Early June activity continued with yet another day of convective activity that included severe storms and heavy rainfall. A relatively stationary boundary was situated across the western and southern portions of the state, acting as a focus for convective activity throughout the morning and early afternoon as convection lingered from the previous day.
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.
Early June activity continued with yet another day of convective activity that included severe storms and heavy rainfall. A relatively stationary boundary was situated across the western and southern portions of the state, acting as a focus for convective activity throughout the morning and early afternoon as convection lingered from the previous day. While there was not much opportunity to recover thermodynamically due to cloud cover, MUCAPE values remained in excess of 1000 J/kg in areas of convection and up to 2000 to 3000 J/kg in areas just to the west or south of the convection. Supporting parameters suggested the opportunity for a few organized storms with effective shear in the 30 to 40 kt range and low level helicity in the 100 to 200 m2/s2 neighborhood. Another concern was the potential for training storms with the stationary boundary in place and expectations of low level jet aided initiation in the overnight hours.
In the end, a few severe storms were seen during the afternoon and evening hours, including hail approaching 2 inches in diameter, wind gusts to near 70 mph, and a vehicle heavily damaged from a lightning strike. Heavy rainfall was also experienced, though fortunately most locations were spared the heaviest totals, with most in the 2 to 3.5 inch range and a couple in excess of 4 inches.
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 10, 3:17 AM CST, 1 hour 23 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 417 AM CDT Sun Jun 10 2018 .SHORT TERM.../Today through Tonight/ Issued at 416 AM CDT Sun Jun 10 2018 Rest of this Morning... Focus is on eastern Nebraska. At 08z Sun, GOES-R IR imagery clearly picking up on an MCS that was developing over east-central Nebraska and slowly propagating towards Iowa. This MCS cluster is associated with a shortwave/vort max area that is being initiated well with most models. GOES-R showed cloud top temps cooling as SPC Mesoanalysis showed the cap breaking over the heart of the cluster. Well-phased with PVA of this system is a 40 to 50KT LLJ oriented SW- NE. Along the nose of this LLJ is strong low-level frontogenetical forcing that has likely contributed to ascent processes to help these storms punch through this cap. MUCAPE values are roughly around 2000 J/KG from these storms and through Iowa. The orientation of the instability axis and frontogenetical forcing is NW-SE, so am expecting the general cluster of storms to favor a more easterly/southeasterly track as the near the DMX CWA. Timing-wise, am expecting these storms to be in the west-central portion of the DMX CWA around 12z to 18z... which is not a climatologically favored time for severe weather. In short, forcing parameters wane through this time-frame, so would expect storms to gradually weaken as they traverse through west-central Iowa. QPF amounts are generally one-tenth to one-quarter of an inch. Temperatures today will be tricky. Somewhat thick, low-level stratus will be in place over northeastern Iowa associated with the previous days rainmaker of a shortwave. These clouds will slowly move northeastward throughout the daytime with this system. If clouds linger into the afternoon, Mason City & Waterloo may struggle to get out of the mid 70s... while southwestern Iowa may make flirt with the mid 90s if the track and subsequent cloud cover from the Nebraska system keeps the easterly component in its track. If the storms hold to the Des Moines metro during the early afternoon, max temperatures may be held to the low 80s... if the system dissipates more rapidly than expected, low 90s would seem more prudent... so for now, am near the middle. This Afternoon/Tonight... Another round of moderate to heavy rainfall possible tonight as the LLJ mentioned above creeps into western Iowa. Models have had a westward trend with this LLJ, so will need to watch and see if this continues. If the trend does continue, axis of highest precip amounts will need to be shifted to west of I-35. At this point in time, Axis of heaviest precip from Mason City through Marshalltown. Important to note that Mason City area has received substantial rain over the past few days... so this rainfall is certainly not going to alleviate flooding issues in that area. MUCAPE values to be near 1000 J/KG. PWATs around 1.5 to 1.75 inches... +1 to +2 std dev once again. Ultimately, heavy rainfall/flooding potential in already rain- soaked areas biggest threat. Severe weather threat fairly low, with damaging winds the secondary threat. .LONG TERM.../Monday through Saturday/ Issued at 416 AM CDT Sun Jun 10 2018 Potential for some elevated convection to be ongoing Monday morning across the northeast and it is possible some convective elements will linger through the morning in that region. The activity should diminish by late morning and into the early afternoon as drier mid level air arrives. Elsewhere, a capping inversion around 800 mb should limit any convective potential until later in the day. Over all trends are a bit slower on the upper level short wave and surface boundary arriving on Monday. Storms should develop as the boundary arrives by mid to late afternoon as the cap erodes. Similar thinking to SPC SWODY2 with generally multicells developing in a highly unstable environment. Broad CAPE through the mid levels will supports good updraft accelerations and large hail good 0-3 km Theta-e differences of 30-35k and DCAPE approaching 1500 will support cold pool development and lead to a damaging wind