An occluded/occluding surface low pressure system slowly worked its way into western and southwest Iowa during the morning and afternoon of the 25th. Given its location, Iowa was situated north of the warm front, which was much further south into central Missouri.
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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.
An occluded/occluding surface low pressure system slowly worked its way into western and southwest Iowa during the morning and afternoon of the 25th. Given its location, Iowa was situated north of the warm front, which was much further south into central Missouri. Even so, the environment was cool yet fairly saturated in the low levels with temperatures in the low to mid 70s and dew points in the mid to upper 60s.
Low level flow was up over the occluded front, providing additional lift, within an environment of around 1000 J/kg MUCAPE, effective shear up to around 40 kts, lifted condensation levels approaching 500 m at times, and plenty of low level 0-1 km storm relative helicity in excess of 200-300 m2/s2. All in all, it was a ripe day for general moderate to heavy rainfall, funnel clouds, and weak landspout tornadoes. The majority of the action revolved around heavy rainfall that totaled in excess of 3 inches in many locations, but also involved multiple funnel cloud reports and a lone brief tornado near Delphos in Ringgold County.
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 Jun 25, 5:22 AM CST, 38 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 622 AM CDT Mon Jun 25 2018 .SHORT TERM.../Today through Tuesday/ Issued at 239 AM CDT Mon Jun 25 2018 An unseasonably strong upper low was over the western high plains early this morning and it will drift east across Nebraska today. The associated surface low was over south central Nebraska at 0700 UTC. The surface low should slowly move east this morning and be over eastern Nebraska by early afternoon with a warm front extending southeast into northern Missouri. Thunderstorms over north central Iowa were decaying over the past few hours and by this morning we should be in a relative minimum of precipitation across the area. The CAMS eject the northeast precipitation shield associated with the large MCS across the plains into central Iowa this morning. The precipitation should weaken as it moves northeast this morning. Meanwhile, central Iowa will remain in cool easterly flow north of the warm front to the south. The warm front should move northeast into southwest Iowa late this afternoon and remain tied to the surface low over eastern Nebraska. A favorable veering wind profile will be in place should surface based instability develop near and just northeast of the warm front. Assuming there is adequate instability, thunderstorms should develop late in the day and move northeast through the evening. the best severe chances are early near the warm front. The storms should be more progressive than last evening/s storms limiting flash flood potential. A risk of flash flooding remains and will highlight in messaging, but will not issue a watch given the somewhat isolated risk. The surface system will continue to move northeast late tonight and Tuesday. Additional storms are expected to develop near the cold front Tuesday afternoon. The severe potential is depicted on the SPC Day 2 Outlook. .LONG TERM.../Tuesday Night through Sunday/ Issued at 239 AM CDT Mon Jun 25 2018 The upper low moves out of the picture by Wednesday and it will be followed by rising heights across the upper midwest. A weak surface high should provide fair weather for central Iowa Wednesday with seasonable temperatures. The upper ridge builds north into the lower Ohio Valley late this week with another upper trough over the northern Rockies. The surface reflection of this should result in a surface front north of the state by the end of the week. With return flow and warm advection, there is a risk of some midweek storms late Wednesday night or early Thursday. Then the there will a return of above normal temperatures and drier weather late in the week. The warm dry weather does not last too long as the upper trough moves east pushing the synoptic front back into the state by this weekend. This will result in more unsettled weather and cooler temperatures. && .AVIATION.../For the 12Z TAFS through 12Z Tuesday morning/ Issued at 617 AM CDT Mon Jun 25 2018 An area of showers and thunderstorms will move northeast into central Iowa today. This activity will weaken as it moves northeast. Expect VFR conditions with this activity. Stronger thunderstorms are forecast to develop late this afternoon. Only forecast VCNTY thunder at the TAF sites due to low confidence on timing and intensity. Lower ceilings are expected late in the period at KMCW and KALO. && .HYDROLOGY... Issued at 239 AM CDT Mon Jun 25 2018 Several rivers remain in flood early this morning. The overnight heavy rain across north central Iowa will impact the upper Des Moines, Iowa and perhaps some of the tributaries of the Cedar. QPF today and Tuesday is less than what occurred last evening since the storms should be progressive. However, additional heavy rainfall especially in the Raccoon and Des Moines basin would not be welcome. Today/s river forecast will account for the expected rainfall. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...Johnson LONG TERM...Johnson AVIATION...Johnson HYDROLOGY...Johnson
Hazardous Weather Outlook National Weather Service Des Moines IA 416 AM CDT Mon Jun 25 2018 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-260930- 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- 416 AM CDT Mon Jun 25 2018 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Flood Warnings remain in effect for portions of the area. Please refer to the National Weather Service website at weather.gov/desmoines for further details. Thunderstorms are forecast this afternoon and evening. Isolated severe storms are possible, especially in central and southwest Iowa. All modes of severe weather is possible including large hail, damaging winds and isolated tornadoes. Locally heavy rain is possible across the entire area tonight. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Flood Warnings are expected to continue for portions of the area through into early next week. Please refer to the National Weather Service website at weather.gov/desmoines for further details. Scattered severe thunderstorms are possible over southeast Iowa, southeast of Des Moines, on Tuesday afternoon and evening. Large hail and damaging winds appear to be the primary threats. Additional thunderstorms will be possible Thursday morning. It is too early to determine the potential for severe weather during that time. Hot and humid weather will return to the region late in the week with heat indices approaching 95 to 105 F over the central to southern half of the region both Thursday and Friday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening across central Iowa. Spotter activation will likely be needed Monday afternoon and evening. Spotter activation may be needed Tuesday over portions of central to southern Iowa.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
516 AM CDT MON JUN 25 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0515 AM HEAVY RAIN GARNER 43.10N 93.60W
06/25/2018 M1.75 INCH HANCOCK IA TRAINED SPOTTER
TOTAL RAINFALL FROM SUNDAY NIGHT STORM.
