textproduct: Duluth

KEY MESSAGES

- A decreased severe threat remains for our far southern Wisconsin areas this evening, with a primary risk of two inch golf ball hail and localized, minor flooding possible along portions of the South Shore.

- More storms are expected tomorrow afternoon but will mainly stay to our south, though a few could clip our southeast with small hail.

- An active pattern continues, with a couple more chances for showers and thunderstorms and even some light snow over the weekend.

DISCUSSION

Issued at 101 PM CDT Mon Apr 13 2026

A thick deck of low stratus lingers from morning fog over northeast Minnesota and along the South Shore of northwest Wisconsin. This cloud cover, combined with a small line of light showers currently moving northeast in northwest Wisconsin and soon to reach Pine County, will prevent the favorable severe weather environment from reaching most of the area. However, a targeted severe threat remains this evening for our far southern Wisconsin zones, particularly around Price County. The main hazard will be large hail up to two inches in diameter due to a very deep hail growth layer aloft. The tornado and wind threat has dropped significantly as storms will struggle to remain surface based, but a few strong gusts or a brief tornado cannot be completely ruled out if a storm moves up from the south before elevating. Additionally, a localized flash flood risk continues tonight across the South Shore as more rain falls on saturated soils and remaining existing snowpack.

Moving into tomorrow, another round of storms is expected in the afternoon, but the bulk of this activity will remain to our south. A few strong storms could clip our southeastern areas and produce small hail. Meanwhile, a broader upper level trough and surface boundary will bring scattered light rain showers across northern Minnesota throughout the day. Temperatures will remain relatively cool, topping out in the 40s and 50s across the region with light easterly winds shifting to the northwest by the late afternoon.

The active weather pattern continues into Wednesday as another deep trough in the Central Plains sends a warm front lifting towards the Northland. This system has shifted south, and most showers and storms will once again stay to our south. However, there is a small chance that some weak instability may reach our southern CWA border, and a few thunderstorms producing small hail cannot be ruled out. Temperatures will begin to moderate, reaching the upper 50s and mid 60s for most locations, accompanied by a steady southeast wind.

By Thursday, the region gets a brief and partial break, though a few lingering rain showers remain possible, especially in the morning. Temperatures will continue their upward trend, with afternoon highs reaching the 60s up to 70 degrees under partly sunny skies.

Friday looks to be highly dynamic as a large, elongated system pulls Gulf moisture northward into the Upper Midwest. Southerly winds will increase, bringing warm air and pushing high temperatures into the upper 60s and lower 70s. This influx of warm, moist air will lead to widespread rain and another potential round of severe thunderstorms during the afternoon and evening hours as a strong front passes. A quick change arrives for Friday on the back of the system. Strong northwesterly winds will bring in a much colder airmass, sending overnight lows falling back below freezing Friday night. Lingering moisture wrapping around the departing low will likely transition from rain to scattered snow showers or rain/snow mix into Saturday. Since we've been warm lately, the ground will be warm enough that very little snow accumulation is expected, if any. The exception would be isolated areas of higher snowfall rates, though that remains uncertain at this time. High temperatures will struggle to reach 40 degrees. Fortunately, the chill is short lived, with sunny skies and temperatures rebounding into the 50s by Sunday.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1227 AM CDT Tue Apr 14 2026

Thunderstorm complexes are well off to the southeast this morning with radar showing some scattered rain showers still floating across the Northland, primarily over northern MN. Mostly VFR conditions to start the forecast period but easterly winds off Lake Superior is expected to spread a marine layer over much of the region lowering clouds to LIFR and producing fog. This layer is largely expected to remain in place through the day. There will also be some additional rain that comes through northern MN in the morning.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 101 PM CDT Mon Apr 13 2026

Northeast winds will persist over Western Lake Superior into Tuesday as low pressure passes to our south. Small Craft Advisories remain in effect due to wind gusts up to 25 knots and waves building to 4 feet, particularly along the North Shore and Outer Apostle Islands. Winds will gradually ease and become variable by Tuesday night before shifting easterly on Wednesday.

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

FIRE WEATHER

Issued at 101 PM CDT Mon Apr 13 2026

No critical fire weather conditions are expected in the near term. An active weather pattern will keep the region wet with multiple rounds of showers and thunderstorms through the week. Relative humidity values will remain well above 30%, and winds will generally stay under 15 mph through Thursday before increasing on Friday from the south.

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

HYDROLOGY

Issued at 342 AM CDT Mon Apr 13 2026

Over the past 72 hrs we have had a few swaths of 0.25-0.50" over our existing snowpack into the Arrowhead and the South Shore. The highest swatch of over 1" ran through Sawyer into southern Ashland and Iron Counties. There is still some potential for storms to develop late this afternoon and evening and move across our Flood Watch counties, but chances have decreased as the warm front that will be the focal point for storm initiation is projected to be farther south. Additional rainfall of around 0.50" will be possible with locally higher amounts should any storms develop. Tuesday's activity also looks to be more light rain focused on northern MN. With this in mind we have opted to shorten the duration of the Flood Watch to Tuesday morning.

An impressively warm day for Sunday has help to melt more of the snow pack. The South Shore saw temperatures climb into the 60s and 70s. And even the North Shore got in on some of the warmth action with highs capping out in the 50s. Modeled snow depth across the South Shore saw a significant decrease losing as much as 8" in just 24 hrs. The North Shore's >24" foot print has also been reduced from the Arrowhead to mainly the high terrain of the North Shore. It's hard to know the extent of how much water this has returned to the soil but across the South Shore it is likely in excess of 2".

Taking a trip through some of river gauges does show some response to this added liquid from snow melt. Across the MN sites the river heights have increase 0.5-1.0' NW WI where we saw the more impressive melting has seen rises of 2-3' across several rivers. The Tyler Forks River near Mellen WI is still the primary concern with a Flood Warning already in effect. This river is expected to crest on Tuesday morning just below moderate flood stage and move out of minor flooding Thursday.

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...Flood Watch until 7 AM CDT this morning for WIZ002>004. MARINE...Small Craft Advisory until 8 AM CDT this morning for LSZ140- 141. Small Craft Advisory until 1 PM CDT this afternoon for LSZ142>147-150.