An isolated thunderstorm in a very moist, unstable air mass resulted in a damaging wind report.
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.
An isolated thunderstorm in a very moist, unstable air mass resulted in a damaging wind report.
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 Jul 11, 10:54 PM CST, 3 hours 36 minutes earlier.
Area Forecast Discussion National Weather Service Quad Cities IA IL 1154 PM CDT MON JUL 11 2016 .UPDATE... Issued at 1153 PM CDT Mon Jul 11 2016 Area radars show a bowing MCS from Mason City through Des Moines curving w-sw toward Omaha. This was moving east around 40 to 45 mph and into an environment with less favorable shear than where it originated over western IA and eastern NE earlier this evening However, there is still adequate instability to sustain updrafts and storms along the outflow boundary at surface based CAPES were 2000 j/kg or greater over eastern IA. The main threats look to be wind gusts of 45 mph and heavy downpours as it will reach the western forecast area counties between midnight and 1 am. This is already trended in the latest updates. && .SYNOPSIS... Issued at 339 PM CDT Mon Jul 11 2016 The latest SFC analysis was indicating a low pressure acrs central SD, with a cool front dropping off south and southwest of there into the southwestern plains. An associated warm front extended from west- to-east acrs far southern MN into central/southern WI. Thus the DVN CWA fully bathed in this system's capped warm-moist sector, with SFC DPTs hanging on generally in the mid 70s driving current heat index readings in the mid 90s to around 100. The current water vapor loop was indicating the main upper low rolling northeastward out of northeastern MT into south central Canada as it encounters upper midwest/GRT LKS upper ridge complex. && .SHORT TERM...(This Evening through Tuesday) ISSUED AT 339 PM CDT Mon Jul 11 2016 Tonight...elevated agitated CU field in ongoing sfc pressure fall areas acrs western IA/MO RVR Valley into southwestern MN to the system's triple point, suggesting region of this afternoon/evening initiation as the cap weakens (if it does acrs the south half of IA). SFC based CAPES in western IA 4000 J/KG or higher but still capped off for now...best ongoing llvl convergence in southeastern SD and acrs southern MN ATTM. After strong to severe convection erupts in these northern-northwestern areas, current propagation vectors suggest it to feed south and southeast into increasing SSW LLJ of 40- 50 KTs acrs western into central IA through midnight. Will have to watch the northwestern CWA(generally northwest of a CID to Manchester-Dyersville IA line) after 11 PM CDT for the northeastern portions of this convective system to push in from the northwest and possibly still be able to produce strong wind gusts. There may even be a severe threat with lingering robust MUCAPEs for that time of night and if a bowing segment is being helped along by llvl cold pool effect. But the convection must battle the cap and get SFC based for that to happen. Otherwise, expect the convective system to weaken into sunrise Tue morning as it spills east of the MS RVR acrs much of the rest of the DVN CWA. With elevated high THTA-E feed and PWATs of 1.8 to over 2 inches, locally heavy rain will be another threat and possibly the more widespread one. Storm outflow cooled lows in the upper 60s to lower 70s acrs most of the area, otherwise they would be held up in the mid to upper 70s without precip. Tuesday...Will walk out the morning's weakening convection south and east of the CWA through mid to late morning as the LLJ temporarily veers and weakens diurnally. Then the same old story of how much the local area can recover from morning convective debris to become unstable enough to allow afternoon redevelopment...especially with stronger dynamics and upper wave shunted further to the north of the region. Recovering southerly LLVL flow may impinge on the morning storms remnant outflow boundaries mainly south and southeast of the CWA with new development occurring mainly acrs these areas by late afternoon and not in the local area. Other models drift the outflow boundary back up close to the main warm front into the southern and central CWA to act as a focus for later afternoon and evening development. Will go with just moderate to lower CHC pops in the afternoon and focus on the south half of the fcst area, but would not be surprised if most of the area stays dry in the afternoon through 00z Wed. High temps a challenge with debris possibly tempering warm up potential, but should still stay humid regardless of ambient temps. ..12.. .LONG TERM...