textproduct: Duluth

KEY MESSAGES

- On and off chances of storms are expected through the weekend and into next week. A few strong to severe storms are possible from the Brainerd Lakes to northwest Wisconsin this afternoon and evening.

- Warm temperatures continue today before a brief cooldown for Saturday (Independence Day). Temperatures warm up again Sunday and early next week.

- Independence Day Outlook: Showers and thunderstorms are possible during the day and evening. Severe weather is not expected. Expect highs around 80 inland and 60s to 70s near Lake Superior. Gusty easterly winds in the Twin Ports may create dangerous swimming conditions and hazardous conditions for small craft.

DISCUSSION

Issued at 316 AM CDT Fri Jul 3 2026

A weak cool front stretched from the Arrowhead to near Cass Lake as of 07Z. A nearly-stationary front was found slightly farther south near Duluth to somewhere around Brainerd. A broken line of thunderstorms continued to percolate along the cool front. A broad area of surface high pressure was building southward from far northern Ontario. The latest RAP analysis revealed a subtle shortwave trough over the western Dakotas behind two areas of thunderstorms, one in northern North Dakota and the other in central and southern South Dakota. CAMs are struggling to capture the magnitude and location of ongoing convection, which has been the case for the past several nights. That leads to an overall low confidence in the precip chances for the next several hours.

The chance of showers and thunderstorms will persist along the cool front through the morning hours. CAMs tried to extinguish the convection within a few hours. That has been the case the past several nights and thus I put low weight into that signal. MUCAPE values of 500-1250 J/kg were found near the cool front as of 07Z and should persist through the night. Moisture advection into the frontal zone is weak and 0-6 km bulk shear is less than 25 knots. Therefore severe storms are not expected during the early morning hours. Locally heavy rainfall and small hail are likely with the storms.

Attention then shifts to the daylight hours. Showers and storms may continue to percolate along the cool front through the morning. By late afternoon MLCAPE values south of the cool front of 1000-3000 J/kg are forecast with limited MLCIN with 0-6 km bulk shear values of 25-35 knots depending on which model you view. Weak winds across the Northland create an unimpressive hodograph with limited veering and speed shear in the lowest 3 km. Thus it appears upright pulse storms may be the mode de jure. Downdraft CAPE of 600-1200 J/kg will support a potential for microburst winds of up to 60 mph. Penny size hail is the most likely max size, although a rambunctious storm or two could drop a few quarters like we saw last evening. Sub-severe storms are the more likely outcome for today and tonight. As such, we agree with the somewhat broad Marginal (level 1 of 5) risk for severe storms inland from Lake Superior.

Temperatures will still be quite warm today with highs in the low to upper 80s. Heat Risk values stay in the "low" category for most areas today (https:/www.wpc.ncep.noaa.gov/heatrisk). Forecast WBGT values will be in the upper 70s to low 80s with heat indices in the 80s to low 90s. The only parameter which meets local Heat Advisory criteria is the WBGT forecast, so we will forego a Heat Advisory at this time.

There is a small concern about northeast winds over western Lake Superior strengthening this afternoon and posing a risk of rip currents for the beaches of the Twin Ports. With the cool front progressing a little slower than forecast yesterday afternoon, think the increase in winds over the water will be slower and a lower magnitude. As such the overall risk of rip currents today is low. We will need to monitor the surface winds through the early afternoon in case they are able to strengthen more than forecast due to convective latent heat release and associated surface pressure perturbations.

Convection will likely persist into tonight although confidence in timing and placement remain low. Thus opted to carry a broad-brushed risk of showers and storms overnight. The 03.00Z model suite indicates a convectively enhanced shortwave trough will propagate northeastward out of the central Plains tonight and Saturday morning, which will bring a broad chance of showers and storms. There are a lot of silent "ifs" in that forecast depending on the strength and location of the storms in the Plains tonight and early Saturday morning, along with convective influences from storms ongoing across the Dakotas, Nebraska, and Iowa early this morning. Pulled back a bit on the NBM PoPs and limited them to 40% for Saturday. Later updates may have a better handle on the convective evolution today and tonight.

One aspect of the forecast for Independence Day which has higher confidence is the wind forecast over western Lake Superior. High pressure over northern Ontario will sag southward during the day which will tighten the pressure gradient over the lake with a favorable orientation for strong northeast winds. Unfortunately that will lead to a higher risk of rip currents for the holiday and a Beach Hazards Statement may be needed.

Sunday into next week: It's possible we might end up with brief surface high pressure on Sunday following the potential low on Saturday. Following that, it's looking like a continuation of warm and active weather into next week. We will likely have some warm spells with intermittent shots at showers and storms.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 619 AM CDT Fri Jul 3 2026

Reduced visibility in fog and mist will dissipate quickly this morning leaving VFR conditions until tonight. There is a 30% chance of thunderstorms impacting BRD this evening. Probabilities were too low to include PROB30s at HYR. Mist and fog are expected to develop once again tonight producing MVFR to LIFR visibility.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 316 AM CDT Fri Jul 3 2026

The main concern for today is a few isolated to scattered thunderstorms over western Lake Superior which may produce wind gusts up to around 30 knots and small hail. Winds will turn northeasterly although they should remain relatively weak. As high pressure settles southward over northern Ontario, the pressure gradient over western Lake Superior will tighten with a favorable orientation for strong northeast winds. Small Craft Advisories may be needed for Saturday, particularly over the southwest arm of Lake Superior down to the Twin Ports. There is a about a 20% chance of isolated thunderstorms again Saturday though severe storms are not anticipated. There will be off and on chances of storms during the next week. After Saturday the potential for strong winds over the water diminishes and no additional headlines are anticipated at this time.

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

FIRE WEATHER

Issued at 316 AM CDT Fri Jul 3 2026

Warm weather persists today before trending a little cooler for Independence Day. RH values will bottom out in the 40s and 50s. Temperatures trend warmer and RHs trend slightly drier Sunday into early next week. There will be periodic chances of showers and storms through the weekend. Widespread wetting rain is not anticipated at this time. However, some models indicate widespread rain potential for Saturday. As of now, a more conservative forecast with lower rain chances and precipitation amounts seems appropriate. A prominent lake breeze is forecast Saturday which will affect the I-35 corridor and northwest Wisconsin. Overall fire weather concerns are low at this time.

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.