A warm and humid air mass remained in place across eastern Iowa during the afternoon and early evening of August 29, 2016. Scattered showers and thunderstorms developed during the afternoon with one thunderstorm producing winds that belw down a healthy tree near DeWitt in Clinton County.
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.
A warm and humid air mass remained in place across eastern Iowa during the afternoon and early evening of August 29, 2016. Scattered showers and thunderstorms developed during the afternoon with one thunderstorm producing winds that belw down a healthy tree near DeWitt in Clinton 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 29, 2:13 PM CST, 24 minutes earlier.
Area Forecast Discussion National Weather Service Quad Cities IA IL 313 PM CDT MON AUG 29 2016 .SYNOPSIS... Issued at 300 PM CDT Mon Aug 29 2016 18Z surface data has high pressure over the Great Lakes while a cold front ran from northern Minnesota into northwest Nebraska. Dew points were in the 60s and 70s from the Ohio Valley into the Plains with 40s and 50s across the northern Plains. && .SHORT TERM...(This Evening through Tuesday) ISSUED AT 300 PM CDT Mon Aug 29 2016 Isolated to scattered convection will persist through late afternoon. Due to the slow movement of the storms, locally heavy rainfall is likely from the stronger storms. If these storms move across areas that were hit with heavy rain last night, then localized flooding will be possible. The convection will persist into the evening hours and the threat of locally heavy rainfall will continue through midnight. As the sun sets, the showers and thunderstorms will slowly weaken. After midnight, the showers and thunderstorms will continue to decrease in areal coverage. At the same time patchy fog will begin to develop due to light winds and high moisture levels in the lower atmosphere. Although not certain, the possibility does exist for the fog to become locally dense toward morning. Tuesday, the cold front is forecast to move through the area. Patchy fog will be possible shortly after sunrise but should dissipate by mid-morning. Isolated to scattered showers and some thunderstorms will slowly increase in areal coverage during the late morning and afternoon hours. As new convection develops Tuesday afternoon, the possibility will again exist for brief funnel clouds. The funnels will be most likely during the initial updraft development of the new convection. .LONG TERM...(Tuesday Night through Monday) ISSUED AT 300 PM CDT Mon Aug 29 2016 Tuesday Night and Wednesday...Scattered showers and storms are possible at least through Wednesday morning before a cold front finally pushes south into Missouri and southern Illinois. Weak 0-6 km shear of less than 25 kts and PWATs near or exceeding 1.75" are conducive for slow moving storms capable of producing 1-2"/hr rain rates, thereby posing a localized flash flood threat. Rain coverage and timing: Since areal coverage should stay isolated to scattered, there will likely be many areas that receive little to no rainfall. The higher chances for rain by Wednesday morning into the early afternoon are to the south of I-80 ahead of the sfc front. Wednesday Night through Saturday...Large Canadian high pressure forecast to cross through Manitoba into Ontario and the Great Lakes region. For E Iowa/NW Illinois, northeasterly winds will advect in much drier air. Expect comfortable humidity levels for a change and nice late summer/early fall weather - highs in the 70s/lows in the 50s. Saturday Night through Monday...Sfc winds respond to increasing pressure gradient over the Midwest by increasing out of the south. This will be the first sign of a pattern change to more humid conditions and chances for showers and storms. Although, chances are fairly low until Monday when a cold front approaches from