A severe thunderstorm moved across Worth County on the evening of August 5th producing 3 tornadoes. The tornadoes remained in rural cropland and were all rated as EFUs.
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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.
A severe thunderstorm moved across Worth County on the evening of August 5th producing 3 tornadoes. The tornadoes remained in rural cropland and were all rated as EFUs.
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 Aug 5, 5:49 PM CST, 1 hour 18 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Des Moines IA 649 PM CDT Mon Aug 5 2024 ...Updated for the 00z Aviation Discussion... .KEY MESSAGES... - Shower/storm chances north this afternoon and evening. A few storms could be strong to severe with large hail and damaging winds. - Mainly quiet through the rest of the week with below average temperatures and humidity. && .DISCUSSION... Issued at 221 PM CDT Mon Aug 5 2024 As of 19z GOES water vapor imagery shows quasi-zonal to northwesterly flow aloft over the region, on the northern periphery of a broad upper high stretching from the Four Corners to the southern Plains. An embedded shortwave perturbation was noted over the eastern Dakotas. Sfc analysis places a low pressure center in southeast SD, with a nearly stationary warm frontal boundary stretching east across northern IA and a cold front further west across central NE. Showers and storms remain possible across our northern counties this afternoon into the evening. Deep moisture pooling near and just behind the aforementioned warm front has pushed MLCAPE values to near or above 2000 J/kg, although capping between 850-700mb has prevented any CI in our cwa thus far. Model guidance today has mostly continued the slight northerly trend with convective probabilities, preferring to develop the deepest convection near the surface low and track southeast along the edge of the warmer mid-level air from southern MN through northeast IA. Probs look to increase in our area if convection grows upscale along the front and develops an organized cold pool. The shear/instability parameter space is favorable for any storm to potentially become severe, capable of large hail and damaging winds, in addition to heavy downpours. The remainder of the forecast is dominated by below normal temperatures/humidity and only minor chances for precipitation. Cold front clears the area tonight with widespread cloud cover and cooler north winds in its wake. This will pull highs for Tuesday back into the 70s. MET/MAV guidance both suggest our northern areas may struggle to get out of the 60s, but opted not to go that cool with the MaxT forecast given that stratus cover begins to erode by mid to late afternoon. Models bring a deep upper low due south through central Canada Wednesday into Wednesday night. This will push a reinforcing cold front through the state along with chances for light showers and a few rumbles of thunder as synoptic forcing mechanisms work to squeeze out the limited available moisture. High confidence in below normal temps/humidity lasting through the rest of the week and into the weekend as an area of Canadian high pressure settles into the region. NAEFS advertises 850mb temps running near or below the 10th percentile. NBM forecast highs in the 70s most days with some low 80s sprinkled in as well as lows falling into the 50s a few overnights. Lows in the upper 40s cannot be ruled out in the typical favored cool spots of western and northern Iowa this weekend. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 648 PM CDT Mon Aug 5 2024 VFR conditions were in place across the forecast area at 00z with nothing beyond spotty mid clouds. Thunderstorms over southern MN are expected to drop ESE into northern IA later this evening however, possibly affecting KALO but more likely KMCW 01-03z. After any showers and storms exit later this evening, the potential for MVFR/IFR stratus will increase as a cold front moves through during the early morning hours. These MVFR/IFR ceilings may persist through at least mid afternoon in many locations with minor NW wind gusts. && .DMX WATCHES/WARNINGS/ADVISORIES...None. && DISCUSSION...Martin AVIATION...Small
Hazardous Weather Outlook National Weather Service Des Moines IA 328 AM CDT Mon Aug 5 2024 IAZ023-033>035-044>049-057>062-070>075-081>086-092>097-060830- Pocahontas-Sac-Calhoun-Webster-Crawford-Carroll-Greene-Boone- Story-Marshall-Audubon-Guthrie-Dallas-Polk-Jasper-Poweshiek-Cass- Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas- Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis- 328 AM CDT Mon Aug 5 2024 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Today will be very warm and humid with afternoon heat index values in the upper 90s to low 100s. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Very low chances for storms are in the forecast at times through Sunday though most locations will remain dry. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. IAZ004>007-015>017-024>028-036>039-050-060830- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- Humboldt-Wright-Franklin-Butler-Bremer-Hamilton-Hardin-Grundy- Black Hawk-Tama- 328 AM CDT Mon Aug 5 2024 This Hazardous Weather Outlook is for portions of north central Iowa. .DAY ONE...Today and tonight Scattered storms are possible this afternoon and tonight. The main severe weather threats are damaging winds and large hail though a tornado is possible. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Very low chances for storms are in the forecast at times through Sunday though most locations will remain dry. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed north this afternoon and tonight.
The Minneapolis radar (KMPX), 152 km away, was scanning. The volume nearest the first event began at 01:05 UTC.
3 tornado. Local standard time, as filed.
A brief tornado observed by spotters with track found in high resolution satellite imagery. The tornado remained in rural cropland with no impacts to damage indicators, hence the EFU rating.
A brief tornado observed by spotters with track found in high resolution satellite imagery. The tornado remained in rural cropland with no impacts to damage indicators, hence the EFU rating.
A brief tornado observed by spotters with track found in high resolution satellite imagery. This tornado had a looping track with the actual path length of nearly 1.6 miles instead of the 0.84 straight line distance provided by Storm Data. The tornado remained in rural cropland with no impacts to damage indicators, hence the EFU rating.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2024Every state in 2024This day in weather historyThe tornado archive for Iowa, 2024Warnings in Iowa, August 2024
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: 1191467, 1191470, 1191471.