Generally speaking, a bit of everything occurred during an overnight/early morning severe mesoscale convective system that rolled across Iowa. The predominant weather revolved around damaging winds and heavy rainfall, though a few instances of severe hail and low end tornadoes were experienced as well.
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.
Generally speaking, a bit of everything occurred during an overnight/early morning severe mesoscale convective system that rolled across Iowa. The predominant weather revolved around damaging winds and heavy rainfall, though a few instances of severe hail and low end tornadoes were experienced as well. Among the reports, numerous trees were downed, buildings damaged or destroyed from straight line winds or one of the weak tornadoes, and numerous instances of 2 to 4 plus inches of heavy rainfall.
On the setup side of the coin, a lot of factors were in line for the event to potentially be a sustained nocturnal severe weather event. The previous day, the 19th, saw surface high pressure begin to exit the region eastward and allowing southerly return flow to work into eastern Nebraska and western Iowa. Tied in with mid to upper 70 dew points and steep mid-level lapse rates, a large area of 4000 plus J/kg CAPE values developed across eastern Nebraska and western Iowa and slowly built eastward. Additionally, effect bulk shear was consistently in the 40 to 50 kt range and low level shear roughly oriented to expected storm motion. As the evening progressed and the low level jet finally began to ramp up, boosting warm air advection and positive moisture flux, storms began to develop and eventually congeal. Organization, at least with regards to strong to severe criteria, was not immediate, waiting until around 5am local time to produce its first severe report. Severe reports then continued as the system moved southeast over the next 4 plus hours.
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 19, 5:28 AM CST, 32 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 628 AM CDT Mon Aug 19 2019 ...Updated Aviation Discussion... .SHORT TERM.../Today through Tuesday/ Issued at 356 AM CDT Mon Aug 19 2019 The main forecast concern is now focused on the potential MCS To roll through the CWA late tonight into Tuesday morning. Models have come into agreement on the timing, but still differ considerably wrt to location. NAM remains the furthest north, GFS is furthest south, while the 19.00z ECMWF is right in the middle and pegging central Iowa with heavy rain. The major changes to the forecast tonight were to increase pops and QPF considerably, especially between 06- 15z Tuesday. Leaned toward the HREF and ECMWF for pops tonight into Tuesday. Surface high pressure gradually slides east through the day today allowing for partial return flow into the state by this evening. Iowa is generally in zonal to northwest flow aloft and a decent mid- level shortwave tracks across out of the Dakotas into the CWA between 06-15z Tuesday. Higher confidence in the heavy rain potential than the severe weather potential with this shortwave. Good Theta-E advection and moisture transport into the state late tonight on the nose of the LLJ. Strong deep moisture convergence sets up northwest to southeast across the CWA between 06-12z Tuesday. Warm-layer cloud depths around 13-14kft with precipitable water values in the 1.5 to 2.0 inch range late tonight into Tuesday. Certainly there is the potential for another widespread 1 to 2 inches across the CWA by Tuesday morning, with some pockets of higher amounts as rainfall rates should be intense at times. Unless these storms train over an urban area, low confidence in widespread flash flood threat, especially as these storms look to be moving fairly progressively southeast. Although the Corfidi vectors nearly oriented with the storm motion, the training potential is there tonight. Albeit this will be a short duration as the shortwave and thus forcing for ascent is moving swiftly east enough and should clear the CWA by 15z Tuesday at the latest. As far as the severe weather potential, instability axis looks to be over central to southwest portions of Iowa and mainly looking at the potential for elevated hail threat and winds. There is some directional shear present to help with the rotating updrafts, but with the high freezing levels and the moist-tropical airmass in place, it'll be challenging for significant hail to reach the surface. And certainly with the amount of instability that looks to build into the state today, the DCAPE (and deep layer shear in place) will be high enough for the potential for damaging winds late tonight into Tuesday morning. The next concern is the heat on Tuesday. The MCS should be east of the CWA by 15z Tuesday and cloud cover looks to clear and allow for the heat to build into the CWA. Lowered max temps a degree or two with the potential for convective cloud debris hanging around the state. However, still confident Tuesday afternoon will be dangerously hot and humid over much of the CWA. .LONG TERM.../Tuesday Night through Sunday/ Issued at 356 AM CDT Mon Aug 19 2019 Confidence: Medium to High through Friday; Low into the Weekend Rather active pattern with general agreement between