A small complex of thunderstorms traveled northeast through Kansas and Nebraska overnight the 22nd into the 23rd, finally arriving early in the afternoon. With instability building with daytime heating, the storms were able to strengthen and grow in spatial coverage as they traversed northwest/northern Iowa.
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.
A small complex of thunderstorms traveled northeast through Kansas and Nebraska overnight the 22nd into the 23rd, finally arriving early in the afternoon. With instability building with daytime heating, the storms were able to strengthen and grow in spatial coverage as they traversed northwest/northern Iowa. While no severe reports were made with the initial storms, heavy rainfall was reported. Later in the day, as a cold front approached, more storms were able to initiate and provide additional heavy rainfall as well as a couple of damaging wind reports. Most reports resided across northern Iowa, while the damaging winds occurred during the evening more towards southern Iowa.
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 Aug 23, 1:58 PM CST, 39 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 258 PM CDT Tue Aug 23 2016 .SHORT TERM.../Tonight into Wednesday/ Issued at 258 PM CDT Tue Aug 23 2016 Concerns center around chance of precipitation, amount of precipitation and chances for severe weather for this evening into the overnight hours. MCV that has been ongoing all day has pushed into NW IA from central NE this afternoon. Storms along the southern portion of the line have intensified in the past hour or so and expect further intensification as it moves ENE into north central Iowa late this afternoon. MUCAPE values around 2-3K J/KG with much of the CWA becoming uncapped in the next hour of so. Southerly flow continues to pump moisture northward and seeing some surface convergence in the wind field back to the west across ERN NE with stronger deep moisture convergence in the SPC Mesoanalysis data. Therefore expect majority of the activity through early evening to be across the north, with additional development pushing into the CWA toward this evening with peak heating and as the LLJ kicks in later tonight and spread activity across the entire CWA. Shear still on the lower end of the severe spectrum, however amount of instability should still warrant decent chance for stronger storms especially the threat of damaging winds. Heavy rain threat still exists, although the widespread threat has dwindled some and has shifted mainly to the northern CWA with this activity expected this afternoon and possibility of additional storms this evening. Greater chance of training storms this evening as storm motion expected to be more west to east with backbuilding possible as storms form along the nose of the LLJ. Have already had rain rates of 2-3 inches in an hour or less with these afternoon storms upstream and expect similar conditions into the evening. Will refrain from any flash flood watch however at this time as evening rainfall could end up being further south than the heavier rain this afternoon. Storms to linger into the late night hours and should exit the CWA toward early/mid Wednesday morning. Frontal boundary to stall across the south with additional development possible across the southern CWA Wednesday afternoon. .LONG TERM.../Wednesday Night through Tuesday/ Issued at 258 PM CDT Tue Aug 23 2016 |The synoptic H300 CONUS weather pattern will vary little over the next week with blocking high pressure over the southeast US and a subsequent upstream trough over the western states. This will place Iowa in broad southwest to westerly flow through the period with periodic chances of storms. Models are in good agreement on the placement of the surface boundary across south central and southeastern Iowa at the onset of the period Wednesday night. Heavy rainfall will be the primary threat through the overnight hours with ample moisture pooling along the boundary with PWATS around 1.9 to 2.0 inches and warm cloud depths of 12-13 kft. With the 500 mb flow parallel to the boundary orientation, cell training is somewhat of a concern. However, uncertainty lies in the coverage of storms along the front with little in the way of linear frontogenetical forcing. This may result in storms being more scattered in coverage and tied H500 vort max that is progged to move through during the 00-12Z Thu timeframe. The boundary will only slowly drift southward through the day on Thursday owing to the lack of upper level support. This southward push will be aided by a weak area of high pressure that will be centered over the CWA Friday morning. A 400mb PV anomaly currently discernible on water vapor imagery near Yakutat, AK, will progress southeastward over the course of the week and eject eastward over the Northern Plains Friday and Saturday. The nearly stationary front over the lower Missouri River valley will lift back