A strong low level jet surging into the region, paired with increasing warm air and moisture advection into the morning hours of May 24th, led to the development of a line of showers and storms (QLCS) in Nebraska, which then swept across Iowa. MUCAPE values around 2000J/kg ahead of this line allowed for these storms to become severe within the QLCS as it rapidly tracked eastward across Iowa…
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 strong low level jet surging into the region, paired with increasing warm air and moisture advection into the morning hours of May 24th, led to the development of a line of showers and storms (QLCS) in Nebraska, which then swept across Iowa. MUCAPE values around 2000J/kg ahead of this line allowed for these storms to become severe within the QLCS as it rapidly tracked eastward across Iowa through the morning. Severe hail occurred with these storms, with values generally between 1-1.75 inches, though hail up to 2.5-2.75 inches was reported in Wayne county. Outside of the hail, severe winds were the primary hazard, with values reported generally between 58-75 mph. Widespread damage was reported due to the winds, with the majority of this damage being snapped trees/branches and power poles, some falling onto structures, as well as blown over semis. Outside of the hail and winds, a handful of tornadoes also occurred (please refer to the separate entry for those details).
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 23, 11:43 PM CST, 1 hour 22 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Des Moines IA 1243 AM CDT Fri May 24 2024 ...Updated for the 06z Aviation Discussion... .KEY MESSAGES... - A potentially large MCS is expected to move through Iowa tonight. - Severe weather is possible, with the primary risks being damaging winds and large hail, but tornadoes are possible as well, especially in the southern end of the QLCS/squall line. - The Storm Prediction Center has a Level 3 Enhanced Risk western counties, and a level 2 slight risk through central Iowa, lowering to a marginal level 1 risk for eastern counties. - Heavy rainfall could occur tonight, and with that, flash flooding could be a concern in isolated areas. && .DISCUSSION... Issued at 218 PM CDT Thu May 23 2024 /Tonight through Saturday/ A beautiful day is found across Iowa today, with seasonal temperatures in the mid to upper 70s, low dewpoints in the upper 40s to lower 50s, and winds of 10 to 20 mph. This pleasant air is found to the north of a developing warm front, as there is widespread 60 - 70 degree dewpoints found throughout locations to the south in Kansas through Missouri and the lower Ohio Valley. In a typical MCS set up, the advection of this warm unstable air will force strong to severe storms near and to the north of the developing warm front tonight. The upper wave triggering storms in along this boundary is found well to the west, but should help initiate storms in eastern Nebraska by mid to late evening. A deeply sheared atmosphere will be found over eastern NE through Iowa tonight, allowing for organized storms. These will most likely form into a QLCS over eastern Nebraska and race eastward, generally north of Interstate 80, as there is a notable EML/capping inversion found to the south. That southern edge of the convection will be important overnight, as this both could keep the event from occurring in southern Iowa, and also allow the southern end of the line of storms to retain a favorable profile for supercells, including tornadoes well into the night, possibly through daybreak. Thus, the chance for storms is somewhat lower south of Highway 30 late tonight, but the overall chance for severe weather occurring with them is higher than to the north where the depth of a stable boundary layer approaches 4000 ft. In a QLCS mode, +30kts of 0-1km shear will allow for possible spin up tornadoes along the leading edge, generally in areas that have dewpoint values over 55 degrees, keeping the boundary layer somewhat neutrally buoyant, vs confidently stable (highway 20). QPF tonight will be generally under 1 inch in most of the CWA, due to the fast moving storms, with low training potential. There certainly could be a warm advection wing of storms once a mature QLCS develops, but those leading cells should lift northeast rather quickly without significant QPF. This progressive scenario suggests that no flood watch be issued, despite areas that are sensitive to heavy rainfall, especially west and east CWA counties. We'll watch those areas carefully tonight for any localized flooding threats. Friday, a cold front will sweep through during the morning hours, with any new storm development possibly only affecting eastern counties towards early afternoon, followed by