MINNEAPOLIS, MINNESOTA — A larger storm system remains on track to bring widespread 2 to 4 inch rain totals across the Upper Midwest from Friday morning through Saturday night, with the heaviest rainfall expected from southern Minnesota into central Michigan, according to a National Blend of Models, or NBM, forecast run at 15Z and valid through 1:00 p.m. CT on Sunday, September 20.
Larger Storm System Remains on Track to Bring Widespread Rain Friday Through Saturday Night
Forecasters say this system has held remarkably consistent through multiple model runs, keeping the same general track and rainfall footprint across the Upper Midwest for the extended period spanning Friday morning through Saturday night. Rather than a quick-hitting round of showers, the setup is expected to unfold as a multi-day rain event, with repeated waves of precipitation working across the same general corridor before the system finally clears the region by early Sunday.
Heaviest Rainfall Corridor Runs From Southern Minnesota Into Central Michigan
The core of the heaviest rainfall is forecast to run in a west-to-east band from southern Minnesota through central Wisconsin and into central Michigan, tracking directly across some of the region’s largest metro areas along the way. That corridor lines up closely with Interstate 94, cutting through Minneapolis, Appleton, Milwaukee, Grand Rapids and Detroit, making this stretch of the Upper Midwest the focal point for both the heaviest totals and the greatest potential for localized flooding concerns as the storm system moves through.
Minneapolis and Appleton Lead All Totals at 3 Inches or More
The two highest forecast totals on the map belong to Appleton, Wisconsin, at 3.49 inches, and Minneapolis, Minnesota, at 3.03 inches, the only two locations reaching 3 inches or more in this forecast run. Both communities sit near the heart of the outlined heavy rainfall corridor, and forecasters say the combination of a slow-moving system and repeated rounds of precipitation is what pushes totals in this specific stretch well above the surrounding region.
Milwaukee, Grand Rapids and Cleveland See Widespread 1.5 to 2.75 Inch Totals
Just outside that top tier, a wide band of communities across Wisconsin and Michigan is forecast to see totals in the 1.5 to 2.75 inch range. Grand Rapids, Michigan, is forecast for 2.74 inches and Milwaukee, Wisconsin, for 2.66 inches, while farther east, Detroit checks in at 1.45 inches and Cleveland, Ohio, at 1.55 inches. To the north, Escanaba, Michigan, is forecast for 1.25 inches, with Alpena coming in lighter at 0.85 inches as the heaviest rain stays focused farther south across the Lower Peninsula.
Des Moines, Davenport and Chicago Land in the 1.5 to 2 Inch Range
South and west of the primary heavy rain corridor, forecast totals settle into a more moderate 1.5 to 2 inch range. Des Moines, Iowa, is forecast for 1.95 inches, with Davenport at 1.55 inches and Chicago, Illinois, at 1.5 inches. Farther south, Sioux Falls, South Dakota, is forecast for 1.06 inches and Winner, South Dakota, for 1.3 inches, marking the southwestern edge of the more substantial rainfall totals tied to this system.
Lighter Totals Expected Across the Dakotas and Western Nebraska
Rainfall totals drop off sharply heading toward the western Dakotas and Nebraska, where the NBM forecast shows far lighter amounts. Bismarck, North Dakota, is forecast for just 0.09 inches, with Jamestown at 0.27 inches and Fargo at 0.39 inches. In Nebraska, Kearney is forecast for 0.44 inches and North Platte for 0.63 inches, while Colby, Kansas, comes in at 0.53 inches, underscoring just how concentrated the heaviest rain remains toward the eastern half of the outlined region.
Fort Wayne, Columbus and Indianapolis See More Modest Amounts to the South
Along the southern edge of the forecast area, totals ease considerably as the heaviest rain corridor stays focused farther north. Fort Wayne, Indiana, is forecast for 1.2 inches, with Peoria, Illinois, also at 1.2 inches, while Columbus, Ohio, comes in lighter at 0.89 inches and Indianapolis lighter still at just 0.22 inches. Kansas City and Maryville, Missouri, round out the southern edge at 0.57 inches and 1.02 inches respectively, marking the southernmost reach of any meaningful rainfall tied to this system.
Duluth and Marquette Mark the Northern Edge as Totals Ease Toward Canada
To the north, totals taper off heading toward the Canadian border, with Duluth, Minnesota, forecast for 0.67 inches and Marquette, Michigan, for 0.44 inches. Farther into Ontario, Sault Ste. Marie is forecast for just 0.01 inches, reflecting how sharply the heaviest rainfall stays concentrated across the southern Minnesota to central Michigan corridor rather than spreading broadly northward as the system moves through from Friday into Saturday night.
