A derecho moved across northern Iowa, resulting in a swath of wind damage with gusts of 60 to 80 mph reported, along with two tornadoes that occurred along the leading edge of the line of storms. The line of storms developed with an embedded shortwave that rode over a larger upper level ridge.
Every event with a place to put it. Tap one for its entry below.
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 derecho moved across northern Iowa, resulting in a swath of wind damage with gusts of 60 to 80 mph reported, along with two tornadoes that occurred along the leading edge of the line of storms. The line of storms developed with an embedded shortwave that rode over a larger upper level ridge. That ridge allowed for hot and humid conditions across the area with temperatures in the upper 80s to low 90s and dewpoints in the 70s, resulting in heat indicies well over 100. This made for a deeply unstable airmass with over 5000 J/kg of MLCAPE and the line of storms rode the CAPE gradient across northern Iowa overnight. With 30-35 kts of 0-6 km shear, convection was able to maintain strength, and 0-3 km shear near 25 kts orthognal to the line was able to provide just enough of a tornadic set up. The line of storms reach western portions of the area by around 11 pm local time and finally exited east just after 2 am local time. Widespread tree damage and power outages were reported with this line of storms.
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 Jul 28, 5:42 PM CST, 4 hours 10 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Des Moines IA 642 PM CDT Mon Jul 28 2025 ...Updated for the 00z Aviation Discussion... .KEY MESSAGES... - Strong to intense storms with damaging wind gusts racing east- southeastward reaching north central Iowa after 8 or 9pm this evening and exiting before sunrise Tuesday. Confidence highest in damaging wind gusts and highest wind gusts around to 75 mph or a bit higher north of Highway 20 with potential for severe winds of around 60 mph perhaps as far south as portions of Highway 34 over eastern Iowa. - Dangerous combination of heat and humidity over Iowa this afternoon and again over southern Iowa Tuesday. - Numerous storm chances Tuesday evening through Wednesday. Locally heavy rainfall of 3 to 5 inches leading to the potential of flash flooding and renewed river rises exists. Damaging wind gusts and large hail are the main severe hazards. - Turning cooler, less humid with no widespread rain and storm chances late this week. && .DISCUSSION... Issued at 328 PM CDT Mon Jul 28 2025 Main concern this forecast cycle is the round of storms that is forecast to move across South Dakota, southern Minnesota, and into portions of Iowa later this evening into the pre-dawn hours of Tuesday. Damaging wind gusts potentially of 75 mph or a bit higher are the main concern with this setup being detailed shortly below. Morning visible satellite imagery showed the overnight storms and their associated outflow well south of the state, though a few storms did pop several times between Creston, Atlantic and Carroll this morning and early this afternoon. It is just a testament to the juicy airmass given the 700mb temperatures, which KOAX RAOB measured 13.4C at 18z. Overall, temperatures have made a full recovery into the 80s to near 90 degrees and reliable dewpoints are back into the 70s, which is a tad lower than expected yesterday. While heat index values may end up being 5 or so degree lower, messaging of headlines and taking heat safety precautions will remain unchanged. Looking at the synoptic pattern late this afternoon into tonight, there remains the upper level ridge, which is now centered over the lower Mississippi River Valley. Convection is ongoing over North Dakota and is associated with a shortwave trough topping the ridge. The storms that are expected to make it into Iowa this evening may be attempting to develop over western/central South Dakota this afternoon. However, greater development is forecast late this afternoon with storm clusters merging into a propagating mesoscale convective system (MCS). Convective allowing models (CAMs) show a variety of solutions ranging from the MCS staying largely north of the state (low to no Iowa impact) to the MCS moving across northern and sink southeastward across the state (higher impact to Iowa). There is high confidence that storms will move into the region and seems at least over northern Iowa and our service area sometime after 8 or 9pm this evening. These storms will be moving quickly as well as they navigate the top of the warm 700mb temperatures, which makes it uncertain how far south the storms will make it over Iowa. The main hazard will be damaging wind gust that will be over 60 mph and perhaps at or a bit above 75 mph. The highest wind gusts are forecast over norther Iowa, roughly north of Highway 20. In addition, 0-3km wind shear values