After an early morning round of dissipating thunderstorms that brought gusty winds, late afternoon storms formed over eastern Iowa and northwest Illinois. These storms produced numerous hail reports, and eventually produced damaging winds in the late evening hours as they moved into Illinois.
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 DVN wrote it up.
After an early morning round of dissipating thunderstorms that brought gusty winds, late afternoon storms formed over eastern Iowa and northwest Illinois. These storms produced numerous hail reports, and eventually produced damaging winds in the late evening hours as they moved into Illinois.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at Jun 15, 5:33 AM CST, 2 hours 36 minutes earlier.
Area Forecast Discussion National Weather Service Quad Cities IA IL 633 AM CDT Thu Jun 15 2017 ...AVIATION UPDATE... .SYNOPSIS... Issued at 352 AM CDT Thu Jun 15 2017 Only a few isolated showers remained over the forecast area, mainly south of I-80 at 2 am, with a larger MCS on area radar mosaics dropping south into the I-70 corridor in MO. The airmass remained warm and still somewhat humid over the local area, with slightly drier air lagging behind a very weak cool front reaching from far NE IA W-SW into eastern NE. High level cloud cover streaming north from the MO convection was keeping skies mainly overcast. Aloft, the flow was mainly westerly and weakly cyclonic as far south as northern IA around the upper low churning over south central Canada. && .SHORT TERM...(Today and Tonight) ISSUED AT 352 AM CDT Thu Jun 15 2017 A short reprieve from convection is likely this morning through this afternoon, then chances for thunderstorms return this evening and lingering into Friday. A period of in-building subsidence with dry air aloft and weak ridging at the surface will provide mostly sunny skies through afternoon. Light surface winds and pockets of moisture from yesterday's rainfall will likely hold dewpoints in the 60s, while temperatures return back to the upper 80s to lower 90s, based on near full sunshine and similar 850 mb temperatures as the past several days. By early evening, the approaching weak surface front and next upper level shortwave will interact with developing moisture return aloft to trigger at least scattered thunderstorms, initially in the west and northwest, where chance pops are maintained. SPC has a marginal risk across the portions of east central and southeast IA into far northeast MO, where there may be sufficient instability to sustain strong to severe storms with a complex that may move during the evening from the plains. The main threat would likely be damaging winds and heavy rainfall, with a lower risk for large hail. This activity may then overspread most of the forecast area overnight, but in a non-severe mode as MUCAPES are progged to wane. With slightly lower dewpoints and cool pools from convection, have stayed with lows close to model guidance, in the mid to upper 60s, which would be cooler than the previous several nights. .LONG TERM...(Friday through Wednesday) ISSUED AT 352 AM CDT Thu Jun 15 2017 Friday Very warm and increasingly humid. SSW sfc winds will advect mid to upper 60 dewpoints northward into E Iowa/NW Illinois. Maintained the model blend max temps in the mid to upper 80s. Similar to several other days this week, a ~20 C 850mb thermal ridge or elevated mixed layer is forecast to spread in from the SW, encompassing about the SW half of the CWA by the afternoon. A few locations within this area could reach near 90 F depending on the amount of sunshine. Thunderstorm Outlook: The Storm Prediction Center has a slight risk for severe thunderstorms for approximately the western half of the CWA and a marginal risk further east. Environmental kinematics (0-6 km bulk shear around 40 kts) and thermodynamics (MUCAPE 2500-4000 J/kg) displayed on forecast soundings are favorable for some strong or severe thunderstorms - damaging winds and large hail the primary threats. However, thunderstorm chances are actually fairly low during the day (20-30%) when the local area is void of a low-level synoptic boundary or mid-level wave. Further to the NW, across north-central Iowa, there are better chances for thunderstorms to develop during the afternoon along a weak zone of low-level convergence. This boundary is forecast to slide to the SE with time. Confidence: Confidence on areal coverage of storms for Friday evening and night remains low. As far as model solutions go, the synoptic scale models are more aggressive than the 4km NAM or NMM are. But kinematic fields show a substantial ramp up in the nocturnal low-level jet and associated WV transport which should assist at least scattered storm development. Right now, PoPs are only 40-50% because of the low confidence on widespread coverage. Saturday The first half of the weekend will feature a strong shortwave trough rolling through the Midwest. Strong deep layer shear will accompany this trough. The interaction of a hot and humid air mass (+1.75" PWATs) and height falls or cooling aloft is a setup conducive for severe weather. As usual, there are timing and coverage difference among the models. The ECMWF/GFS suggest an afternoon through evening event. While the NAM/CMC are later, mostly overnight. Stay tuned to forecast updates over the next few days as we try to sort out the details. Sunday through Tuesday Models in agreement on a pattern change to NW 850-500mb flow and near normal temps/lower humidity. Aside from occasional chances for showers or storms, much of this 3 day stretch looks dry. The overall threat for heavy rain is very low. Tuesday Night through Thursday To varying degrees, the ECMWF/GFS are in agreement on advecting the warm elevated mixed layer over E Iowa/NW Illinois, with potentially a sfc warm front setting up near or across the local area. The forecast for this mid to late week period is trending toward warmer temps, higher humidity, and better chances for thunderstorms. Uttech && .AVIATION...