northward into Iowa early Saturday in response to lee cyclogenesis over the High Plains and bring with it the chance for showers and thunderstorms for much of the weekend. POP model confidence wanes into the weekend given the weak flow pattern and nebulous nature of the upper level disturbances. Temperatures for the extended should be near seasonal norms given then somewhat zonal flow pattern. && .AVIATION.../For the 12Z TAFS through 12Z Wednesday morning/ Issued at 258 PM CDT Tue Aug 23 2016 Thunderstorm chances at all TAF sites through the evening into the overnight hours. Low MVFR/IFR CIGS expected late tonight into early Wednesday. Southerly winds to become more northwesterly later Wednesday. && .DMX WATCHES/WARNINGS/ADVISORIES...None. && SHORT TERM...Beerends LONG TERM...Skow AVIATION...Beerends
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 452 AM CDT TUE AUG 23 2016 IAZ033-044-045-057-058-070-071-081-082-092-093-241200- SAC-CRAWFORD-CARROLL-AUDUBON-GUTHRIE-CASS-ADAIR-ADAMS-UNION- TAYLOR-RINGGOLD- 452 AM CDT TUE AUG 23 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS WILL DEVELOP ACROSS THE OUTLOOK AREA THIS AFTERNOON AND BECOME WIDESPREAD TONIGHT. THERE IS A SLIGHT RISK FOR SEVERE STORMS WITH HAIL AND DAMAGING WIND THE MAIN THREATS. AN ISOLATED TORNADO IS POSSIBLE DURING THE LATE AFTERNOON AND EVENING HOURS. HEAVY RAINFALL AND THE POTENTIAL FOR FLOODING IS POSSIBLE WITH STORMS TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORM CHANCES REMAIN IN THE FORECAST ACROSS AREAS SOUTH OF INTERSTATE 80 WEDNESDAY AND ACROSS THE ENTIRE AREA FRIDAY NIGHT THROUGH THE WEEKEND. A FEW SEVERE STORMS AND THE THREAT FOR HEAVY RAINFALL ARE POSSIBLE FAR SOUTH ON WEDNESDAY. THE SEVERE AND HEAVY RAIN THREATS FOR STORMS LATER IN THE WEEK THROUGH THE WEEKEND WILL BE BETTER DETERMINED IN LATER FORECASTS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING AND AGAIN ON WEDNESDAY AFTERNOON. IAZ004>007-015>017-023>028-034>039-046>050-059>062-072>075- 083>086-094>097-241200- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-CALHOUN-WEBSTER- HAMILTON-HARDIN-GRUNDY-BLACK HAWK-GREENE-BOONE-STORY-MARSHALL- TAMA-DALLAS-POLK-JASPER-POWESHIEK-MADISON-WARREN-MARION-MAHASKA- CLARKE-LUCAS-MONROE-WAPELLO-DECATUR-WAYNE-APPANOOSE-DAVIS- 452 AM CDT TUE AUG 23 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT THERE IS A CHANCE FOR THUNDERSTORMS ACROSS THE OUTLOOK AREA THIS AFTERNOON WITH WIDESPREAD THUNDERSTORMS TONIGHT. THERE IS A SLIGHT RISK FOR SEVERE STORMS FOR LOCATIONS WEST OF INTERSTATE 35 AND SOUTH OF HIGHWAY 18 WITH A MARGINAL RISK ELSEWHERE. LARGE HAIL AND DAMAGING WIND WILL BE THE MAIN THREAT THROUGH THE EVENING HOURS. HEAVY RAINFALL AND THE POTENTIAL FOR FLOODING IS POSSIBLE WITH STORMS TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORM CHANCES REMAIN IN THE FORECAST ACROSS AREAS SOUTH OF INTERSTATE 80 WEDNESDAY AND ACROSS THE ENTIRE AREA FRIDAY NIGHT THROUGH THE WEEKEND. A FEW SEVERE STORMS AND THE THREAT FOR HEAVY RAINFALL ARE POSSIBLE FAR SOUTH ON WEDNESDAY. THE SEVERE AND HEAVY RAIN THREATS FOR STORMS LATER IN THE WEEK THROUGH THE WEEKEND WILL BE BETTER DETERMINED IN LATER FORECASTS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING AND AGAIN ON WEDNESDAY. FAB
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
249 PM CDT TUE AUG 23 2016
IAZ033-232030-
SAC IA-
249 PM CDT TUE AUG 23 2016
...STRONG GUSTY WINDS WITH STORM MOVING INTO NORTHERN SAC COUNTY...
AT 247 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM OVER
GALVA...OR 11 MILES NORTH OF IDA GROVE...MOVING NORTHEAST AT 55 MPH.
WIND GUSTS OF 40 TO 50 MPH WILL BE POSSIBLE WITH THIS STORM.
LOCATIONS IMPACTED INCLUDE...
SCHALLER...EARLY AND NEMAHA.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.
THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO
STATIONS AND AVAILABLE TELEVISION STATIONS FOR ADDITIONAL INFORMATION
AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
&&
LAT...LON 4256 9539 4256 9492 4246 9492 4240 9532
4247 9532 4248 9539
TIME...MOT...LOC 1947Z 244DEG 49KT 4251 9543
SKOWSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
252 PM CDT TUE AUG 23 2016
IAZ004-015-232030-
EMMET IA-PALO ALTO IA-
252 PM CDT TUE AUG 23 2016
...STRONG WINDS WITH LINE OF STORMS MOVING INTO PALO ALTO AND SAC
COUNTIES...
AT 252 PM CDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM NEAR WEST OKOBOJI TO 6 MILES WEST OF SILVER
LAKE TO NEAR SIOUX RAPIDS. MOVEMENT WAS NORTHEAST AT 50 MPH.
WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THESE STORMS.
LOCATIONS IMPACTED INCLUDE...
ESTHERVILLE...EMMETSBURG...FIVE ISLAND LAKE...INGHAM LAKE...SILVER
LAKE...HIGH LAKE...RUSH LAKE...LOST ISLAND LAKE...SWAN LAKE...
GRAETTINGER...WEST BEND...RUTHVEN...RINGSTED...MALLARD...
WALLINGFORD...AYRSHIRE...GRUVER...CYLINDER...DOLLIVER AND CURLEW.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THESE STORMS...AND MAY
LEAD TO LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH
FLOODED ROADWAYS.