threat. All guidance is suggesting at least a weak low pressure depression lifting up along the boundary by the afternoon. While the GFS wind fields are not capturing this, there should be a little better deep and low level shear in place immediately north and east of the surface low. This region could become supportive of isolated supercell development and could have an attendant tornado threat in addition to very large hail and damaging wind gusts. Locally heavy rainfall will remain a concern until the boundary finally exits central Iowa as PWATs increase to 1.75-2 inches ahead of the boundary. Initial storm motions will also be seasonably slow and in the 5 to 20 kt range. Any supercells in particular could drop a significant amount of rain given expected slow motions. Finally, northeast Iowa could again be the target for heavy rainfall as more widespread storm development looks to focus on that region. Will certainly need to monitor that region as much of the Shell Rock and Cedar River basins are running high. Storms will end from west to east Monday night and will be followed by high pressure. Tuesday should be an outstanding day with lighter winds, dew points in the 50s leading to low humidity and high temperatures in the upper 70s to mid 80s. Wednesday will be similar though with the area of high pressure beginning to shift east, temperatures and dew points will be a bit higher that Tuesday. There will be a low chance for late afternoon thunderstorms over the northwest as theta-e advection begins to move back into the state. More widespread storms are expected Wednesday night into early Thursday. Additional scattered storms could occur Friday into Saturday as the upper flow becomes more southwesterly allowing the weather to remain active. && .AVIATION.../For the 06Z TAFS through 06Z Sunday night/ Issued at 1205 AM CDT Sun Jun 10 2018 Some stratus to deal with across eastern TAF's tonight. Additional TSRA possible across southern TAF locations. Sunday should remain mostly dry in the daytime hours with VFR cigs. Thunderstorms return to northern/eastern TAF locations after 11/03Z producing MVFR conditions. && .HYDROLOGY... Issued at 416 AM CDT Sun Jun 10 2018 Primary concerns for river flooding remains along the Winnebago, Shell Rock and Cedar Rivers and along some smaller streams including Willow Creek and Flood Creek. Pockets of heavy rainfall occurred with Saturday evenings storms especially along the Winnebago basin and along the Shell Rock just south of Nora Springs. Stream gages have resumed rising along the Shell Rock river at Marble Rock and Packard and there is another surge coming down the Winnebago that is 1-2 kcfs higher than what moved through the system 24 hrs ago. This could place the Shell Rock river level at Greene near to higher than what was observed Saturday morning though a bit difficult to forecast with the local surge currently arriving followed by the Winnebago River flow. The Winnebago flow may just attenuate and slow the fall at Greene rather than cause an additional rise. The currently forecast near Clarksville would not directly impact the community itself but would place water levels less than 1 ft from impact Highway 188 south of town. Additional storms will be possible across this area Sunday night into Monday morning and again late Monday into Monday night. River levels should be receding prior to this activity at most locations therefore it would take another heavy rain event upstream to overturn the trends. Another very heavy rain event would eclipse current levels. The Cedar River Basin is in a bit better shape though upstream, flooding is forecast near Charles City and certainly some Agricultural flooding is occurring. Again though, it will likely need another very heavy rain event to occur to cause significant issues. That said, the potential is there given the current setup through Monday night. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...Kotenberg LONG TERM...Donavon AVIATION...FAB HYDROLOGY...Donavon
Hazardous Weather Outlook National Weather Service Des Moines IA 448 AM CDT Sun Jun 10 2018 IAZ004>006-015-016-023>025-033>038-044>050-057>062-070>075- 081>086-092>097-111000- Emmet-Kossuth-Winnebago-Palo Alto-Hancock-Pocahontas-Humboldt- Wright-Sac-Calhoun-Webster-Hamilton-Hardin-Grundy-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- 448 AM CDT Sun Jun 10 2018 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Scattered thunderstorms are possible today and into tonight. Isolated severe storms are possible with large hail and damaging winds. Locally heavy rainfall could occur with any storms. .DAYS TWO THROUGH SEVEN...Monday through Saturday Additional storms are possible Monday afternoon and night. A few severe storms will be possible with large hail and damaging winds. Isolated tornadoes may also occur. In addition, locally heavy rainfall may occur. Scattered storms are possible at times from Wednesday night through Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed at times through Monday night. IAZ007-017-026>028-039-111000- Worth-Cerro Gordo-Franklin-Butler-Bremer-Black Hawk- 448 AM CDT Sun Jun 10 2018 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Scattered thunderstorms are possible today and into tonight. Isolated severe storms are possible with large hail and damaging winds. Locally heavy rainfall could occur with any storms. River Flood Warnings are in effect along the Winnebago, Shell Rock and Cedar River basins. .DAYS TWO THROUGH SEVEN...Monday through Saturday Additional storms are possible Monday afternoon and night. A few severe storms will be possible with large hail and damaging winds. Isolated tornadoes may also occur. In addition, locally heavy rainfall may occur. Scattered storms are possible at times from Wednesday night through Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed at times through Monday night.
