A cluster of storms that developed in Nebraska near a parent low pressure system the night before progressed eastward through the overnight and morning hours, eventually making its way across northern Iowa. Storm development ahead of the cluster remained sub-severe throughout the day, and some strengthening occurred during the early afternoon hours with a severe report made for damaging winds in…
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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.
A cluster of storms that developed in Nebraska near a parent low pressure system the night before progressed eastward through the overnight and morning hours, eventually making its way across northern Iowa. Storm development ahead of the cluster remained sub-severe throughout the day, and some strengthening occurred during the early afternoon hours with a severe report made for damaging winds in Waterloo.
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 Jul 23, 11:40 AM CST, 2 hours earlier.
Area Forecast Discussion National Weather Service Des Moines IA 1240 PM CDT Sat Jul 23 2016 .SHORT TERM.../Today/ Issued at 340 AM CDT Sat Jul 23 2016 A large complex of showers and thunderstorms has been progressing slowly eastward across Nebraska overnight and is nearing the Missouri River valley. Ahead of this complex isolated showers and storms have developed across Iowa as anticipated. Most global models are not handling the Nebraska convection well, if they recognize it at all, but some of the high-resolution short-term models like the HRRR have a much better handle on it and continue to move it eastward, albeit with decreasing intensity, across our area through the morning hours to around midday. Have trended this way with a significant increase of POPs this morning, especially in our western and northwestern counties, as well as a lowering of temperatures to account for rain and cloud effects. This leaves the excessive heat warning looking a bit marginal, however with it being the fourth day of the event and with some warming expected yet this afternoon and evening, and a continuation of very high humidity, will leave the headline as is given that heat index values should still peak above 100 degrees. Later today, after the morning rainfall, uncertainty increases regarding the potential development of additional thunderstorms toward this evening. SPC has maintained a slight risk of severe weather across northern Iowa around this evening/tonight but it will be conditional on how the airmass recovers and where boundaries lie after the morning storms roll through. .LONG TERM.../Tonight through Friday/ Issued at 340 AM CDT Sat Jul 23 2016 Couple of challenges in the near term including continued thunder chances and temperatures. Tonight convection developing across the high plains will track across MN and Wisconsin with trailing thunderstorms developing into northern Iowa. With the main band of westerlies setting up north of us the balance of the stronger storms should remain over MN but there may be some entering northern Iowa late this evening. Over the rest of the area as the trough swings southwest a few isolated thunderstorms may develop along the wind shift though convergence will be rather meager with winds nearly parallel to the boundary...some isentropic lift over the boundary will also result in small chances for elevated convection in southern Iowa Sunday morning and spreading back farther north during the afternoon hours to near I80. The overall severe threat will drop by Sunday with only general thunder anticipated. Lows tonight will continue very warm with mid 70s south and upper 60s far north. Sunday H850 temperatures linger in the 20 to 25C range south. Despite weak northwest flow aloft and chances for convection highs will still push the 90 mark south of I80 with mid 80s over the far north. Cooler and drier air arrives by Sunday night northwest with lows falling into the lower 60s. Across the south mid to upper 60s will linger until Monday night. On Monday pleasant weather returns with high pressure in charge through Tuesday morning. As the high recedes into the Great Lakes return flow along with increased isentropic lift will result in increasing thunder chances west Tuesday afternoon and regionwide Tuesday night into Wednesday. Confidence in the extended begins to deteriorate as mesoscale processes begin to dominate the pattern through the end of the period. Generally...the frontal boundary dropping south tonight will linger over the mid Mississippi River Valley with short wave energy approaching from the northwest Tues night/Wed and again late Thursday into Friday. Though the models dont completely dry things out on Thursday...chances for thunder should drop between systems with the Tues night/Wed and Friday periods most likely being the preferred timeframe for more generous coverage. Highs cool to near seasonal normals in the mid 80s for highs and in the mid to upper 60s for lows. && .AVIATION.../For the 18Z TAFS through 18Z Sunday afternoon/ Issued at 1240 PM CDT Sat Jul 23 2016 Scattered showers and thunderstorms moving across Central Iowa this afternoon. The line may strengthen over Eastern Iowa mid to late afternoon. A few storms possible overnight though best potential is north into Minnesota. Breezy south winds today becoming northwest Sunday. && .DMX WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 7 PM CDT this evening for Adair- Adams-Appanoose-Audubon-Boone-Carroll-Cass-Clarke-Crawford- Dallas-Davis-Decatur-Greene-Guthrie-Jasper-Lucas-Madison-Mahaska- Marion-Marshall-Monroe-Polk-Poweshiek-Ringgold-Story-Tama-Taylor- Union-Wapello-Warren-Wayne. && SHORT TERM...Lee LONG TERM...REV AVIATION...Donavon
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 452 AM CDT SAT JUL 23 2016 IAZ044>050-057>062-070>075-081>086-092>097-241000- 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- 452 AM CDT SAT JUL 23 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT AN EXCESSIVE HEAT WARNING REMAINS IS IN EFFECT. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT NORTH OF HIGHWAY 30. DAMAGING WIND GUSTS AND LARGE HAIL WILL BE THE MAIN SEVERE THREATS...AND AN ISOLATED TORNADO CANNOT BE RULED OUT. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE. ELSEWHERE THERE IS A MARGINAL RISK OF A SEVERE THUNDERSTORM TODAY AND TONIGHT. DAMAGING THUNDERSTORM WINDS AND LOCALLY HEAVY RAINFALL ARE POSSIBLE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THUNDERSTORM CHANCES RETURN LATE TUESDAY INTO EARLY THURSDAY AND AGAIN ON FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY OR TONIGHT NORTH OF HIGHWAY 30. IAZ004>007-015>017-023>028-033>039-241000- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN- WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK- 452 AM CDT SAT JUL 23 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT NORTH OF HIGHWAY 30. DAMAGING WINDS GUSTS AND LARGE HAIL WILL BE THE MAIN SEVERE THREATS...AND AN ISOLATED TORNADO CANNOT BE RULED OUT. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THUNDERSTORM CHANCES RETURN LATE TUESDAY INTO EARLY THURSDAY AND AGAIN ON FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY OR TONIGHT. REV
The Des Moines radar (KDMX), 142 km away, was scanning. The volume nearest the first event began at 19:37 UTC.
1 thunderstorm wind. Local standard time, as filed.
Trained spotter reported several tree branches down in the vicinity, up to 4 inches in diameter. Delayed report and time radar estimated.
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: 641294.