a dry night Friday night and Saturday. A "windows open" night is expected Friday night, with lows in the mid to upper 40s. Saturday, highs in the 70s are expected before another strong wave approaches the region Saturday night and Sunday. Following section issued at 335 AM... .Long Term /Saturday Night through Wednesday/... Confidence: Medium As we approach Saturday night, another area of low pressure will track into the Central Plains. The bulk of the energy is still forecast by the medium range models to be just southeast of Iowa, though the Euro does bring some slightly more unstable air into the southeast/south by 12z Sunday. Though severe storms are not expected, there may be a few stronger storms in far southeast and southern Iowa. Rainfall may be the bigger issue, with another half inch to inch across the south half of the state. Certainly not needed at this time. Lows Saturday night will be in the 50s to around 60 with highs Sunday in the 60s to lower 70s. As we round out the weekend, there is lower confidence heading into Monday as operational model runs diverge. The current EPS is more supportive of the operation GFS with the light rain lingering Sunday night into Monday over the region. This will likely keep the region cooler and somewhat cloudy/wet with highs in the 60s to lower 70s again. From Tuesday through Wednesday night, a break from the wet weather is expected. Highs should gradually warm back to the mid to upper 70s. By Thursday some scattered showers and storms are possible with cooler highs in the lower to mid 70s. We may need to make some temperature adjustments at that time. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1240 AM CDT Fri May 24 2024 Showers and thunderstorms are expected overnight into Friday morning with MVFR to locally IFR conditions in and around thunderstorms. Locally strong winds are also expected with the storms as well with fast movement to the east. The convection is expected to continue ahead of front in the morning with the precipitation ending by afternoon as a front pushes through the state. Strong west winds are expected on Friday afternoon in the wake of the front before rapidly decoupling on Friday evening becoming light by the end of the period. && .HYDROLOGY... Issued at 218 PM CDT Thu May 23 2024 Both short-term (flash flooding) and longer-term (river flooding) hydro concerns will continue over the next few days due to the combination of current hydrologic conditions and QPF. In terms of flash flooding concerns, we may see some isolated issues tonight into Friday morning with the thunderstorm activity. With the storms expected to be rather progressive the rainfall is not expected to be too heavy. Thus based on present information a flood watch should not be needed. That being said, SAC-SMA soil saturation values remain in the 40 to 60% range across the eastern CWA roughly bounded by I-80, US 218, US 20 and I-35. In the western CWA they are also elevated in the Audubon-Guthrie-Jefferson County area. When soil saturation values exceed 50% the flash flood concern increases markedly. Thus, those areas will be the most likely areas to watch tonight into Friday morning. Fortunately in those areas the smaller streams have begun receding or have receded already. River flooding is more of a concern especially regarding how the forecast rainfall will affect already high river levels. River flooding continues or is forecast across portions of the Cedar, Iowa, Skunk, Des Moines and Raccoon River basins as well as their tributaries. Moderate flooding is occurring along portions of the Iowa River as well as Black Hawk Creek in northeast. The latest river forecasts updated this morning take into account 24 hrs of QPF ending Friday morning. Additional QPF is in the forecast beyond Friday morning. Looking beyond 24 hrs using our QPF ensemble hydrographs and Hydrologic Ensemble Forecast System (HEFS), the most likely scenario in most places is that the rain over the next several days will slow the fall of area rivers and possibly result in secondary crests. Those secondary crests would be lower than the levels we are presently seeing except for portions of the Iowa River and the South Skunk River across the eastern CWA where a long, broad crest is expected. That is due mainly to the timing of crests working their way down both rivers combined with runoff from future rainfall. Along both rivers the broad crests may extend well into the Memorial Day weekend before the river levels begin falling. In the Des Moines area as well as the Eddyville/Ottumwa areas, river levels on the Des Moines River are affected heavily by the Saylorville and Lake Red Rock reservoirs operated by the U.S. Army Corps of Engineers (USACE). Coordination with the USACE