Several rounds of scattered showers and thunderstorms developed ahead of a cold front that was slowly moving eastward across Iowa. Thunderstorms in Jackson and Scott Counties produced damaging winds estimated to be near 60 mph.
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.
Several rounds of scattered showers and thunderstorms developed ahead of a cold front that was slowly moving eastward across Iowa. Thunderstorms in Jackson and Scott Counties produced damaging winds estimated to be near 60 mph. A thunderstorm in Louisa County caused a fire at a machine shed from a lightning strike. Brief torrential downpours were reported with several of the storms.
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 17, 12:01 PM CST, 54 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 101 PM CDT MON AUG 17 2015 .UPDATE... ISSUED AT 100 PM CDT MON AUG 17 2015 CONVECTIVE TEMPERATURE IN THE LOWER TO MID 80S (SBCAPES 2000-2500 J/KG) AND NO CAP HAS ALLOWED ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP RAPIDLY ACROSS THE DVN CWA. SHEAR IS VERY WEAK AND THESE PULSE STORMS WILL DIE OUT JUST AS QUICKLY WHILE NEW ONES FORM. THERE IS A BROAD AREA OF LOW LEVEL MOISTURE TRANSPORT AND PWAT'S ARE ABOUT 1.4 INCHES. THE COLD FRONT WILL SLOWLY EDGE SOUTHEAST INTO THE CWA WHILE GRADUALLY WEAKENING AND THEN LIFTING BACK NORTHWARD AS A WARM FRONT TONIGHT. SEVERE WEATHER IS NOT EXPECTED BUT AN ISOLATED STRONG WIND GUST AND LOCALLY HEAVY RAINFALL IS LIKELY. && .SYNOPSIS... ISSUED AT 330 AM CDT MON AUG 17 2015 THE LATEST SFC ANALYSIS WAS INDICATING A NORTHEAST-TO-SOUTHWEST ORIENTED FRONTAL SYSTEM SAGGING SOUTHEASTWARD FROM THE NORTHERN GRT LKS...INTO NORTHEAST TO SOUTHWEST IA...SE NEB AND THEN WAVERING INTO WESTERN KS/SE CO. REGIONAL 88D LOOPS INDICATING PRECIP FIELDS RUNNING ALONG AND MAINLY POST FRONTAL. ALOFT...00Z UPPER AIR ANALYSIS AND THE CURRENT WATER VAPOR LOOP WERE INDICATING AN ELONGATED VORT COMPLEX GENERALLY ALOFT OF THE LLVL FRONTAL SYSTEM... A CUT-OFF VORT MAX SWIRLING OVER FAR SOUTHERN IL...AND ANOTHER VORT MAX ACRS THE NORTHEASTERN GRT BSN/CO. A BROAD UPPER TROF WAS CONTINUING TO DIG ACRS CENTRAL CANADA...THE NORTHERN ROCKIES AND HIGH PLAINS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT MON AUG 17 2015 TODAY...A RATHER CHALLENGING FCST TO TRY AND HAMMER OUT...AND WILL USE UPSTREAM MASS FIELDS AND THEIR POTENTIAL EVOLUTION TO GENERATE A GENERAL PICTURE. THE FIRST PROBLEM IS HOW FAR SOUTH THE UPSTREAM FRONT WILL SAG AND MAKE IT INTO THE AREA. IT SHOULD STALL ACRS THE NORTHWESTERN THIRD OF THE CWA BY LATE AFTERNOON BECOMING PARALLEL TO LEE SIDE DIGGING UPPER TROF STEERING FLOW. BETWEEN DEBRIS CLOUD COVER...POST-FRONTAL SHOWERS AND A FEW STORMS MAKING IT INTO THE NORTHWESTERN CWA IF EVEN IN A DECREASING FASHION...A RATHER LARGE TEMPERATURE DISCREPANCY MAY FORM FROM THE NORTHWESTERN CWA TO THE FAR EAST...MID/UPPER 70S TO POSSIBLY THE MID TO UPPER 80S. DIFFERENTIAL HEATING...LLVL CONVERGENCE AND BUILDING INSTABILITY