the models into the weekend. After tonights late night/early Tuesday MCS dives quickly southeast into the region another shortwave is expected to move over the established ridge in the southwest US and track east southeast toward Iowa by early Wednesday morning. The models show the H500 wave near western Colorado at 00z Wednesday. There is agreement between the GFS/Euro that the persistent quasi- stationary surface front over the region tonight will again drop just south of Iowa by 12z Wednesday. Aloft, a H850 front will be parked over northern Kansas east to about the Iowa/Missouri border. Thunderstorms are expected to develop over Nebraska just north of the H850 boundary in a zone of warm air advection. The MCS that develops should slide east southeast and just affect areas mainly south of I80 and especially closer to the Iowa/Missouri border. With expected outflow building south, any upstream activity that regenerates Wednesday will likely remain south of Iowa. The Euro captures this evolution better than the GFS at this time and will likely need to lower PoP a bit on Wednesday in the next package or two. Meanwhile, with lingering clouds through a portion of the day Wednesday, highs will be cooler than Tuesday and reach the lower 80s over southern sections and the upper 70s over the north. Through the day Wednesday sunny skies will return followed by a cooler and drier airmass will begin to settle in for the night. High pressure will bring a very pleasant night with lows in the lower 50s north to the upper 50s/lower 60s south. Thursday will be a great day with high pressure settling into the Great Lakes; providing light north northeast flow and plenty of sunshine. Afternoon highs will reach the mid 70s north to the upper 70s south. By Friday the models begin to diverge with the GFS once again speeding up the arrival of the next upstream trough. The European model is holding pat until Saturday afternoon before bringing in the next chance for showers. This appears to be the more correct solution as Great Lakes highs tend to retreat rather slowly compared to how the GFS usually handles their evolution. Though the current forecast accounts for some uncertainty in the models with a slight chance of thunderstorms as early as Friday evening and overnight into Saturday, some adjustments to precipitation timing will likely be needed. With the high holding on into Saturday, little if any change to afternoon highs is anticipated. A gradual moderation to morning lows will occur Friday into Saturday as a return to weak west southwest flow aloft allows for some warm air advection to creep into the region. With the models diverging already on Saturday, the GFS is nearly ending precipitation on Sunday while the Euro is just increasing stronger warm air advection/thunder chances into the area. With little consensus on Sunday between the GFS/Euro, a low confidence high has been projected in the mid 80s generally based on the GFS output. If the Euro is correct, highs would likely be about 5 to 10 degrees cooler with occasional showers/storms. && .AVIATION.../For the 12Z TAFS through 12Z Tuesday morning/ Issued at 624 AM CDT Mon Aug 19 2019 VFR conditions are forecast throughout the TAF period. However, with the potential for storms past 06z Tuesday, have introduced thunder mentioned at all TAF except OTM. Certainly there is the potential for MVFR to IFR cigs and visibility with the heavy rain. Timing and location is still in question. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...Podrazik LONG TERM...REV AVIATION...Podrazik
Hazardous Weather Outlook National Weather Service Des Moines IA 400 AM CDT Mon Aug 19 2019 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-200900- 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- 400 AM CDT Mon Aug 19 2019 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Thunderstorms are expected after midnight through the commute Tuesday morning. There is a marginal risk of severe storms with strong winds the main threat and isolated large hail a secondary threat. Brief heavy rainfall is also expected which may result in ponding of water in urban areas and possible street flooding during the morning commute Tuesday morning. By Tuesday afternoon, a period of hot and humid conditions will return to central Iowa with heat index values topping out above 100 degrees over central and southern Iowa. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday There is a chance of thunderstorms of additional thunderstorms again Tuesday night into Wednesday mainly over portions of southwest and possibly into central Iowa. The severe weather risk is low at this time. Additional thunderstorms are expected this weekend, but confidence remains low on timing for either Saturday or Sunday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected tonight, but rainfall reports would be appreciated. REV
The Des Moines radar (KDMX), 102 km away, was scanning. The volume nearest the first event began at 12:02 UTC.
18 heavy rain, 17 thunderstorm wind, 3 tornado, 2 hail, 1 lightning. Local standard time, as filed.
Coop observer, KCIM Radio, recorded heavy rainfall of 3.45 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 2.15 inches over the last 24 hours.