(For the 12Z TAFS through 12Z Friday Morning) ISSUED AT 633 AM CDT Thu Jun 15 2017 VFR conditions with light winds will be the rule today through the afternoon. There is a low potential for late afternoon thunderstorms in the CID and DBQ vicinity, then scattered thunderstorms look more likely in the evening and overnight over the entire area. This potential has been narrowed down to the most likely 4 hour period for now, advertised as prob30 groups. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && SYNOPSIS...Sheets SHORT TERM...Sheets LONG TERM...Uttech AVIATION...Sheets
Hazardous Weather Outlook National Weather Service Quad Cities IA IL 454 AM CDT Thu Jun 15 2017 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-161000- Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson- Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson- Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll- Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson- Warren-Hancock-McDonough-Scotland-Clark- 454 AM CDT Thu Jun 15 2017 This Hazardous Weather Outlook is for portions of north central Illinois...northwest Illinois...west central Illinois...east central Iowa...northeast Iowa...southeast Iowa and northeast Missouri. .DAY ONE...TODAY AND TONIGHT Thunderstorms are possible across the outlook area tonight. There is a low potential for severe storms, mainly west of a line from Vinton to Mount Pleasant Iowa to Kahoka Missouri. The main severe weather threats are damaging winds and large hail. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY There are periodic chances for thunderstorms Friday through Saturday night. There is a slight risk for severe thunderstorms on Friday along and west of a line from Manchester, Iowa to Walcott, Iowa to Macomb, Illinois. The remainder of the outlook area has a marginal risk. There is a low chance for storms Friday afternoon. A better chance exists during the evening or overnight. Damaging winds and large hail are possible with the strongest storms. Thunderstorm coverage will likely remain scattered. There is a slight risk for severe thunderstorms on Saturday across the entire area. Damaging winds and large hail are the primary threats. The most likely timing of storms is late afternoon into Saturday night. However, confidence on exact timing and coverage of storms is low since this is several days away. Please stay tuned to forecast updates through this week. On Saturday afternoon, forecast peak heat indices may reach the mid to upper 90s along and south of highway 34, west of Galesburg, Illinois. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed tonight over portions of eastern Iowa and far northeast Missouri. Sheets/Uttech
The Quad Cities radar (KDVN), 78 km away, was scanning. The volume nearest the first event began at 14:07 UTC.
20 hail, 12 thunderstorm wind. Local standard time, as filed.
Tree limbs were reported down in southeast corner of Mt Vernon and power was knocked out to the city of Mt Vernon. The time was estimated to have occurred with the early morning storms.
A spotter reported the hail near I-380 mile marker 32.
This report was received through social media.
Large trees limbs were reported blown down on Alice Road, between Alice and Toddville.
The report was relayed from law enforcement.
The hail was reported along Interstate 380.
A large tree was blown down.
Estimated winds of 60 to 70 mph brought branches down at the intersection of Highways 13 and 151.
An 18 inch diameter tree was blown down.
Trees and power lines down across Highway 38. The public report time is estimated from radar data.
Winds were measured by the Davenport Airport, KDVN ASOS, with a peak wind of 62 mph, and maximum sustained wind of 48 mph for a 5 minute period ending at 1002 PM.
Winds were measured by Iowa DOT RWIS at I-80 and I-280 interchange.
Numerous large tree branches were blown down with a few trees blown over.
Numerous reports and photos of a large tree branch blown down and as well as reports of trees blown down over much of Bettendorf. Reports were relayed through social media.
Wind gusts of 65 TO 70 mph were reported, with several 3 to 4 inch limbs blown down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2017Every state in 2017This day in weather historyWarnings in Iowa, June 2017
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: 694445, 694389, 694390, 694392, 694394, 694395, 694438, 694397, 694405, 694406, 694408, 694410, 694413, 694414, 694443, 694416, 694439, 694442, 694417, 694428, 694431, 694446, 694447, 694448, 694452, 694449, 694450, 694451, 694432, 694433, 694434, 694435.