the west. Forecast highs are in the 80s, dewpoints are well into the 60s or low 70s. Uttech && .AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon) ISSUED AT 1237 PM CDT Mon Aug 29 2016 VFR conditions should be seen through 03z/30 but pockets of MVFR conditions will be possible from diurnal clouds. If a TSRA affects a TAF site then a period of MVFR/IFR conditions will be possible. After 03z/30 conditions will slowly deteriorate to MVFR as patchy fog develops across eastern Iowa/northern Illinois. The possibility does exist for pockets of IFR/LIFR conditions prior to sunrise Tuesday. After sunrise Tuesday, conditions will slowly improve back to VFR. && .HYDROLOGY... Issued at 300 PM CDT Mon Aug 29 2016 Flood Warnings: Steady river level rises the past several days have increased confidence in reaching minor flood stage at three sites. Flood Watches were upgraded to Flood Warnings at Conesville on the Cedar River, and at Gladstone and Burlington on the Mississippi River. Flood Watches: Lower confidence exists for other sites where the forecast to reach minor flood stage is beyond 24 hours. Continued the Flood Watch for Keithsburg and issued a new Flood Watch for New Boston LD17, both on the Mississippi River. On the Wapsipinicon River, decided not to issue a watch for Dewitt because we are anticipating a river level fall to occur before the rise that may bring it to minor flood stage toward the end of this week. Uttech && .DVN Watches/Warnings/Advisories... IA...None. IL...None. MO...None. && SYNOPSIS...08 SHORT TERM...08 LONG TERM...Uttech AVIATION...08 HYDROLOGY...Uttech
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 406 AM CDT MON AUG 29 2016 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-300915- 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- 406 AM CDT MON AUG 29 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 SCATTERED THUNDERSTORMS ARE POSSIBLE ACROSS THE OUTLOOK AREA TODAY AND TONIGHT. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAINFALL...WHICH MAY LEAD TO LOCALIZED FLASH FLOODING. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY SCATTERED THUNDERSTORMS ARE POSSIBLE ON TUESDAY AND WEDNESDAY ACROSS THE AREA. THE MAIN THREAT FROM THESE STORMS WOULD BE HEAVY RAINFALL AND LIGHTNING. AT THIS TIME SEVERE WEATHER IS NOT EXPECTED. RISES ON SEVERAL AREA RIVERS WILL CONTINUE THIS WEEK. MINOR FLOODING IS POSSIBLE ON PORTIONS OF THE CEDAR AND WAPSIPINICON RIVERS...AS WELL AS THE MISSISSIPPI DOWNSTREAM OF NEW BOSTON. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT TODAY OR TONIGHT. HOWEVER...REPORTS OF HEAVY RAINFALL OR FLASH FLOODING WILL BE APPRECIATED. SHEETS/GIBBS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE QUAD CITIES IA IL 247 PM CDT MON AUG 29 2016 IAZ052-053-292100- LINN-JONES- INCLUDING THE CITIES OF...CEDAR RAPIDS...ANAMOSA 247 PM CDT MON AUG 29 2016 ...SLOW MOVING THUNDERSTORMS... AT 240 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THUNDERSTORMS NEAR WALKER...TROY MILLS AND COGGON IN LINN COUNTY...AND NEAR CENTER JUNCTION IN JONES COUNTY. THESE STORMS WERE DRIFTING SLOWLY EASTWARD...AND WILL BRING TORRENTIAL RAIN WITH LOCALIZED AMOUNTS OF 1 TO 3 INCHES LIKELY. THIS AMOUNT OF HEAVY RAIN WILL PRODUCE PONDING OF WATER ON ROADWAYS AND LEAD TO MINOR FLOODING OF DITCHES AND OTHER POORLY DRAINED AREAS...WITH RISES ON SMALL STREAMS AND CREEKS POSSIBLE. IF YOU ENCOUNTER WATER OVER A ROADWAY...DO NOT DRIVE INTO IT. IN ADDITION TO THE HEAVY RAIN...VISIBILITIES WILL BE GREATLY REDUCED. THE STRONGEST STORMS MAY ALSO BE CAPABLE OF PRODUCING GUSTY WINDS OF 30 TO 40 MPH AND HAIL UP TO NICKEL SIZE.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
248 PM CDT MON AUG 29 2016
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0247 PM HEAVY RAIN SSE WALKER 42.28N 91.78W
08/29/2016 M2.50 INCH LINN IA TRAINED SPOTTER
TOTAL SINCE 1 PM.
