A warm and humid air mass was in place across eastern Iowa during the afternoon of August 19th. Isolated showers and thunderstorms developed in the afternoon north of Interstate 80.
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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 DVN wrote it up.
A warm and humid air mass was in place across eastern Iowa during the afternoon of August 19th. Isolated showers and thunderstorms developed in the afternoon north of Interstate 80. One of these thunderstorms briefly intensified and produced nickel sized hail and brief wind gusts up to 50 mph as it moved across Jones 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 Quad Cities, IA wrote its last area forecast discussion before the first event at Aug 19, 11:45 AM CST, 2 hours earlier.
Area Forecast Discussion National Weather Service Quad Cities IA IL 1245 PM CDT FRI AUG 19 2016 .UPDATE... Issued at 1239 PM CDT Fri Aug 19 2016 Trends the past hour with the central Iowa convection suggests that it should follow the instability gradient through early afternoon. At that point the convection will intersect the outflow boundary from the nocturnal storms and may turn more to the southeast. Differential heating may also allow isolated convection to develop across the area during max heating. && .SYNOPSIS... Issued at 307 AM CDT Fri Aug 19 2016 Active and wet pattern continues with quasi-zonal flow aloft. Water vapor satellite shows next wave of interest dropping into western Montana this morning. At the surface, slow moving cold front extends from the upper peninsula of Michigan across western Iowa and into western Kansas. MCS has tracked south out of the area, continuing to follow the CAPE gradient across central Illinois. Elevated convection that initially triggered on the MCS outflow boundary continues to move slowly east across Carroll County, fortunately north of where the heavier rain fell earlier in Whiteside County. && .SHORT TERM...(Today and Tonight) ISSUED AT 307 AM CDT Fri Aug 19 2016 Forecast focus is thunderstorm chances throughout the short term. Short range models are of little use this morning as they have not been handling the track or evolution of the ongoing convection. With boundaries lingering over area and without a cap, expect lingering isolated to scattered convection to fester today. Have introduced low precip chances for the northern half of the forecast area. By evening, there is a possibility for a more focused area of storms as the upper level energy and surface cold front approach. By tonight, widespread thunderstorms are expected as the main energy drops into the base of the trough over the plains and the whole system begins to move out. There is some concern for severe wind depending on the timing of the line as instability will be adequate and low level lapse rates could support strong winds in surface- based storms near the front. Temperature forecasts today are also somewhat problematic. With increased cloud cover expected, have shaved a few degrees off of today's high temperatures. However, high temperatures may still be too warm in some areas where the clouds stick. .LONG TERM...(Saturday through Thursday) ISSUED AT 307 AM CDT Fri Aug 19 2016 Seasonably strong cold front will bring much cooler conditions with a hint of fall by late in the weekend into early next week. Strong dynamics aided by anomalously deep upper trough and divergence with entrance region of jet, along with DCVA in concert with frontal convergence will lead to widespread showers and some storms Saturday morning tapering off during the day from west to east. Still appears to be some substantial differences with deterministic models on strength and placement of surface low on Saturday. NAM and GEM appear to be unrealistic strong outliers on strength of closed surface low with a more fall-type cyclogenesis and intensification, not supported by the upper jet structure, as the system lifts from the MN/WI/IA border region on Saturday. Some re-intensification of storms is possible by afternoon mainly eastern cwa ahead of the cold front with bulk shear 0-6km of 30+ kts, but a conditional risk of strong to possibly isolated severe storms dependent on amount of heating/destabilization. In the wake of the front, a much cooler airmass will settle in for the latter half of the weekend through Monday with below normal temperatures and lower humidity making for quite pleasant late summer weather. Some models show 850 mb temperatures as low as 10C, which if occurs with strong inversion would be supportive of some lows in the 40s possibly by Monday morning. Tuesday through Thursday, an upper level wave and return of low to mid level warm, moist air will lead to near normal temperatures (around 80/lower 80s for highs) and increasing rain chances into Thursday. May then see another decent cold front with a return of dry and cool conditions yet again late next week into the weekend. && .AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon) ISSUED AT 1239 PM CDT Fri Aug 19 2016 Mainly VFR conditions with pockets of MVFR will be seen through 06z/20. Convection in central Iowa should move generally east but should slowly turn more to the southeast following the best instability. KCID has the best chance of being affected by this convection with lesser chances at KDBQ/KMLI. After 06z/20 conditions will slowly deteriorate to MVFR as widespread convection develops along the approaching cold front. Brief IFR conditions will be possible in the stronger storms. && .DVN Watches/Warnings/Advisories... IA...NONE. IL...NONE. MO...NONE. && UPDATE...08 SYNOPSIS...DMD SHORT TERM...DMD LONG TERM...MWM AVIATION...08
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 400 AM CDT FRI AUG 19 2016 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-200900- 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- 400 AM CDT FRI AUG 19 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...TODAY AND TONIGHT THIS MORNING...ISOLATED THUNDERSTORMS WILL BE POSSIBLE. THE MAIN THREAT THIS MORNING WILL BE FROM LIGHTNING...AS THESE STORMS ARE NOT EXPECTED TO REACH SEVERE LEVELS. THIS AFTERNOON AND TONIGHT...THUNDERSTORMS ARE EXPECTED TO BECOME MORE WIDESPREAD AND SOME MAY BECOME STRONG TO SEVERE. IN ADDITION TO LIGHTNING...SOME STORMS COULD PRODUCE DAMAGING WIND. LATE TONIGHT AND INTO SATURDAY MORNING...A LINE OF STORMS IS EXPECTED TO CROSS THE AREA AS THE MAIN COLD FRONT APPROACHES. THE MAIN THREATS OVERNIGHT WILL BE STRONG TO DAMAGING WIND AND FREQUENT LIGHTNING. ASIDE FROM THE THUNDERSTORMS...HOT AND HUMID CONDITIONS WILL BE FOUND AGAIN TODAY WITH AFTERNOON HEAT INDICES IN THE 90S. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY STORMS WILL PERSIST SATURDAY MORNING. SOME INTENSIFICATION COULD RESULT IN A FEW STRONG TO ISOLATED SEVERE STORMS BY SATURDAY AFTERNOON, MAINLY EAST OF THE MISSISSIPPI RIVER. THIS POTENTIAL HOWEVER, WILL BE LARGELY DEPENDENT ON THE AMOUNT OF INSTABILITY. TUESDAY NIGHT THROUGH WEDNESDAY WILL BRING THE NEXT CHANCE OF THUNDERSTORMS. AT THIS TIME...IT IS TOO EARLY TO DETERMINE THE RISK FOR SEVERE WEATHER. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON THROUGH TONIGHT.
The Quad Cities radar (KDVN), 81 km away, was scanning. The volume nearest the first event began at 19:45 UTC.
1 hail. Local standard time, as filed.
Law Enforcement reported nickel sized hail and estimated wind speeds of 50 mph. Time of the event was estimated using 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, August 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: 658067.