Convection across Nebraska and Kansas in the early afternoon moved into western Iowa on the evening of May 12th. While loss of daytime heating resulted in a weakening of the thunderstorms, dry air across Iowa allowed for gusty winds to continue with the decaying thunderstorms.
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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 DMX wrote it up.
Convection across Nebraska and Kansas in the early afternoon moved into western Iowa on the evening of May 12th. While loss of daytime heating resulted in a weakening of the thunderstorms, dry air across Iowa allowed for gusty winds to continue with the decaying thunderstorms. This included some tree damage reported in parts of northern Iowa.
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 Des Moines, IA wrote its last area forecast discussion before the first event at May 12, 5:38 PM CST, 2 hours 2 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 638 PM CDT Thu May 12 2022 ...Updated for the 00z Aviation Discussion... .UPDATE... Issued at 638 PM CDT Thu May 12 2022 Updated zones for higher winds northwest/west and issued SPS for potential hazardous travel if the gust front accompanied by dust and visibility under 1 mile holds together and enters our far northwest. Otherwise, storms still possible this evening with northwest cluster and the new area in eastern Nebraska. && .DISCUSSION.../Tonight through Thursday/ Issued at 245 PM CDT Thu May 12 2022 Key messaging highlights: * Thunderstorms, possibly severe with damaging wind west this evening, dissipating west to east tonight. Redevelopment possible far southeast into peak heating tomorrow * Return of more seasonal temps and humidities into next week * Chances for showers and storms this weekend, and again starting the middle of next week Our weather can generally be separated into three regimes, tonight into tomorrow, the weekend, and then next week with all including a transition to more seasonal temperatures and humidities. Initially this evening the focus will be on upstream convective trends, which are already underway across NE/KS and ahead of schedule per convection allowing model(CAM) projections. The airmass ahead of this complex currently has some inhibition challenges, but the convection is expected to persist considering the degree of synoptic forcing and realize the 2500-3000 J/kg MLCAPE environment as it advances eastward. The primary threat this far east will certainly be damaging winds, which may extend well beyond the precipitation in outflow, even in decaying convection, with fairly dry soundings resulting in high DCAPEs and 3km delta theta-e. While mid level lapse rates are steep, the lack of deep shear this far east and the high freezing level may decrease the large hail threat to just low end severe limits or less. High LCLs and the lack of adequately strong and favorably oriented 0-3km shear will reduce the QLCS tornado potential as well. The CAMs and extrapolation suggest the convection will reach our western forecast area 7-8pm, and then weaken shortly thereafter and into the night with CIN eventually building with the loss of heating, and possibly fade altogether overnight. There was some question where the front would re-ignite during peak heating tomorrow south and east, but recent guidance trends suggest that better potential may be south and east out of the forecast area due to frontal placement and instability exiting, so precip chances have been reduced. The next precip window will then come into focus this weekend, looking at the track of the short wave now off the Pacific NW. This will follow our current compact PV anomaly with the southern axis of the Manitoba trough bringing through a period of forcing with low instability Saturday Night into Sunday. Looking further into next week, the amplitude decreases and becomes more zonal by Tuesday with most models suggesting lee side cyclogenesis and and associated baroclinic zone developing somewhere to our south, which will combine with weak kinematic forcing aloft farther north for more generally weak convection chances, although the instability is a bit better far south toward the MO border. These chances will persist through the remainder of the period, but this is more weighted toward lower confidence in the model consensus and NBM rather than the potential for extended rainfall. With limited instability next week, severe weather is not anticipated. This zonal flow and gradually sagging heights will also keep our temperature regime much closer to seasonal values, including humidities. This trend looks to persist beyond the valid period into the following weekend as well with most guidance suggesting the lack of any heat or humidity building. && .AVIATION.../For the 00Z TAFS through 00Z Friday evening/ Issued at 638 PM CDT Thu May 12 2022 Lowered cigs and visby west with approaching gust front and dust particularly northwest at FOD which probably has some chance of seeing some impacts. Farther east, little expected at MCW. Winds stronger this evening ahead of boundary with potential again for some lowering cigs with passing convection. /rev && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && UPDATE...REV DISCUSSION...Small AVIATION...REV
Hazardous Weather Outlook National Weather Service Des Moines IA 334 PM CDT Thu May 12 2022 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-132045- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun- Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene- Boone-Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper- Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union- Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne- Appanoose-Davis- 334 PM CDT Thu May 12 2022 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...This afternoon and tonight Heat index values into the mid to upper 90s across much of the area this afternoon. Another round of storms are expected tonight from western into central Iowa. These may be severe with damaging winds the main concern at this time with the highest risk over west and northwest Iowa. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Additional storm chances are possible on Friday and again Saturday night into Sunday. The risk of severe weather is low. .SPOTTER INFORMATION STATEMENT... Spotters may be needed tonight. Dodson
Special Weather Statement National Weather Service Des Moines IA 557 PM CDT Thu May 12 2022 IAZ004-005-015-023-024-033>035-130100- Emmet-Kossuth-Palo Alto-Pocahontas-Humboldt-Sac-Calhoun-Webster- Including the cities of Estherville, Algona, Emmetsburg, Pocahontas, Laurens, Rolfe, Fonda, Gilmore City, Humboldt, Sac City, Lake View, Odebolt, Wall Lake, Schaller, Early, Rockwell City, Manson, Lake City, Pomeroy, and Fort Dodge 557 PM CDT Thu May 12 2022 ...Gusty South Winds Increasing to West Southwest Between 630 PM and 730 PM this Evening... Strong low pressure over Central Nebraska is enhancing south wind gusts to near 40 to 45 mph at times this evening. An area of thunderstorms is entering northwest Iowa with a rather strong gust front, accompanied by a wall of dust. This is moving east northeast and may enter the Pocahontas and Emmet County areas between 630 and 730 pm this evening. Wind speeds may continue over 50 mph with the gust front and visibility may lower to under a mile at times. Persons should be aware of the potential for adverse travel conditions this evening in this area and be prepared for a period of strong winds. The gust front should weaken somewhat as it moves east, but some areas of blowing dust may still occur farther east this evening. Persons traveling over the region should be ready for cross winds this evening; particularly if driving a high profile vehicles as well as potentially low visibility. Please drive carefully. IAZ044>047-057>059-070>072-081-082-092-093-130100- Crawford-Carroll-Greene-Boone-Audubon-Guthrie-Dallas-Cass-Adair- Madison-Adams-Union-Taylor-Ringgold- Including the cities of Denison, Carroll, Jefferson, Boone, Audubon, Exira, Guthrie Center, Panora, Bayard, Casey, Perry, Waukee, Adel, Atlantic, Greenfield, Stuart, Adair, Fontanelle, Winterset, Earlham, Corning, Creston, Bedford, Lenox, New Market, and Mount Ayr 557 PM CDT Thu May 12 2022 ...Gusty South Winds this Evening... Strong low pressure over Central Nebraska is enhancing south wind gusts to near 35 to 40 mph at times this evening. The winds will begin to slow a bit between 7 and 8 pm this evening. Persons traveling over the region should be ready for cross winds this evening; particularly if driving a high profile vehicles. REV
The Sioux Falls radar (KFSD), 164 km away, was scanning. The volume nearest the first event began at 01:36 UTC.
1 thunderstorm wind. Local standard time, as filed.
Medium sized tree branch down in Graettinger. Report via social media.
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, May 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: 1025402.