Image credit: National Weather Service, Twin Cities/Chanhassen office
A complex weather system enveloped Minnesota from October 23 into early on the 28th, producing scattered heavy thunderstorms with intense rainfall, waves of steady rain, strong winds, and even some accumulating in far northwestern and northern parts of the state.
The first activity began late on Monday October 23, as a small area of thunderstorms with vivid lightning, downpours, and small hail tracked across southern Minnesota, generally south of the Twin Cities area. Rainfall totals of a half-inch to an inch were common from Mankato, to Waseca, to Rochester, to Winona.
The overnight and early morning activity moved away and dissipated on Tuesday morning, as a much more humid air mass spread into southern Minnesota from Iowa. Temperatures rose into the low 70s F and dew points sailed into the 60s F, destabilizing the atmosphere and allowing strong thunderstorms to develop. Two storms in particular developed intense hail cores, with hail up to tennis ball size (2.50 inches in diameter) and damage to windshields reported near Sleepy Eye in Brown County, with other large hail reported near Springfield and Cobden.
Elsewhere, scattered thunderstorms spread across much of southern Minnesota, occasionally producing heavy rain. The thunderstorm activity eventually gave way to bands of moderate rain, which continued through the night. By morning, and additional 0.5 to two inches of rain had fallen over the southeastern third of the state, including the Twin Cities area. The heaviest totals were again in Winona County, where 3-4 inches of rain fell, with similar amounts south of Rochester and also around Lake City.
A general lull in the precipitation set in on Wednesday October 25th, as the energy and moisture supporting the unsettled weather moved out of the region. However, a new batch of moisture with a developing low-pressure area and cold front moved in, kicking off more steady rain late in the evening and into Thursday morning. As the cold air streamed into Minnesota, accumulating snows developed across the far northwest and north. Lake Bronson reported 8.2 inches of snow, with 6.2 inches in Thorhult, 5.2 inches at Warroad, and 4.5 inches at Norris Camp. International Falls reported 3.5 inches of accumulation for the event.
The wind shift brought strong northerly gales to Lake Superior, with numerous cold-water surfers attempting to catch the 8-foot waves near Park Point in Duluth. Scattered showers and snow generally decreased in coverage and intensity, but continued off and on across the state into the early weekend. Precipitation totals for the entire period were generally an inch or more over the southeastern half of the state, with amounts of 2-3 inches from scattered near the Twin Cities, Le Sueur, Red Wing, and Rochester. Totals of 4-7 inches were observed from southeast of Rochester over towards Winona.
The northwestern quarter of the state also saw precipitation totals of an inch or more. The least precipitation, generally under 0.75 inches, stretched east-northeastward from Ortonville and Moorhead, through Grand Rapids and towards the north shore of Lake Superior.
Nov 1, 2023