THESE STORMS MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO
STATIONS AND AVAILABLE TELEVISION STATIONS FOR ADDITIONAL INFORMATION
AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
&&
LAT...LON 4350 9463 4329 9444 4295 9445 4291 9485
4291 9492 4350 9491
TIME...MOT...LOC 1952Z 244DEG 42KT 4332 9526 4306 9502 4286 9509
SKOWSPECIAL WEATHER STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE DES MOINES IA
254 PM CDT TUE AUG 23 2016
IAZ004-015-232030-
EMMET IA-PALO ALTO IA-
254 PM CDT TUE AUG 23 2016
...STRONG WINDS WITH LINE OF STORMS MOVING INTO PALO ALTO AND EMMET
COUNTIES...
AT 252 PM CDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM NEAR WEST OKOBOJI TO 6 MILES WEST OF SILVER
LAKE TO NEAR SIOUX RAPIDS. MOVEMENT WAS NORTHEAST AT 50 MPH.
WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THESE STORMS.
LOCATIONS IMPACTED INCLUDE...
ESTHERVILLE...EMMETSBURG...FIVE ISLAND LAKE...INGHAM LAKE...SILVER
LAKE...HIGH LAKE...RUSH LAKE...LOST ISLAND LAKE...SWAN LAKE...
GRAETTINGER...WEST BEND...RUTHVEN...RINGSTED...MALLARD...
WALLINGFORD...AYRSHIRE...GRUVER...CYLINDER...DOLLIVER AND CURLEW.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THESE STORMS...AND MAY
LEAD TO LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH
FLOODED ROADWAYS.
THESE STORMS MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO
STATIONS AND AVAILABLE TELEVISION STATIONS FOR ADDITIONAL INFORMATION
AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
&&
LAT...LON 4350 9463 4329 9444 4295 9445 4291 9485
4291 9492 4350 9491
TIME...MOT...LOC 1952Z 244DEG 42KT 4332 9526 4306 9502 4286 9509
SKOWSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
328 PM CDT TUE AUG 23 2016
IAZ005-015-016-023>025-232130-
WRIGHT IA-PALO ALTO IA-HUMBOLDT IA-POCAHONTAS IA-KOSSUTH IA-
HANCOCK IA-
328 PM CDT TUE AUG 23 2016
...STRONG LINE OF STORMS MOVING INTO NORTH CENTRAL IOWA...
AT 327 PM CDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM SILVER LAKE TO 6 MILES NORTHEAST OF LAURENS TO
NEAR NEWELL. MOVEMENT WAS EAST AT 40 MPH.
NICKEL SIZE HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH
THESE STORMS.
LOCATIONS IMPACTED INCLUDE...
ALGONA...POCAHONTAS...DAKOTA CITY...HUMBOLDT...LAURENS...SILVER
LAKE...RUSH LAKE...WEST BEND...KANAWHA...ROLFE...WHITTEMORE...GILMORE
CITY...WESLEY...LIVERMORE...CORWITH...BODE...MALLARD...LU VERNE...
RENWICK AND THOR.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THESE STORMS...AND MAY
LEAD TO LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH
FLOODED ROADWAYS.
THESE STORMS MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO
STATIONS AND AVAILABLE TELEVISION STATIONS FOR ADDITIONAL INFORMATION
AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
&&
LAT...LON 4297 9373 4269 9398 4260 9492 4281 9491
4288 9484 4299 9492 4305 9491 4322 9394
TIME...MOT...LOC 2027Z 256DEG 34KT 4301 9487 4290 9474 4261 9506
SKOWThe Des Moines radar (KDMX), 150 km away, was scanning. The volume nearest the first event began at 20:35 UTC.
9 heavy rain, 2 thunderstorm wind, 1 flash flood. Local standard time, as filed.
Public reported storm total heavy rainfall of 3.10 inches. Times radar estimated, with duration around 1 hour.
Coop observer reported heavy rainfall of 1.44 inches between 3:45 and 5:00 pm.
Coop observer reported storm total heavy rainfall of 3.53 inches.
Coop observer reported storm total heavy rainfall of 4.55 inches. End time radar estimated.
Public reported storm total heavy rainfall of 3.2 inches. Ending time radar estimated.
Public reported heavy rainfall of 3.80 inches storm total so far.
KIMT TV recorded heavy rainfall of 1.71 inches storm total.
Trained spotter reported heavy rainfall of 3.88 inches since early Tue evening.
Public reported storm total heavy rainfall of 2.35 inches.
Law enforcement reported a 1 mile stretch along 390th street near the intersection of Grouse Ave and 390th St closed and blocked off due to water over the road. Time estimated by radar. Delayed report.
Trained spotter reported wind gusts of 50-60 mph.
Trained spotter reported several tree limbs upwards of 8 inches in diameter downed. Additionally, a hollowed out 15 to 20 inch diameter tree downed. Over 1 inch of rainfall reported in half an hour as well.
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: 655455, 655456, 655465, 655464, 655459, 655460, 655461, 655463, 655466, 655462, 655467, 655468.