&&
REVThe Des Moines radar (KDMX), 23 km away, was scanning. The volume nearest the first event began at 11:55 UTC.
25 heavy rain, 4 flash flood, 2 funnel cloud, 2 flood, 1 tornado. Local standard time, as filed.
Des Moines International Airport ASOS recorded heavy rainfall of 2.99 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 2.24 inches over the last 24 hours.
Prairies City AWOS recorded heavy rainfall of 2.74 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.57 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 3.86 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.51 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.17 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.03 inches over the last 24 hours.
Des Moines International Airport ASOS recorded heavy rainfall of 2.66 inches so far.
Public reported heavy rainfall of 3.10 inches and included a picture of their rain gage.
Public reported heavy rainfall of 2.86 inches. They also reported that water was over the road at SW 9th during the height of the rainfall and some vehicles were stranded. This is a delayed report.
WHO relayed heavy rainfall report at their station of 2.67 inches via social media. WHO VIA SOCIAL MEDIA.
Public reported heavy rainfall of 3.08 inches.
Trained spotter reported heavy rainfall of 2.10 inches and that the creek in Windflower Park was moving swiftly and out of its banks in spots. They noted that it does not happen often.
CoCoRaHS observer reported heavy rainfall of 2.09 inches.
Public reported heavy rainfall of 3.14 inches and that roadside ditches were full of water.
Public reported heavy rainfall of 4 inches.
Broadcast media relayed a public report of heavy rainfall of about 4 inches.
Public reported heavy rainfall of 3.5 inches from yesterday through early this morning.
Trained spotter near Waveland Golf Course reported heavy rainfall of 2.12 inches yesterday through this morning.
Public reported heavy rainfall of 2.51 inches from yesterday and overnight.
Trained spotter reported heavy rainfall of 3.86 inches yesterday and overnight.
Trained spotter near Des Moines International Airport reported heavy rainfall of about 3 inches yesterday and overnight.
Trained spotter reported a persistent funnel lasting over 5 minutes.
This tornado touched down in the hamlet of Delphos with tree debris being tossed around. A rather diffuse funnel for much of its existence, very little damage occurred with this tornado. The event was captured on video by a few different storm chasers.
Chaser video shows a funnel cloud, but unknown if it reached the ground. This is a delayed report.
Trained spotter reported heavy rainfall of 2.97 inches from last night through early this morning.
Public reported significant street flooding with fast running water. Possibly due to low spot, but estimated depth of 12 to 15 inches, with a partially submerged vehicle. Time estimated from radar.
State Patrol reported flooding on Interstate 35 northbound at mile marker 62. The left lane was blocked due to water. Water was reported to have receded in about 10 to 15 minutes. This is a delayed report.
Public reported heavy rainfall of 3.25 inches from about 9 pm through 10:30 pm last night. This is a delayed report.
Public reported that heavy rainfall caused significant street flooding in and around Davis Ave and South Union St Monday evening. Moving water was of unknown depth. This is a delayed report.
Law enforcement reported that US 65 Southbound off-ramp at Exit 77 in Pleasant Hill was under water. The water receded after nearly 5 hours and 45 minutes. Ramp was back open at the time of the report, this is a delayed report.
Flooding continued across portions of Jasper County near the Baxter area and at the Colfax fairgrounds.
Flooding continued across eastern portions of the county in and near Runnells and Mitchellville.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2018Every state in 2018This day in weather historyThe tornado archive for Iowa, 2018Warnings in Iowa, June 2018
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: 764580, 764583, 764585, 764588, 764589, 764590, 764591, 764592, 764564, 764565, 764566, 764567, 764568, 764570, 764571, 764572, 764573, 764575, 764579, 764582, 764584, 764586, 764587, 764559, 756127, 764560, 764577, 764562, 764563, 764576, 764569, 764574, 767923, 767935.