An isolated thunderstorm developed along a frontal boundary during the late afternoon in an environment with around 2000 J/kg MLCAPE and deep-layer shear of 40-50 knots. Rotating storms developed with hail, with strong winds also supported by around 1000 J/kg DCAPE.
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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 FSD wrote it up.
An isolated thunderstorm developed along a frontal boundary during the late afternoon in an environment with around 2000 J/kg MLCAPE and deep-layer shear of 40-50 knots. Rotating storms developed with hail, with strong winds also supported by around 1000 J/kg DCAPE.
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 Sioux Falls, SD wrote its last area forecast discussion before the first event at Jul 25, 1:42 PM CST, 1 hour 40 minutes earlier.
Area Forecast Discussion National Weather Service Sioux Falls SD 242 PM CDT Wed Jul 25 2018 .SHORT TERM...(This evening through Thursday) Issued at 242 PM CDT Wed Jul 25 2018 The nose of higher lapse rates aloft was moving through this afternoon with the mid level showers moving east along this nose. Cooler air aloft will settle in fairly quickly behind this feature and surface winds will turn to the north and northwest advecting cooler and drier air southward. Convergence along this boundary is pretty poor with west southwest winds ahead of the cool front. There still might be a brief window when a few thunderstorms develop from about 3 pm to 6 pm. With decent shear and marginal instability there will continue to be a severe threat but it does appear to be on the isolated side. The main threat will be across northwest IA and far southern MN. As the front passes the thunderstorm chances will quickly shift south and clouds will begin to clear. Much of the cloud cover in the area is driven by the higher lapse rates aloft and also diurnally driven cumulus, both of which should be gone by about 3z. Northwest winds will remain about 5 to 10 mph through the night with lows falling to about 53 to 58 degrees. .LONG TERM...(Thursday night through Wednesday) Issued at 242 PM CDT Wed Jul 25 2018 After a cool start to the day northwest winds will increase and likely gust to around 25 mph Thursday afternoon. Model soundings do indicate some moisture at the inversion so expect a cumulus field to develop late in the morning, becoming mostly cloudy over far eastern SD, southwest MN and northwest IA. With the cooler air and cloud cover temperatures will top out in the 70s and likely feel a bit on the cool side with the slightly stronger winds. High pressure will build south on Thursday night and bring lighter winds, clear skies and cooler morning lows. Temperatures on Friday morning will likely be in the 50 to 55 degree range. Friday should be a very pleasant day with light winds, lower humidity and highs in the 70s. Clouds will be on the increase through the day as a wave moves through Wyoming onto the Western High Plains. This will bring an increase in mid and high clouds with a small chance for showers and thunderstorms into south central SD Friday afternoon. Friday night into Saturday the wave will move into the Central Plains with broad mid level warm air advection bringing rain and thunderstorms to areas south of Interstate 90. Instability is pretty weak so not expecting severe weather. And, if everything comes out as expected there may not be a whole lot of thunder either. Once this system passes a large scale trough will settle onto the Plains, bringing cooler conditions and dry weather. By early next week the system will shift a bit east and a gradually warm up to around normal is likely. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1234 PM CDT Wed Jul 25 2018 Few showers have developed along a cold front moving to the southeast this afternoon. After 20Z, could see some thunderstorms develop creating large hail and a strong wind gust or two across northwest Iowa. These storms will shift southeast this evening, leading to clearing skies and northwest winds. Could see cumulus develop during the day tomorrow. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && SHORT TERM...08 LONG TERM...08 AVIATION...BT
Hazardous Weather Outlook National Weather Service Sioux Falls SD 410 AM CDT Wed Jul 25 2018 IAZ001>003-012>014-020>022-031-032-MNZ089-090-NEZ013-014-SDZ067- 070-071-260915- Lyon IA-Osceola-Dickinson-Sioux-O'Brien-Clay IA-Plymouth-Cherokee- Buena Vista-Woodbury-Ida-Nobles-Jackson-Dixon-Dakota-Lincoln SD- Clay SD-Union- 410 AM CDT Wed Jul 25 2018 This Hazardous Weather Outlook is for portions of northwest Iowa, west central Iowa, southwest Minnesota, northeast Nebraska, and southeast South Dakota. .DAY ONE...Today and Tonight Scattered thunderstorms are expected today where some of the stronger storms could become severe later today. Thunderstorm activity in the afternoon will depend on cloud cover. If conditions remain cloudy through the first half of the day, severe storms will be very limited. If sky conditions can break out and allow the atmosphere to destabilize, then golf ball size hail and wind gusts around 70 mph are possible. The severe weather threat is more favored from 3 pm to 9 pm. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Scattered showers and thunderstorms are possible Friday night into Saturday. At this moment, severe weather threat is low. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed tonight. MNZ071-072-080-081-097-098-SDZ056-061-062-065-066-068-069-260915- Lincoln MN-Lyon MN-Murray-Cottonwood-Pipestone-Rock-Moody-McCook- Minnehaha-Hutchinson-Turner-Bon Homme-Yankton- 410 AM CDT Wed Jul 25 2018 This Hazardous Weather Outlook is for portions of southwest Minnesota, east central South Dakota, and southeast South Dakota. .DAY ONE...Today and Tonight Isolated to scattered thunderstorms are possible today. A few of these storms could become strong to severe in the afternoon hours. The primary threats are large hail to half dollar and damaging winds to 70 mph. The severe weather threat is more favored from 3 pm to 9 pm. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Scattered showers and thunderstorms are possible Friday night into Saturday. At this moment, severe weather threat is low. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed tonight. SDZ038>040-050-052>055-057>060-063-064-260915- Beadle-Kingsbury-Brookings-Gregory-Jerauld-Sanborn-Miner-Lake- Brule-Aurora-Davison-Hanson-Charles Mix-Douglas- 410 AM CDT Wed Jul 25 2018 This Hazardous Weather Outlook is for portions of central South Dakota, east central South Dakota, south central South Dakota, and southeast South Dakota. .DAY ONE...Today and Tonight Thunderstorms chances will continue during the day as a cold front moves through. A few storms may be marginally severe with quarter sized hail and wind gusts to 60 mph. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Scattered showers and thunderstorms are possible Friday night into Saturday. At this moment, severe weather threat is low. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed tonight.
The Minneapolis radar (KMPX), 139 km away, was scanning. The volume nearest the first event began at 21:22 UTC.
3 hail, 1 thunderstorm wind. Local standard time, as filed.
Strong winds contributed to a period of wind-driven hail from dime to quarter size. Soybeans were stripped to stubble and leaves ripped off trees. A damage path varied from one to two miles in width where crop losses were nearly total. The duration of the event was around 8 minutes.
Crops destroyed by wind-driven hail.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2018Every state in 2018This day in weather historyWarnings in Minnesota, July 2018
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 2026-09-24. Each event’s entry at NCEI: 773550, 773554, 773551, 773553.