MARINE...Small Craft Advisory until 10 AM CDT this morning for LSZ140- 145. Small Craft Advisory until 4 PM CDT this afternoon for LSZ141>144.