&&
DCSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA/IL
256 PM CDT MON AUG 29 2016
ILC073-131-292130-
HENRY-MERCER-
256 PM CDT MON AUG 29 2016
...AN AREA OF THUNDERSTORMS WITH TORRENTIAL RAINS WILL AFFECT
SOUTHWESTERN HENRY AND SOUTHEASTERN MERCER COUNTIES UNTIL 430 PM
CDT...
AT 253 PM CDT...THUNDERSTORMS WITH VERY HEAVY RAINS WERE CLUSTERED
ACROSS THE SOUTHEAST HALF OF MERCER COUNTY...MOVING NORTHEAST AT 5
MPH.
LOCATIONS IMPACTED INCLUDE...
BURGESS...VIOLA...WOODHULL...ALPHA...SEATON...NORTH HENDERSON...NEW
WINDSOR...ALEXIS...OPHIEM...GRIFFIN...GILCHRIST AND SUNBEAM.
TORRENTIAL RAINFALL IS OCCURRING WITH THESE STORMS...AND MAY CAUSE
LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.
LAT...LON 4115 9044 4107 9044 4106 9047 4107 9077
4111 9089 4130 9037 4115 9026
TIME...MOT...LOC 1953Z 230DEG 6KT 4114 9055
BROOKSSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE QUAD CITIES IA/IL 311 PM CDT MON AUG 29 2016 ILC195-292145- WHITESIDE- 311 PM CDT MON AUG 29 2016 ...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT EAST CENTRAL WHITESIDE COUNTY UNTIL 445 PM CDT... AT 309 PM CDT...STRONG THUNDERSTORMS WERE CLUSTERED OVER EAST CENTRAL WHITESIDE COUNTY, OVER ROCK FALLS AND COMO. THE STORMS ARE NEARLY STATIONARY. LOCATIONS IMPACTED INCLUDE... STERLING...ROCK FALLS...AGNEW...YEOWARD ADDITION...DOUGLAS PARK... GALT...WHITESIDE COUNTY AIRPORT...GRIMES ADDITION AND COMO. THIS INCLUDES INTERSTATE 88 BETWEEN MILE MARKERS 34 AND 44. TORRENTIAL RAINFALL IS OCCURRING WITH THIS STORM...AND MAY CAUSE LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS. LAT...LON 4165 8973 4178 8984 4183 8963 4166 8963 TIME...MOT...LOC 2009Z 150DEG 1KT 4173 8969 BROOKS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE QUAD CITIES IA/IL 317 PM CDT MON AUG 29 2016 IAC045-163-292045- CLINTON-SCOTT- 317 PM CDT MON AUG 29 2016 ...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL CLINTON AND NORTH CENTRAL SCOTT COUNTIES UNTIL 345 PM CDT... AT 316 PM CDT...A STRONG THUNDERSTORM WAS LOCATED NEAR LONG GROVE...OR 12 MILES NORTH OF DAVENPORT...MOVING NORTH AT 40 MPH. WINDS IN EXCESS OF 40 MPH AND SMALL HAIL IS LIKELY WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... ELDRIDGE...DEWITT...LONG GROVE...GRAND MOUND...DONAHUE...WELTON... PARK VIEW...SCOTT COUNTY PARK AND CLINTON COUNTY FAIRGROUNDS. TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY CAUSE LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS. FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. LIGHTNING CAN STRIKE 10 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE SHELTER INSIDE A BUILDING OR VEHICLE. LAT...LON 4163 9056 4166 9072 4193 9070 4192 9045 TIME...MOT...LOC 2016Z 190DEG 35KT 4174 9061 05
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
318 PM CDT MON AUG 29 2016
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0316 PM HAIL ELDRIDGE 41.64N 90.57W
08/29/2016 M0.50 INCH SCOTT IA NWS EMPLOYEE
OCCASIONAL PIECES OF HALF INCH HAIL
&&
DCThe Quad Cities radar (KDVN), 17 km away, was scanning. The volume nearest the first event began at 20:34 UTC.
1 thunderstorm wind. Local standard time, as filed.
A COOP Observer that a healthy tree was blown down at their residence during a thunderstorm. 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: 658068.