KWWL recorded heavy rainfall of 2.25 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 3.96 inches over the last 24 hours.
NWS employee recorded heavy rainfall of 2.29 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 3.68 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 3.45 inches over the last 24 hours.
Des Moines International Airport ASOS recorded heavy rainfall of 2.35 inches over the last 24 hours.
Public reported heavy rainfall of 2.07 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 3.45 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 2.32 inches over the last 24 hours.
Local media relayed public report of heavy rainfall of 3.25 inches. Beginning and end times estimated from radar.
Public reported heavy rainfall of 3.1 inches. Beginning time estimated from radar.
Public reported heavy rainfall of 4.5 inches. Beginning and end times estimated from radar.
Public reported heavy rainfall of 2.25 inches. Beginning and end times estimated from radar.
Trained spotter reported heavy rainfall of 2.55 inches. Beginning and end time estimated from radar.
Public reported storm total heavy rainfall of 2.30 inches. Beginning and end time estimated from radar.
Public reported a 12 inch diameter tree down. Time estimated from radar.
Trained spotter reported storm total heavy rainfall of 2 inches. Beginning and end times estimated from radar.
Emergency manager reported trees blown over on White Pole Road. A car ran into the downed trees. The location is estimated, as well as the time from radar.
Northern half of roof on a house blown into the trees. Time estimated from radar.
Law enforcement and Iowa DOT reported 3 semis blown over near the westbound rest stop near MM 80 on Interstate 80. Three additional semis were blown over in the eastbound traffic lanes in the same area. Time estimated from radar.
Automated mesonet site along Interstate 80 recorded a 60 mph wind gust.
The first of three tornadoes associated with a rapidly advancing QLCS. The tornado produced EF1 damage to a rural residence along with damage to trees in the area.
Media reported several small and medium size tree branches down.
Trained spotter reported 3 foot wide, 40 to 50 foot tall maple trees down, partial roof missing on shed, windows blown out of outbuildings, and wood swing set flipped over about 1 mile south of Lake Ahquabi State Park. Time estimated from radar.
Public reported penny sized hail via the mPING app.
NWS employee reported tree down over 61st street south of Merle Hay Mall. Time estimated from radar.
Public reported, via mPING, trees uprooted or snapped; roof blown off. Time estimated from radar.
The second of three tornadoes associated with a fast moving QLCS. The particularly strong tornado moved across rural Warren county producing mainly crop and tree damage. However, the tornado encountered the several large steel buildings with I-beam construction. Significant damage occurred to these buildings with some being totally destroyed producing the EF3 damage. The tornado continued to the southeast beyond this area remaining in rural crop and woodland areas.
Emergency manager reported structure damage to outbuildings, hay bales blown across/on the road, and power lines down. Time estimated from radar.
Emergency manager reported several structures damaged, including machine sheds, grain elevators, and power lines down. Time estimated from radar.
Public reported, via mPING app, trees uprooted or snapped; roof blown off.
Iowa DOT reported road closed due to downed power lines. Time of greatest winds estimated from radar.
Chariton Municipal Airport AWOS recorded wind gusts of 58 mph.
Law enforcement reported a semi blown over on mile long bridge north of Knoxville, including a reported serious injury. Time estimated from radar.
Emergency manager reported a house fire started by lightning.
The last of three tornadoes produced by a fast moving QLCS. Tornado began west of Tracy in rural areas producing only crop and tree damage. As the tornado moved through town, it produced mainly tree and minor structural damage to buildings in the town. The tornado dissipated on the east side of Tracy.
Law enforcement reported house, barn and outbuildings heavily damaged by winds. Multiple trees were also reported downed. Time estimated from radar.
Iowa DOT RWIS station along US Highway 63 recorded 58 mph wind gusts.
Emergency manager reported ping pong ball sized hail.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2019Every state in 2019This day in weather historyThe tornado archive for Iowa, 2019Warnings in Iowa, August 2019
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: 849781, 849782, 849783, 849784, 849785, 849786, 849787, 849788, 849789, 849790, 849791, 849778, 849764, 849776, 849794, 849773, 849797, 849750, 849793, 849754, 849752, 849756, 849758, 850373, 849765, 849760, 849761, 849762, 849792, 850374, 849767, 849769, 849795, 849770, 849771, 849777, 849774, 850375, 849780, 849779, and more.