will have sufficient magnitude for mesovortex generation/embedded circulations with the bowing segments. This potential of leading line tornadoes is highest for segments that move more east vs southeast or south, which would result in the system becoming out of balance. The storms will be trucking and should be exiting our forecast area by 3 or 4am. Finally, as SPC highlighted in a discussion earlier today, "One or more corridors of widespread/significant wind damage are expected, possibly achieving derecho criteria". Of course, there is a range of magnitude of derechos ranging from the criteria based wind gusts of 75 mph up to what many Iowans remember from the August 2020 or Siouxland derechos of spring 2022. At this time, this does not look to be the upper tier, August 2020 type derecho. The potential that this may meet the criteria and definition of a derecho may extend into at least northern Iowa, but recall that whether or not an event is determined to meet the criteria of a derecho is determined after the event in discussions with the Storm Prediction Center. Much of the daytime Tuesday will be rain and storm free in the wake of the nocturnal MCS. A surface boundary will be dropping slowly through the state. Over southern Iowa, another day of very warm and humid conditions will lead to a heat advisory for those areas centered around the afternoon hours. As we move into the evening, the next shortwave trough will be approaching from Nebraska. This feature in conjunction with a weakening low level jet (LLJ) and pulses of low level thermal lift will help to initiate storms. This looks to be at the earliest late afternoon, but more likely sometime in the evening. Further, another MCS may approach from Nebraska sometime late in the evening if not after midnight. There will be plenty of instability and marginal amounts of deep layer shear such that large hail, at least initially in the afternoon or evening, along with damaging wind gusts throughout the evening into the night will be the main severe hazards. Storms will continue into Wednesday with severe weather also possible south of the boundary somewhere over southern Iowa. Damaging wind gusts and hail on Wednesday would be the main concern once again. In addition to the severe weather, flash flooding is also a concern Tuesday night into Wednesday. Low level specific humidity through Tuesday night is forecast to be at the 99th percentile with precipitable water values topping 2 inches along this boundary. Deep warm cloud depths with slow storm motions should lead to storms repeating over the same area. Though as mentioned yesterday, the weaker LLJ may allow the surface boundary to continue to sink southward and thus storms may not repeat over the same areas. Rainfall has ticked upwards with totals of 3 to 5 inches by later Wednesday in the global models and available CAMs. This rainfall will be falling over soils that NASA SPoRT show at the 70th percentile or higher from around Highway 20 southward, east of Highway 71, and into southeast Iowa in the 0-10cm and 10-40cm layers. This could set the stage for rapid onset flooding/flash flooding, particularly in urban areas or those that have had recent rainfall, which was just mentioned by more saturated soils. The National Water Model (NWM) rapid onset flooding forced by the GFS, which lays out the heavy rainfall west to east across Iowa, shows high probabilities over many portions of north central and central Iowa. Further, this rainfall would certainly slow the recession at the very least with renewed river rises quite possible. QPF ensemble hydrographs show that with best estimate rainfall, a few river points in the Iowa and Cedar basins could reach minor or even moderate flood stage by late in the week or the weekend. Examining the NWM high flow magnitude forecast forced by the GFS shows annual exceedance probabilities (AEPs) with a low probability of a high impact event on parts of the Raccoon, the upper Des Moines, Iowa, and Cedar basins. Of course, this can easily change depending on where the rain falls and the magnitude and duration of said rainfall. The boundary finally is pushed south of the state Thursday ushering in cooler, less humid air along with no widespread rain or storm chances through at least Saturday. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 626 PM CDT Mon Jul 28 2025 Storms continue to be the main concern for aviation this evening, with only minor changes to the general line of thinking from the 18z issuance. Small timing adjustments have been made for those sites potentially impacted by storms (KFOD, KMCW, KALO, and KDSM), although exact timing will rely on how ongoing storms over Nebraska and South Dakota evolve through the next few hours. Have also added increased wind gusts to the PROB30 groups at KFOD and KMCW, which appear to be the most likely sites to see increased winds at these sites. Both of these forecasts include gusts of 43kts but gusts as high as 50 to 60 kts are certainly possible with storms this evening. That said, the eastern and southeastern extent of storms and associated impacts remains in question, so maintained the PROB30 groups at KALO and KDSM where confidence is lower. After storms pass through overnight, MVFR ceilings look to move in for a brief period tomorrow morning, mainly in northern Iowa. Don't anticipate this will be long-lived, but did include BKN MVFR ceilings at KFOD and KMCW where confidence is highest. Additional showers and storms are expected tomorrow evening across central Iowa, mainly at the end of this TAF period and beyond. && .DMX WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM CDT this evening for IAZ004>007-016- 017-025>028-037>039-050. Extreme Heat Warning until 8 PM CDT this evening for IAZ015- 023-024-033>036-044>049-057>062-070>075-081>086-092>097. Heat Advisory from noon to 8 PM CDT Tuesday for IAZ070>075- 081>086-092>097. && DISCUSSION...Ansorge AVIATION...Dodson
Hazardous Weather Outlook National Weather Service Des Moines IA 1011 PM CDT Mon Jul 28 2025 IAZ004>007-015>017-023>028-033>039-044>050-057>062-300315- 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- 1011 PM CDT Mon Jul 28 2025 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Tonight There is a Moderate Risk (Level 4 of 5) of severe weather over much of the area. The primary threat is damaging wind gusts with these storms. Heavy rainfall is also possible. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Additional thunderstorms are forecast from late Tuesday afternoon through Wednesday night. The severe thunderstorm and flash flood threat for later Tuesday and Wednesday will be evaluated in the coming days. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed tonight. IAZ070>075-081>086-092>097-300315- Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas- Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis- 1011 PM CDT Mon Jul 28 2025 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Tonight Tonight there is a low risk for severe thunderstorms central and south-central Iowa. The primary threat is damaging wind gusts with these storms. Heavy rainfall is also possible. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday A Heat Advisory is effect on Tuesday afternoon into Tuesday evening. Additional thunderstorms are forecast from late Tuesday afternoon through Wednesday night. The severe thunderstorm and flash flood threat for later Tuesday and Wednesday will be evaluated in the coming days. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed tonight.
The Sioux Falls radar (KFSD), 155 km away, was scanning. The volume nearest the first event began at 03:54 UTC.
20 thunderstorm wind, 2 tornado. Local standard time, as filed.
Personal weather station gust to 62 mph. Widespread tree damage and minor sheet metal damage through the town of Ruthven just south of this station.
Personal weather station gust to 63 mph.
Personal weather station gust to 62 mph.
Personal weather station gust to 72 mph.
Report of 80 mph wind gust.
Personal weather station gust to 64 mph.
A 75 mph wind gust reported by Algona Police.
Trees and powerlines down around Fort Dodge. Delayed report relayed by broadcast media. Time estimated by radar.
Personal weather station gust to 58 mph.
Satellite imagery revealed a track in agricultural fields. No damage indicators were impacted, resulting in the EF unknown rating.
Emergency manager relayed trees down in Garner, some roads blocked.
Emergency manager reported trees down in city of Ventura and power out for part of Clear Lake.
Personal Weather Station gust to 64 mph.
Large grain bins destroyed in Ventura. Delayed report, time estimated from radar. Relayed via social media.
Broadcast media shared drone imagery of a track developing just east of the I-35 and Highway 18 interchange. The tornado primarily tracked through cropland, but did result in tree damage early in the track for an EF0 rating.
Personal Weather Station gust to 59 mph.
Several tree branches down blocking roads in town. Time estimated by radar.
Personal weather station gust to 80 mph.
Gust to 78 mph at Waterloo ASOS.
Several reports across Waterloo of trees on utility lines and transformers. Power is out in various locations around Waterloo. Time estimated by radar and ASOS recorded gust.
Personal weather station gust to 58.
Personal weather station gust to 63 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2025Every state in 2025This day in weather historyThe tornado archive for Iowa, 2025Warnings in Iowa, July 2025
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: 1290277, 1290278, 1290279, 1290280, 1290281, 1290282, 1290283, 1290284, 1290285, 1290275, 1290286, 1290287, 1290288, 1290289, 1290276, 1290291, 1290292, 1290293, 1290296, 1290295, 1290297, 1290298.