With the approach of a strong mid-level wave, a cluster of multicellular storms evolved within a weakly unstable and weakly-sheared environment. A fair amount of dry air at lower levels made for 600 J/kg or more of DCAPE, with storms producing some spotty significant wind damage along a track from near Paullina to around Primghar.
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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.
With the approach of a strong mid-level wave, a cluster of multicellular storms evolved within a weakly unstable and weakly-sheared environment. A fair amount of dry air at lower levels made for 600 J/kg or more of DCAPE, with storms producing some spotty significant wind damage along a track from near Paullina to around Primghar.
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 Aug 27, 12:56 PM CST, 3 hours 22 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 156 PM CDT Sat Aug 27 2022 .SHORT TERM...(This Evening through Sunday) Issued at 150 PM CDT Sat Aug 27 2022 KEY MESSAGES: 1. Convection risks linger this afternoon, low end severe risks. 2. Much warmer Sunday, with severe convection possible late aftn. 3. An extended period of warm and dry weather through next week. THIS AFTERNOON: Mid-lvl shortwave evident across eastern Nebraska on both satellite and radar data this afternoon. Scattered high based showers and thunderstorms will persist across portions of eastern SODAK this afternoon, with more focus turning towards eastern Nebraska and western Iowa. Temperatures continue to slowly rise into the middle 80s, with a narrow wedge of 70+ dew points along the eastern periphery of the CWA. However, fairly widespread thick mid- lvl clouds continue to spread eastward, which may slow down the potential development in NW Iowa after 3pm. Eventually though, strong DPVA will arrive and should kick off scattered thunderstorms in an area of enhanced low-lvl lapse rates. The greatest severe weather risk will be confined to an area along and east of Highway 60, where MLCAPE between 800-1200 J/KG may be possible and less inhibition is expected. Effective shear remains on the weaker side, with most of the shear towards the upper portions of the soundings. Threats with storms are likely more focused towards a few strong wind gusts given 600+ J/KG DCAPE, hail may tend to smaller side given the high freezing levels and weaker shear. The heavy rain risks have likely shifted further southeast into Iowa this evening, but a quick half inch to inch of rain could be possible in a thunderstorm. TONIGHT: Convection slides east of the CWA fairly quickly this evening, leaving clearing skies into Sunday morning. Have lowered temperatures slightly further west, though winds will be quite mixy through the night. Patchy valley fog could be possible. SUNDAY: A stronger mid-lvl trough dips into the Northern Plains on Sunday, pushing a surface cold front eastward through the day. Ahead of this boundary, temperatures will climb well into the 80s and even 90s in some areas south of Interstate 90s. Winds are also expected to be quite gusty, and have nudged towards the 90th percentile of the NBM ahead of the boundary. Low- lvl moisture advection in addition to evapotranspiration effects will push surface dew points into the lower 70s in portions of SW Minnesota into NW Iowa. This will lead to moderate to high instability (3000-4000 J/KG) building along and east of I-29 in the afternoon. Considerable inhibition will prevent convection from forming for much of the afternoon, but as deeper synoptic lift intersects the surface front after 4pm, convection should develop very quickly. Initial storms may form over far NE South Dakota, then begin to form southward along the advancing front into SW Minnesota by 5pm. There is much more uncertainty on just how far south convection may form along the boundary into Iowa and Nebraska, as the greatest DPVA will be shifting northeast away from the area and surface convergence along the front will be weaker in these areas. It is possible current slight risk could expand further south if CAMS indicate more development. Given high degree of instability and slight increase in shear, a few supercell and multicell clusters may form with very large hail and strong wind surges. The good news is that unless the front slows, the overall risk to the CWA may only be 1-3 hours. .LONG TERM...(Sunday Night through Saturday) Issued at 150 PM CDT Sat Aug 27 2022 MONDAY-FRIDAY: A brief cooldown is anticipate to start the new work week as low-lvl cold advection drops temperatures into the 70s and lower 80s. That cool down will be brief as the synoptic pattern suggests an extended period of dry and warmer than normal temperatures. Mid-lvl heights begin to rise through the week, and other than a low potential for a small weakness in the ridge to pass through Thursday, precipitation won't be more than sprinkles for most of the Northern Plains. The return of warmer southwesterly low- lvl flow by Wednesday will trigger an increase in high temperatures, and have favored the slightly warmer ECMWF/GFS over that of the NBM in the extended. In fact, the multi-run trend of the ECMWF ensemble continues to increase the potential highs later in the week. The means highs likely back above normal into next weekend. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1213 PM CDT Sat Aug 27 2022 Mid-lvl energy moving through will continue to produce widely scattered showers and thunderstorms into the afternoon. However VFR conditions will continue in most areas. A more concentrated area of showers and thunderstorms moves east out of Nebraska by mid-afternoon, leading to greater probabilities of lowering ceilings and visibility in NW Iowa and southern Minnesota into early evening. Ceilings may remain at VFR levels into the evening with this activity, though very brief visibility restrictions may be possible. VFR conditions continue into Sunday morning as winds remain breezy. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && SHORT TERM...Dux LONG TERM...Dux AVIATION...Dux
Hazardous Weather Outlook National Weather Service Sioux Falls SD 452 AM CDT Sat Aug 27 2022 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-281000- Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee- Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson- Pipestone-Rock- 452 AM CDT Sat Aug 27 2022 This Hazardous Weather Outlook is for northwest Iowa, west central Iowa and southwest Minnesota. .DAY ONE...Today and tonight. Isolated light showers are possible through the morning hours today. Chance for showers and storms, some of which could be strong to severe, increase later this afternoon and evening. While widespread severe weather is not expected, large hail up to the size of quarters and damaging winds to 60 mph are possible with the strongest storms. Along with the severe weather threat, locally heavy rainfall is possible. Amounts are most likely to span between a quarter to three quarters of an inch but locally higher amounts are possible. Portions of northwest Iowa have the highest potential for locally heavy rainfall. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Another round of strong to severe storms is possible on Sunday. If storms are able to develop, large hail and damaging winds will be the main hazards to be wary of. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. NEZ013-014-SDZ038>040-050-052>071-281000- Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory-Jerauld-Sanborn- Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-Minnehaha- Charles Mix-Douglas-Hutchinson-Turner-Lincoln-Bon Homme-Yankton-Clay- Union- 452 AM CDT Sat Aug 27 2022 This Hazardous Weather Outlook is for northeast Nebraska, central South Dakota, east central South Dakota, south central South Dakota and southeast South Dakota. .DAY ONE...Today and tonight. Isolated showers and weak storms are possible throughout the day today. Severe weather is not expected. .DAYS TWO THROUGH SEVEN...Sunday through Friday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The Sioux Falls radar (KFSD), 112 km away, was scanning. The volume nearest the first event began at 22:18 UTC.
7 thunderstorm wind. Local standard time, as filed.
A roof was removed from part of a farm outbuilding by thunderstorm winds.
Machine sheds and cattle buildings were severely damaged by thunderstorm winds.
A farm outbuilding was destroyed by thunderstorm winds. Crop damage is an estimate from insured losses. Information provided by the United States Department of Agriculture.
A thunderstorm wind gust of 66 mph was measured by Automated Surface Observing System site KSPW 4 miles west-northwest of Spencer.
A large, but decaying tree, was downed by thunderstorm winds.
Thunderstorm winds downed a large 100-year-old tree, and removed gutters from a house.
Tree branches were downed by thunderstorm wind gusts.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2022Every state in 2022This day in weather historyWarnings in Iowa, August 2022
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: 1054601, 1054595, 1054598, 1054593, 1054600, 1054597, 1054594.