WILL THEN BE THE FUEL FOR MIDDAY AND ESPECIALLY AFTERNOON THUNDERSTORM DEVELOPMENT JUST TO THE LEE OF THE FRONTAL SYSTEM. THE SOUTHERN IL VORT MAX IS EXPECTED TO BE DEFLECTED NORTHEASTWARD ACRS IND LATER TODAY AND NOT BE A FACTOR THIS FAR WEST...BUT SOME OF THE 00Z MODELS SUGGEST THE CO VORT COMPLEX WILL GET DRAWN UP ACRS NW MO AND INTO IA AND MELD WITH ONGOING VORT ENHANCEMENT OCCURRING ACRS THE STATE FOR AN INCREASED LIFT REGIME LATE THIS AFTERNOON AND EVENING. DEPENDING ON POOLING OF LLVL DPTS AND AMBIENT HEATING...SBCAPES COULD APPROACH 3000 J/KG. ALTHOUGH VERTICAL SHEAR VALUES APPEAR MARGINAL...FCST SOUNDINGS SUGGEST A TEMPORARY INVERTED-V PROFILE THAT MAY ALLOW FOR SOME STORMS THAT MANAGE TO GROW AND SUSTAIN THEMSELVES FOR A PERIOD...TO POSSIBLY BECOME A WIND BURST POTENTIAL AS WELL AS HAIL PRODUCTION. THIS STRONG OR ISOLATED SVR WINDOW MAY BE LIMITED TO THE AFTERNOON AND EARLY EVENING BEFORE SOUNDINGS BECOME MORE SATURATED BY A LLJ 1.7 TO 1.8+ INCH PWAT FEED. WILL INCREASE POPS AND THE POTENTIAL AS THE DAY PROGRESSES INTO THE LATE AFTERNOON PERIOD. TONIGHT...ONGOING PASSING VORT COMPLEX AND SOUTH TO SOUTHWESTERLY 15 TO 25 KT LLJ FEED WILL CONTINUE TO FESTER SHOWER AND THUNDERSTORM CLUSTERS TONIGHT...WITH THEM STARTING TO DECREASE AND START TO MIGRATE EASTWARD LATE TONIGHT TOWARD DAWN. BUT NOT BEFORE THE LLJ AND ASSOCIATED RATHER DECENT THTA-E FEED PRODUCE A LOCALLY HEAVY RAIN THREAT ESPECIALLY IN AREAS THAT GET HIT BY REPEATED ACTIVITY. THIS COULD BE ALONG THE MAIN LLVL FRONTAL ZONE WHICH RIGHT NOW APPEARS WILL BE GENERALLY BI-SECTING THE CWA FROM NE-TO-WEST/ SOUTHWEST. STORM FLOW VECTORS AND LLJ CONVERGENCE/ORIENTATION ALSO SUGGEST SOME STORM BACK-BUILDING OR TRAINING POTENTIAL TONIGHT UNTIL THEY VEER MORE WESTERLY TOWARD MORNING. WITH THE EXTENT OF PWATS GETTING FED UP INTO THE REGION...COULD EASILY SEE SOME AREAS GETTING FROM 1 INCH OR EVEN UP CLOSE TO 2 INCHES BY TUE MORNING. LOW TEMPS IN THE MID TO UPPER 60S. ..12.. .LONG TERM...(TUESDAY THROUGH NEXT SUNDAY) ISSUED AT 330 AM CDT MON AUG 17 2015 LONG TERM FORECAST HIGHLIGHTS INCLUDE POTENTIAL FOR HEAVY RAIN AND ISOLATED SEVERE STORMS TUESDAY...COOLER TEMPS MID-WEEK...THEN MORE RAIN CHANCES NEXT WEEKEND. THE TUESDAY EVENT MAY DEVELOP IN A COUPLE OF ROUNDS...THE FIRST ASSOCIATED WITH A LEAD VORT MAX AHEAD OF THE MAIN COLD FRONT IN THE AFTERNOON/EVENING...FOLLOWED BY THE MAIN SYNOPTIC COLD FRONT AND FORCING FROM THE UPPER TROUGH LATER TUESDAY NIGHT. THE ENTIRE FORECAST AREA IS NOW INCLUDING IN THE SWODY2 SLIGHT RISK. STRONG WIND GUSTS WILL LIKELY BE THE MAIN THREAT...ALONG WITH POCKETS OF HEAVY RAIN AND PERHAPS ISOLATED FLASH FLOODING GIVEN EXPECTED PWAT VALUES AROUND 2 INCHES. ON WEDNESDAY...EXPECT SOME LINGERING SHOWERS AND MUCH COOLER TEMPERATURES...MAINLY IN THE 70S. THURSDAY'S HIGHS ARE FORECAST IN THE MID TO UPPER 70S...STILL BELOW NORMAL FOR THE DATE. THE NEXT CHANCE OF RAIN WILL BE LATER SATURDAY INTO SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 100 PM CDT MON AUG 17 2015 MVFR/LCL IFR CONDS IN SHOWERS/THUNDERSTORMS THIS AFTERNOON AND TONIGHT ALONG WITH PATCHY FOG. OTHERWISE...MAINLY VFR CONDS. SOUTHWEST WINDS AROUND 10 KNOTS OR LESS THIS AFTERNOON AND VARIABLE AROUND 5 KNOTS TONIGHT THEN SOUTH LESS THAN 10 KNOTS TUESDAY. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && UPDATE...HAASE SYNOPSIS...12 SHORT TERM...12 LONG TERM...RP KINNEY AVIATION...HAASE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 503 AM CDT MON AUG 17 2015 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-181015- 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- 503 AM CDT MON AUG 17 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 THUNDERSTORMS WILL INCREASE ACROSS THE OUTLOOK AREA THIS AFTERNOON AND TONIGHT. IF PORTIONS OF THE OUTLOOK AREA CAN GET ADEQUATE HEATING...A FEW OF THESE STORMS MAY BECOME STRONG TO SEVERE WITH DAMAGING WINDS AND HAIL. THIS ISOLATED SEVERE STORM POTENTIAL WILL END AFTER EARLY EVENING...WITH LOCALLY HEAVY RAIN BECOMING THE MAIN OVERNIGHT THREAT. AREAS THAT GET HIT REPEATEDLY BY STORM ACTIVITY MAY GET OVER AN INCH OF RAIN BY EARLY TUESDAY MORNING. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY EXPECT PERIODS OF THUNDERSTORMS TUESDAY AND TUESDAY NIGHT. A FEW SEVERE STORMS ARE POSSIBLE MAINLY DURING THE AFTERNOON AND EVENING HOURS...WITH DAMAGING WINDS THE MAIN THREAT. POCKETS OF HEAVY RAINFALL ARE ALSO EXPECTED...WITH ISOLATED FLASH FLOODING NOT OUT OF THE QUESTION...ESPECIALLY IN URBAN AREAS. ISOLATED THUNDERSTORMS ARE POSSIBLE WEDNESDAY...BUT ARE NOT EXPECTED TO BE SEVERE. ADDITIONAL THUNDERSTORMS ARE POSSIBLE AGAIN SATURDAY AND SUNDAY WITH ANY SEVERE WEATHER POTENTIAL TO BE DETERMINED. .SPOTTER INFORMATION STATEMENT... THERE IS A LOW CHANCE THAT SPOTTER ACTIVATION WILL BE NEEDED THIS AFTERNOON AND EVENING ACROSS PORTIONS OF THE OUTLOOK AREA. SPOTTER ACTIVATION MAY AGAIN BE NEEDED TUESDAY INTO TUESDAY NIGHT. 12/RP KINNEY
The Quad Cities radar (KDVN), 75 km away, was scanning. The volume nearest the first event began at 18:54 UTC.
3 thunderstorm wind, 1 lightning. Local standard time, as filed.
A trained spotter estimated that thunderstorm winds were gusting to 60 mph. The gusts blew down some 2 inch diameter tree branches. The time of the event was estimated using radar.
A fire department reported that a lightning strike caught a machine shed on fire about 4 miles east southeast of Wapello. The time of the event was estimated using lightning and radar data.
An off duty NWS Employee reported an estimated wind gust to be 60 MPH and blew down a 3 to 4 inch diameter tree branch in neighbor's yard. The time of the event was estimated using radar.
An off duty NWS Employee reported about 4 to 5 inch diameter tree limbs blown down on the southwest side of town with several smaller branches down. The 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 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: 599927, 598595, 598597, 598594.