indicates they plan to adjust (minimize) outflows from the reservoirs to try to minimize flooding issues downstream. Having said that, minimizing outflows will result in building pool elevations more quickly on the lakes. As a result, we will see decent rises on both Saylorville and Lake Red Rock again. The rises on Saylorville will likely be similar to what we saw in the last event but they will be higher on Lake Red Rock. In the last event Lake Red Rock crested around 747 ft but with this event it is expected to go to around 754-755 ft. Those forecasts may change going forward due to the actual rainfall amounts. If the rainfall comes in higher than forecast then we would see long, broad crests at more locations in our CWA and higher secondary crests. We will continue monitoring. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && DISCUSSION...REV AVIATION...Cogil HYDROLOGY...Zogg
Hazardous Weather Outlook National Weather Service Des Moines IA 150 AM CDT Fri May 24 2024 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-250700- 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- 150 AM CDT Fri May 24 2024 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and Tonight Widespread thunderstorm will continue over the region early today. An enhanced risk of severe storms continues to central Iowa early this morning with a surrounding slight risk across eastern Iowa. This afternoon the focus for some severe storms will shift into eastern Iowa. Large hail, damaging thunderstorm winds, and a few tornadoes are possible. Locally heavy rainfall from a few of the storms may lead to localized renewed ponding of water or local runoff and a small risk of flash flooding early today. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Other chances for storms are in the forecast for Saturday night into Sunday and Monday. There is a small risk of strong to severe storms Saturday night into Sunday morning over the south. Some lingering showers and thunderstorms will be possible into Monday and again by late Wednesday into Thursday. .SPOTTER INFORMATION STATEMENT... Spotters may be needed briefly early this morning and possibly again later Saturday night into early Sunday. REV
Special Weather Statement
National Weather Service Des Moines IA
159 AM CDT Fri May 24 2024
IAZ023-034-035-240730-
Calhoun IA-Webster IA-Pocahontas IA-
159 AM CDT Fri May 24 2024
...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL WEBSTER...
SOUTHEASTERN POCAHONTAS AND CALHOUN COUNTIES THROUGH 230 AM CDT...
At 158 AM CDT, Doppler radar was tracking a strong thunderstorm near
Lake City, or 6 miles south of Rockwell City, moving north at 35 mph.
HAZARD...Wind gusts up to 40 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Rockwell City, Lake City, Manson, South Twin Lake, North Twin Lake,
Pomeroy, Lohrville, Twin Lakes, Barnum, Knierim, Rinard, Jolley, Twin
Lakes State Park, and Rockwell City Municipal Airport.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4265 9471 4255 9434 4221 9455 4221 9467
4224 9478
TIME...MOT...LOC 0658Z 196DEG 32KT 4230 9465
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH
JimenezThe Des Moines radar (KDMX), 106 km away, was scanning. The volume nearest the first event began at 07:04 UTC.
51 thunderstorm wind, 17 hail. Local standard time, as filed.
Spotter submitted photo of quarter sized hail in Rockwell City. Time of occurrence was estimated from radar.
Delayed report of pea to nickel sized hail in Elkhart.
Social media report between Cambridge and Nevada.
Time of occurrence estimated from radar.
No comments in the local storm report with this event.
Time of occurrence estimated from radar.
No comments included with this local storm report.
MPING report from the public.
No additional comments to include.
Delayed report with picture of at least baseball sized hail on the west side of Humeston.
Delayed report from media of two inch hail near Humeston.
Relayed from broadcast media of a social media report of tennis ball size hail near Humeston.
Social media report of hail, in which the size was estimated.
Delayed report of hail up to golf ball size from the Derby Fire Department. The time of occurrence was estimated from radar.
Wind gusts of 70 to 75 mph, along with dime-sized hail.
Delayed report of a tree down on a house and damage to farm buildings. Time of occurrence was estimated from radar.
Semi blown over and trees down near Rockwell City.
Trees and power lines down as reported from emergency manager.
Delayed report of widespread tree damage. Time of occurrence was estimated from radar.
Peak wind reported at Perry Airport.
Delayed report of 51 knot peak wind gust at the Estherville airport.
Several larger trees down in Perry, along with 3500 customers without power.
