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September 7, 2021 - An Early Morning Late Season Large Hail Event in Northeast Wisconsin


During the early to mid-morning hours of September 7, 2021, two separate squall lines developed over parts of northcentral and northeast Wisconsin. The storms impacted the morning rush hour as they raced east at speeds of 50-60 mph. The first squall line developed shortly after midnight on September 7 and impacted areas north of Green Bay and the Fox Valley. These storms knocked trees and powerlines down across the northern portion of Door County between 6:00 and 6:30 am CDT.  A second and more intense squall line (and a few supercells) developed rapidly, shortly after the first, producing swaths of large hail across east-central Wisconsin and the I-41 corridor between about 8 am and 11 am CDT.  Severe hail ranging from 1 to 4+ inches in diameter damaged some vehicles and roofs of homes from New London and Hortonville, east across the I-41 corridor near Appleton, to southern Brown County (see map below for location of hail and wind reports). The largest measured hail stone reported was at least 4.5 inches in diameter (preliminary) that fell about 5 miles NNE of Appleton! This was the third largest hailstone ever recorded in Wisconsin (see below)!


Here is a list of some of the largest hail stones ever recorded in Wisconsin:


1.  5.7 inch diameter - Wausau (Marathon County) -  May 22, 1921 

2.  5.5 inch diameter - Port Edwards (Wood County) - June 7, 2007

3.  4.5 inch diameter - Oakdale (Monroe County) - June 1, 2000

     Merrill (Lincoln County) - July 16, 1997

     St Croix County - June 19, 1988

     5 NNE Appleton (Outagamie County) - September 7, 2021


The 4.5 inch diameter hailstone north of Appleton on September 7, 2021 would be the largest hail stone to fall so late in the season (since 1950)!

The previous latest date for hail of 4 inches or greater was August 14, 2000.


See below for more information...






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