A thunderstorm complex developed ahead of a disturbance that moved across eastern Iowa August 8th to the 9th and produced 3 to 5 inches of rain in the English River basin. This heavy rainfall produced flash flooding that eventually led to the English River near Kalona rising above its major flood stage on August 11th through the 12th.
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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 thunderstorm complex developed ahead of a disturbance that moved across eastern Iowa August 8th to the 9th and produced 3 to 5 inches of rain in the English River basin. This heavy rainfall produced flash flooding that eventually led to the English River near Kalona rising above its major flood stage on August 11th through the 12th.
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 11, 5:28 AM CST, 5 hours 13 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 628 AM CDT TUE AUG 11 2015 .SYNOPSIS... ISSUED AT 324 AM CDT TUE AUG 11 2015 QUIET WEATHER PREVAILED TONIGHT ACROSS THE REGION COURTESY OF A DRY NW FLOW ALOFT AND HIGH PRESSURE BUILDING INTO THE PLAINS. TEMPERATURES AT 3 AM WERE FROM AROUND 60 TO THE MID 60S WITH LIGHT NW WINDS. IR SATELLITE IMAGERY SHOWED A SCATTERED LOW TO MID LEVEL CLOUDS ASSOCIATED WITH A WEAK UPPER LEVEL IMPULSE OVER NORTHERN IL AND ALONG THE MS RIVER SOUTH OF I-80. OTHERWISE... SKIES WERE MAINLY CLEAR FROM THE WESTERN GREAT LAKES WEST INTO THE HIGH PLAINS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 324 AM CDT TUE AUG 11 2015 DRY AND MILD WEATHER WILL REMAIN IN PLACE TODAY THROUGH TONIGHT. TEMPERATURES ARE THE MAIN CHALLENGE...ALONG WITH THE POTENTIAL FOR PATCHY FOG LATE TONIGHT. THE DEVELOPING UPPER LEVEL BLOCKING PATTERN...FEATURING A LONGWAVE RIDGE OVER THE ROCKIES...WILL KEEP A DRY AND SUBSIDENT NW FLOW ALOFT OVER THE LOCAL AREA THROUGH TONIGHT. AT THE SURFACE...THE HIGH PRESSURE OVER NEB AND THE DAKOTAS EARLY THIS MORNING SPREADS EAST TO ROUGHLY FROM KS THROUGH CENTRAL IA TO SW WI BY 12Z WED. TODAY...SKIES SHOULD BE MOSTLY SUNNY WITH FAIR WEATHER CU DEVELOPING BY LATE MORNING...BASED ON THE WRF CU RULE AND LOOKING BACK AT SATELLITE IMAGES FROM YESTERDAY IN THE AIRMASS SOURCE REGION IN THE UPPER MS VALLEY. THIS TRAJECTORY ALSO SUPPORTS HIGHS IN THE LOWER 80S...CLOSE TO MODEL GUIDANCE AS WELL AS THE PREVIOUS FORECAST AND ONLY MINOR TWEAKS MADE. HUMIDITY LEVELS WILL BE AT MORE COMFORTABLE LEVELS COMPARED TO THE PAST FEW DAYS...AS SURFACE DEWPOINTS REMAIN IN THE UPPER 50S TO LOWER 60S. DAYTIME MIXING WILL RESULT IN N-NW WINDS MAXING OUT AROUND 10 TO 15 MPH. TONIGHT...DIURNAL CU WILL DISSIPATE EARLY FOR ANOTHER CLEAR NIGHT. THE WEAKER SURFACE PRESSURE GRADIENT AS THE RIDGE APPROACHES WILL PROVIDE ONLY LIGHT NORTH WINDS. THE POTENTIAL FOR FOG LOOKS GREATEST OVER THE FAR EAST AND NORTHEAST...WHERE MODEL LOW LEVEL RH AND PRESSURE FIELDS SUGGEST A WEAK BACKDOOR LAKE ENHANCED BOUNDARY MAY PROVIDE SUFFICIENT LOW LEVEL MOISTURE CONVERGENCE. FOR NOW...HAVE ADDED PATCHY FOG WORDING TOWARD SUNRISE OVER FAR NW IL INTO THE FAR NORTHERN MS RIVER VALLEY. ELSEWHERE...CURRENT INDICATIONS SUGGEST ONLY SHALLOW GROUND FOG DUE TO THE DRY AIRMASS. RADIATIONAL COOLING SHOULD LEAD TO LOWS RANGING FROM THE MID 50S IN THE COOLER CENTRAL AND NORTHERN VALLEYS TO THE LOWER 60S SOUTH. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 324 AM CDT TUE AUG 11 2015 WEDNESDAY AND THURSDAY...THE UPPER MISSISSIPPI VALLEY WILL BE ON THE WESTERN FLANK OF AN EAST COAST TROUGH. SFC-850MB HIGH PRESSURE RIDGING WILL RESULT IN PLEASANT MID AUGUST TEMPS IN THE LOWER TO MIDDLE 80S AND DRY CONDITIONS. SW WINDS ARE FORECAST TO BE STRONGER ON THURSDAY WITH GUSTS NEAR 20 MPH ACROSS THE NORTHERN THIRD OF THE CWA. POSITIVE 1000-500MB THICKNESS ADVECTION SIGNALS A WARMING TREND FOR THE COMING DAYS. FRIDAY...MID-LEVEL SHORTWAVE TROUGH CROSSING THROUGH THE GREAT LAKES COULD DRAG A SFC WIND SHIFT INTO E IOWA/W ILLINOIS BRINGING WITH IT A CHANCE FOR ISOLATED TO SCT CONVECTION. ECMWF IS MOSTLY DRY... BUILDING THE 850MB HIGH OVERHEAD....GFS IS A LITTLE WETTER. HAVE 20 TO 30 POPS OVER THE NORTHEAST ONE-HALF OF THE CWA. FORECASTS HIGHS ARE IN THE MID/UPPER 80S AND HUMIDITY WILL BE A LITTLE MORE NOTICEABLE AS DEWPOINTS CREEP BACK TO NEAR 70 F. SATURDAY AND SUNDAY...MODELS HAVE A BROAD SFC-850MB HIGH PUSHING SOUTHEASTWARD WITH TIME REACHING THE MID-ATLANTIC COAST BY LATE SUNDAY. NOT MUCH CHANGE IN THE FORECAST LOCALLY...MID TO UPPER 80S FOR HIGHS ON AVG WITH DRY CONDITIONS. MONDAY...APPROACHING COLD FRONT MEANS AT LEAST A SLIGHT CHANCE FOR RAIN. SINCE SFC LOW IS WELL UP INTO CANADA...NEAR THE HUDSON BAY...ASSOCIATED DYNAMICS APPEAR WEAK. CURRENT FORECAST IS GOING WITH 20-40 POPS SUN NIGHT THROUGH MONDAY...HIGHEST IN THE NW SECTION OF THE CWA. FORECAST HIGHS ARE FROM LOWER 80S NORTH/UPPER 80S SOUTH. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 628 AM CDT TUE AUG 11 2015 HIGH PRESSURE MOVING INTO THE REGION WILL PROVIDE VFR CONDITIONS THROUGHOUT WITH LIGHT NORTH TO NORTHWEST WINDS. THERE IS A LOW POTENTIAL FOR GROUND FOG EARLY WEDNESDAY MORNING...WHICH WAS NOT INCLUDED IN THE CURRENT FORECASTS. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && SYNOPSIS...SHEETS SHORT TERM...SHEETS LONG TERM...UTTECH AVIATION...SHEETS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 407 AM CDT TUE AUG 11 2015 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-120915- 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- 407 AM CDT TUE AUG 11 2015 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 NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. SHEETS
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
The English River at Kalona rose above the major flood stage of 18 feet during the morning hours of August 11th and fell below 18 feet shortly before 3 AM on August 12. The river recorded a preliminary crest of 18.48 ft on the 11th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2015Every state in 2015This day in weather historyWarnings in Iowa, August 2015
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: 597607.