Image credit: National Weather Service, Chanhassen office.
A large pool of atmospheric moisture associated with a developing and slow-moving weather system delivered some badly needed rains to much of Minnesota from Friday June 23, 2023, and through the weekend. Most of Minnesota received a half-inch of rain or more, a few chunks of the state received 1.5 inches or more, and for the most part, the developing drought was held at bay for a week.
Thunderstorms and summer-like rain showers developed on Friday June 23 across much of Minnesota, continuing into the evening and overnight, with some heavy rains in the north and northeast. On Saturday, more widespread thunderstorms covered much of southern, central, and eastern Minnesota, never all at once, but in waves large enough to hit many areas. Some of these produced downpours lasting 15-30 minutes and this "convectively active" behavior continued through the night.
Separately, a band of steady moderate to heavy rain formed across northwestern and north-central Minnesota on Saturday, as a spoke of energy rotated around the rather tight circulation of the parent low-pressure center. Just south of this cyclonic rain band, additional thunderstorms formed, regenerated, back-built, and managed to remain concentrated in a small area near Mahnomen and north of Detroit Lakes, in an area where storm spotters reported a swarm of mostly small and relatively short-tracked tornadoes. These same thunderstorms produced copious rains, though over small areas, leading to localized flash-flooding.
On Sunday, the weather system passed to the east of Minnesota but most of the state remained in a humid residual air mass, and isolated showers and thunderstorms developed during the afternoon, with short-lived downpours lasting 5-15 minutes.
Most of Minnesota received a half-inch of rain or more, though parts of northwestern, central, and northeastern Minnesota received 1.5 to 3 inches of rain. The heaviest rains fell in in the Island Lake area, northwest of Duluth, where two CoCoRaHS observers reported 4.89 and 4.32 inches. Observers southwest of Brainerd, and also north of Hawley in northwestern Minnesota reported at least three inches of rain. The least rain fell in far west-central and far southeastern Minnesota, where observers reported a quarter-inch of rain or less.
June 28, 2023