Special Weather Statement
National Weather Service Des Moines IA
523 AM CDT SUN JUN 10 2018
IAZ033-044-045-101100-
Sac IA-Carroll IA-Crawford IA-
523 AM CDT SUN JUN 10 2018
...Line of Storms May Produce Penny to Dime Size Hail...
At 522 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Whiting to Denison. Movement was east at
20 mph.
Dime size hail and winds in excess of 30 mph will be possible with
these storms.
Locations impacted include...
Denison, Sac City, Manning, Lake View, Odebolt, Black Hawk Lake,
Schleswig, Wall Lake, Manilla, Schaller, Early, Dow City, Charter
Oak, Arcadia, Breda, Vail, Templeton, Westside, Kiron and Deloit.
LAT...LON 4221 9567 4221 9532 4247 9532 4248 9539
4256 9539 4256 9499 4186 9487 4187 9567
TIME...MOT...LOC 1022Z 261DEG 19KT 4209 9613 4203 9537
KotenbergThe Des Moines radar (KDMX), 149 km away, was scanning. The volume nearest the first event began at 10:41 UTC.
14 heavy rain, 6 thunderstorm wind, 4 hail, 2 lightning, 1 flood. Local standard time, as filed.
Flooding is occurring along Flood Creek with several roads inundated.
Public reported heavy rainfall of 2.89 inches over roughly the last 24 hours.
Coop observer recorded heavy rainfall of 2.61 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.60 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 3.45 inches.
CoCoRaHS observer recorded heavy rainfall of 2.15 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.24 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.00 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.12 inches over the last 24 hours.
CoCoRaHAS observer recorded heavy rainfall of 2.38 inches over the last 24 hours.
CoCoRaHS observer recorded heavy rainfall of 2.27 inches over the last 24 hours.
Coop observer recorded heavy rainfall of 2.5 inches over the last 24 hours.
Broadcast media, KICD Radio, relayed public report of heavy rainfall of 2.2 inches near Lost Island Lake over the last 24 hours.
KICD Radio relayed a public report of heavy rainfall of 4.5 inches over the last 24 hours.
KICD Radio relayed public report of heavy rainfall of 4.0 inches over the last 24 hours.
NWS Employee reported that a vehicle was struck by lightning at exit 100 on Interstate 80, badly damaging the vehicle. There were no injuries to the 3 passengers.
Public reported nickel sized hail.
NWS employee reported nickel sized hail.
Trained spotter reported a few large tree limbs roughly 4 to 6 inches in diameter down just southwest of Murray. This is a delayed report and time estimated from radar.
Public reported multiple trees down, including one snapped at the trunk that was approximately 18 inches in diameter. Several power lines were also reported down in town.
Law enforcement reported trees and power lines down in Creston. Time estimated from radar.
Public reported wind driven hail up to golf ball sized lasting about 15 minutes. Siding on the south side of the house was completely destroyed.
Creston Municipal Airport recorded a 64 mph wind gust.
An Iowa DOT RWIS station measured a 63 mph wind gust.
Lightning struck an internet antenna on the roof. The parts of the antenna were found laying in the grass about 10 yards away. The home was properly grounded, but still led to damage of most of the electronics in the home, including many of the electrical outlets and led some smoke but no fire inside the home. The strike also broke open a water line near the exit point in the basement. Homeowner was home at the time.
Lamoni Municipal Airport ASOS recorded a 67 mph wind gust.
Broadcast media, KICD, relayed reports of quarter sized hail.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2018Every state in 2018This day in weather historyWarnings 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: 767253, 761898, 761900, 761901, 761902, 761904, 761905, 761906, 761908, 761909, 761910, 761911, 761913, 761916, 761918, 761881, 761882, 761883, 761887, 761891, 761892, 761893, 761894, 761895, 767023, 761896, 761897.