Delayed report on social media of trees down on the east side of Winterset. Time of occurrence estimated from radar.
Large tree down on a car in St. Charles. Time of occurrence estimated from radar.
Wind gust report by a trained spotter.
Personal weather station recorded a wind gust of 69.5 mph.
Delayed social media picture of power poles down near Boxholm. Time of occurrence estimated from radar.
Large branch and power line down in the street.
Submitted picture of half dollar sized hail in Elk Run Heights.
Delayed report of a large tree down south of Indianola. Time of occurrence was estimated from radar.
MPING report of penny sized hail.
Submitted photo of quarter sized hail near Sandyville. Time of occurrence was estimated from radar.
Delayed social media report of leaning power poles east of Humboldt on Hwy 3. Time of occurrence estimated by radar.
Delayed report of a tree down on a house. Time of occurrence estimated from radar.
Delayed report on social media of a picture of large tree branches down in Johnston. Time of occurrence estimated from radar.
One inch hail reported west of Lovilia, which was relayed from broadcast media. Time and location were estimated from radar.
Personal weather station wind gust report.
Social media report of tree uprooted from the ground.
Emergency manager reported power lines down. Highway 92 blocked with a large tree on the highway. Time and location of occurrence estimated from radar.
Delayed social media report of a large tree down on the south side of Ames. Time of occurrence estimated by radar.
Social media report of a large tree snapped on S Duff on the south edge of town. Time and location estimated from radar.
Estimated 70 to 80 wind gusts reported from Sheriff Deputy.
No comments included in this report.
Delayed social media report of a large tree down in Pleasantville. Time of occurrence estimated by radar.
Delayed report of semis tipped over on I-35 near mile marker 139, along with power line damage. Time of occurrence estimated from radar.
Quarter size hail in Readlyn.
Large tree branches down and power outages. Simi crashes along I-35.
Ping pong hail briefly fell, followed by winds. Time of occurrence was estimated from radar.
Personal weather station wind gust report.
Powerlines and trees down, along with flipped campers. Time of occurrence estimated with radar.
Picture of large tree down on house in Pershing. Time of occurrence estimated with radar.
Storm chaser measured 84 mph wind gust with a hand-held anemometer. Also observed power flashes and trees down. Time of occurrence was estimated from radar.
Peak wind gust reported at Iowa Falls Airport.
Peak wind gust reported at the Newton Airport.
Emergency manager reported overturned semis on Highway 20. Time of occurrence estimated from radar.
Delayed report of damage to a large farm building just east of Belmond with debris strewn into the field. Time of occurrence estimated from radar.
Peak wind gust reported at the Pella Airport.
Delayed report of large trees down and a silo destroyed south of Pella. Time of occurrence estimated by radar.
Delayed social media report of a large tree down near Otley. Time of occurrence estimated by radar.
Tree fell on garage in Pella. Time of occurrence estimated with radar.
Picture of large branches that came down in Pella.
Inch and a quarter sized hail, along with 1-2 foot diameter trees toppled on garages and homes.
Social media report of tree that is partially down.
Tree and utility damage near Wellsburg. Time of occurrence estimated from radar.
Peak wind gust reported at the Mason City Airport.
Peak wind gust reported at the Oskaloosa Airport.
Delayed report of estimated 70 mph winds and large branches down. Time of occurrence was estimated from radar.
Delayed report from emergency management of wind damage to trees and buildings. Time of occurrence estimated from radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2024Every state in 2024This day in weather historyWarnings in Iowa, May 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: 1181790, 1181791, 1181792, 1181793, 1181794, 1181796, 1181795, 1181797, 1184315, 1181801, 1184305, 1184306, 1184307, 1184308, 1184317, 1184968, 1184349, 1184970, 1184973, 1184318, 1184345, 1184351, 1184976, 1184978, 1184342, 1184343, 1184981, 1184982, 1184309, 1184984, 1184310, 1184312, 1184985, 1184986, 1184987, 1184311, 1184319, 1184989, 1184990, 1184988, and more.