(Tuesday Night through next Monday) ISSUED AT 339 PM CDT Mon Jul 11 2016 Forecast focus on severe weather potential through Wednesday night then quiet weather Thursday and Friday...but chance of storms return by the weekend. Tuesday night through Wednesday night: Periods of thunderstorms with the potential for all modes of severe weather and heavy rainfall. SPC has a slight risk for severe storms but this may be upgraded to a higher risk especially for Wednesday afternoon and evening. This is when the main upper level trough...deep layer shear is strong and a cold front arrives. Tornadoes cannot be ruled out. PWAT's will be over 2 inches which is in the 99th percentile and dewpoints in the mid to upper 70s which would support several inches of rain in a short time. This amount of rain would cause flash flooding. Thursday through Friday: Weak high pressure and a wnw flow aloft should bring a brief quiet and dry period. Friday will be the coolest day with highs in the mid 70s to around 80 and dewpoints in the lower 60s. Saturday through Monday: The active pattern quickly returns as the heat dome builds in the Plains and cooler weather exists around the Great Lakes region. This puts the dvn cwa in the ring of fire on the edge of the heat dome. Timing of individual waves that would trigger mcs activity is tricky this far out so the grids will have small pops each day for now. Heat and humidity will be increasing during this time frame. HAASE && .AVIATION...(For the 06Z TAFS through 06Z Tuesday Night) ISSUED AT 1153 PM CDT Mon Jul 11 2016 A linear complex of thunderstorms moving out of central IA will impact the terminals tonight with a brief period of gusty winds and possible IFR visibilities due to heavy rain. Current thinking is that storms will most likely weaken and settle south of the area by Tuesday morning, followed by a break during the day before thunderstorms redevelop Tuesday evening. There is the small potential that at last scattered storms could redevelop in the morning and also for possible MVFR cigs to linger longer than advertised. The next round of storms was handled with prob30 wording for Tue evening. In between, conditions should be VFR for most of the day with warm and humid conditions and south to southwest winds at the surface. && .DVN Watches/Warnings/Advisories... IA...None. IL...None. MO...None. && UPDATE...Sheets SYNOPSIS...12 SHORT TERM...12 LONG TERM...Haase AVIATION...Sheets
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 354 PM CDT MON JUL 11 2016 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-121100- 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- 354 PM CDT MON JUL 11 2016 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...THIS AFTERNOON AND TONIGHT HOT AND HUMID CONDITIONS WILL CONTINUE THROUGH EARLY EVENING...WITH HEAT INDEX READINGS IN THE 95 TO 100 DEGREE RANGE. LATER TONIGHT...THUNDERSTORMS ARE EXPECTED TO MOVE IN FROM THE WEST AND NORTHWEST MAINLY AFTER MIDNIGHT. THERE IS A LOW CHANCE THAT SOME OF THESE STORMS WILL BE ABLE TO PRODUCE STRONG WIND GUSTS NORTHWEST OF A LINE FROM IOWA CITY...TO CEDAR RAPIDS...TO DUBUQUE FROM MIDNIGHT THROUGH 3 AM CDT. OTHERWISE...AS THE STORMS OVERSPREAD THE REST OF THE OUTLOOK AREA THROUGH TUESDAY MORNING... THEY WILL WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY TUESDAY THROUGH WEDNESDAY...THERE IS A CHANCE OF THUNDERSTORMS. CURRENTLY...CONDITIONS APPEAR FAVORABLE FOR SOME SEVERE STORMS. THE RISK OF DAMAGING WINDS WOULD BE THE PRIMARY SEVERE WEATHER CONCERN. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE. FRIDAY NIGHT THROUGH SUNDAY...THERE IS A CHANCE OF THUNDERSTORMS. CONDITIONS ARE TOO UNCERTAIN TO ASSESS ANY SEVERE RISK AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT.
The Quad Cities radar (KDVN), 6 km away, was scanning. The volume nearest the first event began at 08:32 UTC.
1 thunderstorm wind. Local standard time, as filed.
A large, old tree fell onto three vehicles near Davenport Avenue and Kirkwood Boulevard during the early morning. A few utility lines were also knocked down by the tree. The time was estimated by radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2016Every state in 2016This day in weather historyWarnings in Iowa, July 2016
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: 652789.