Waterspouts were observed over southern Lake Michigan as cooler air moved over southern Lake Michigan causing instability and showers.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LOT wrote it up.
Waterspouts were observed over southern Lake Michigan as cooler air moved over southern Lake Michigan causing instability and showers.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Chicago, IL wrote its last area forecast discussion before the first event at Aug 24, 9:30 AM CST, 1 hour earlier.
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</html>The Chicago radar (KLOT), 61 km away, was scanning. The volume nearest the first event began at 16:29 UTC.
2 waterspout. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Lake Michigan in 2017Every state in 2017This day in weather history
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 721122, 721121.