Heavy Precipitation in November?

How common is heavy precipitation during November?

By summer's standards, "heavy precipitation" during November is exceptionally rare. While most places can expect a good 1.5 to 2-inch rainfall during most summers, those types of amounts would crush November daily precipitation records at most locations, and may even challenge all-time records for the month. A 1.5-inch daily precipitation total during November would be an extreme event indeed, and would make the monthly top-10 at almost all Minnesota climate stations. The same is true for three-day totals in excess of two inches. 

Many of Minnesota's heaviest November precipitation events have come during early winter storms, falling as combinations of heavy snow, moderate to heavy rain, ice, and sleet. The Halloween storm of 1991 and the infamous Armistice Day Blizzard of 1940 both produced widespread precipitation totals of over two inches, and therefore show up in the November records of many stations, including Rochester and the Twin Cities.

Although thunderstorms occur occasionally during November, the fast winds aloft and the reduced instability associated with autumn tend to limit their precipitation output. This is one major difference between heavy precipitation during the warm season versus the cold season. Most of Minnesota's heaviest summer rainfall events are caused by prolonged or stalled intense thunderstorm activity.

The largest verified November precipitation events on record for Minnesota are from southeastern parts of the state. Winona holds the state's daily precipitation record for November, with 3.45 inches of rain observed on November 8, 1945. The Winona Dam observers have highest known three-day total for the month as well, with 4.73 inches of precipitation falling as heavy ice, sleet, rain, and snow November 1-3, 1991, during the Halloween Blizzard.

Shown below are heavy November precipitation statistics for Minnesota's five "first-order" climate stations.

November Heavy Precipitation Statistics