Scattered showers and thunderstorms developed ahead of a cold front that moved into northwest Illinois during the early evening hours on August 17th. One of these thunderstorms produced 60 mph that caused some 2 inch tree limbs to be knocked down in Rock Island County.
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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.
Scattered showers and thunderstorms developed ahead of a cold front that moved into northwest Illinois during the early evening hours on August 17th. One of these thunderstorms produced 60 mph that caused some 2 inch tree limbs to be knocked down in Rock Island County. 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, 2:13 PM CST, 2 hours 32 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 313 PM CDT MON AUG 17 2015 .SYNOPSIS... ISSUED AT 308 PM CDT MON AUG 17 2015 SCATTERED THUNDERSTORMS WERE OVER THE CWA WITH SOME OF THE STRONGER STORMS PRODUCING OVER 40-50 MPH WINDS AND LOCALLY HEAVY RAINFALL. AT 3 PM TEMPERATURES RANGED FROM THE UPPER 70S NW TO THE UPPER 80S FAR EAST. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 308 PM CDT MON AUG 17 2015 FORECAST FOCUS ON THUNDERSTORMS. TONIGHT...A COLD FRONT IN OUR NW CWA WILL SLIDE SOUTHEAST BUT THEN EVENTUALLY RETURN NORTHWARD AS A WARM FRONT TOWARDS MORNING. A DECENT SHORT WAVE SEEN ON WATER VAPOR LOOPS IN ALONG THE IA/NEB BORDER WILL MOVE ACROSS IA AND INTO NORTHERN IL. STRONG FORCING FROM THIS WAVE WILL INCREASE SHOWERS AND THUNDERSTORMS THIS EVENING. I WILL CONTINUE WITH LIKELY POPS THIS EVENING. PWAT'S INCREASE TO OVER 2 INCHES WHICH WILL FAVOR LOCALLY HEAVY RAINFALL IN THE STRONGER STORMS. HOWEVER...SHEAR IS WEAK AND WITH THE FORECAST SOUNDING SHOWING A VERY MOIST COLUMN THE THREAT FOR SEVERE WEATHER IS VERY LOW. AFTER MIDNIGHT...BEHIND THE PASSAGE OF THE WAVE THE FORCING DIMINISHES SO I WILL HAVE DECREASING POPS. MINIMUM TEMPERATURES WILL BE IN THE MID TO UPPER 60S. TUESDAY...A POTENT SHORT WAVE CURRENTLY IN THE NORTHERN ROCKIES WILL DEEPEN INTO AN UNSEASONABLY STRONG UPPER LEVEL LOW THAT WILL SWING INTO THE PLAINS AND UPPER MIDWEST. A DEEPENING CYCLONE WILL TRACK FROM NEB INTO SOUTHERN MN BY EVENING. THIS WILL SEND A STRONG COLD FRONT INTO WESTERN IA BY LATE AFTERNOON. LARGE SCALE ASCENT IN ASSOCIATION WITH THE TROUGH WILL SPREAD OVER THE REGION. SCATTERED THUNDERSTORMS MAY LINGER IN THE MORNING BUT THE MORE WIDESPREAD SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THE AFTERNOON. DEEP LAYER SHEAR WILL GRADUALLY INCREASE LATER IN THE DAY BUT THE MAIN SEVERE WEATHER THREAT SHOULD REMAIN WEST OF THE CWA CLOSER TO THE COLD FRONT. HOWEVER...CAN'T RULE OUT ISOLATED SEVERE STORMS IN THE AFTERNOON ESPECIALLY IN OUR WESTERN COUNTIES. AT THIS TIME THIS LOOKS TO BE A HIGH SHEAR/LOW CAPE EVENT WHICH WOULD FAVOR DAMAGING WINDS. CONSIDERABLE CLOUDINESS WILL KEEP AFTERNOON TEMPERATURES IN THE UPPER 70S TO LOWER 80S. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 308 PM CDT MON AUG 17 2015 TURNING SIGNIFICANTLY COOLER FOR MID WEEK. TEMPERATURES TO REMAIN AT OR A LITTLE BELOW NORMAL THROUGH NEXT WEEKEND. THE MAIN LOW FROM THE STORM SYSTEM MOVES THROUGH THE MIDWEST TUESDAY NIGHT. THE STRONGEST FORCING COMES THROUGH TUESDAY EVENING FOLLOWED BY THE COLD FRONT LATE TUESDAY NIGHT. STORMS SHOULD BE MOVING AT A FAIRLY GOOD PACE BUT THE OVERALL FORCING AND MOISTURE AVAILABILITY SUGGESTS THE POSSIBILITY OF SOME LOCALLY HEAVY RAINFALL. BREEZY AND MUCH COOLER CONDITIONS WILL BE SEEN ACROSS THE AREA ON WEDNESDAY. WRAP AROUND CLOUDS FROM THE DEPARTING STORM SYSTEM WILL BE ACROSS THE AREA WITH ISOLATED TO SCATTERED SHOWERS. THE COMBINATION OF BRISK WINDS...CLOUD COVER...AND PRECIPITATION MAY KEEP THE NORTHWEST QUARTER OF THE AREA IN THE 60S WITH THE REMAINDER OF THE AREA BARELY GETTING INTO THE LOWER 70S. LINGERING SPRINKLES ARE POSSIBLE ACROSS THE NORTH THIRD OF THE AREA WEDNESDAY EVENING. LATE WEDNESDAY EVENING AND OVERNIGHT WILL SEE DRY CONDITIONS WITH CLEARING SKIES. LOW TEMPERATURES SHOULD BE ACHIEVED AROUND OR JUST AFTER SUNRISE WITH LOWS IN THE 50S. THE WAPSI VALLEY AND OTHER FAVORED COOL AREAS MAY SEE SPOTTY UPPER 40S FOR LOWS. DRY AND COOL CONDITIONS WILL BE SEEN ACROSS THE AREA ON THURSDAY AS HIGH PRESSURE STARTS BUILDING INTO THE MIDWEST. THURSDAY NIGHT ON... QUIET AND COOL CONDITIONS WILL BE SEEN THURSDAY NIGHT AND FRIDAY AS THE CANADIAN HIGH MOVES THROUGH THE AREA. TEMPERATURES WILL AVERAGE BELOW NORMAL. RETURN FLOW DEVELOPS ACROSS THE AREA FRIDAY NIGHT. THE MODEL CONSENSUS HAS MOST OF THE AREA DRY BUT DOES HAVE SOME SLIGHT CHANCE POPS OVER THE SOUTHWEST HALF OF THE AREA. TEMPERATURES SHOULD BE CLOSE TO NORMAL. SATURDAY AND SUNDAY THE MODEL CONSENSUS HAS CHANCE POPS ACROSS THE AREA AS THE NEXT STORM SYSTEM MOVES THROUGH THE MIDWEST. THERE ARE SOME DIFFERENCES IN TIMING AMONG THE MODELS SO A PART OF SATURDAY MIGHT BE DRY. TEMPERATURES SHOULD AVERAGE CLOSE TO NORMAL. THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS SUNDAY NIGHT FOR LINGERING PRECIPITATION BEHIND THE DEPARTING STORM SYSTEM. LOW TEMPERATURES WILL BE COOLER THAN NORMAL. THE MODEL CONSENSUS HAS DRY CONDITIONS FOR THE AREA ON MONDAY AS ANOTHER COOL CANADIAN HIGH PRESSURE BUILDS INTO THE MIDWEST. TEMPERATURES WILL AVERAGE BELOW NORMAL. && .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. && SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...08 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
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE QUAD CITIES IA IL 226 PM CDT MON AUG 17 2015 IAZ067-068-ILZ015-172130- MUSCATINE-SCOTT-ROCK ISLAND- INCLUDING THE CITIES OF...MUSCATINE...BETTENDORF...DAVENPORT... MOLINE...ROCK ISLAND 226 PM CDT MON AUG 17 2015 ...STRONG THUNDERSTORM APPROACHING THE QUAD CITIES... AT 225 PM A STRONG THUNDERSTORM WAS LOCATED NEAR PLEASANT PRAIRIE IN EXTREME EASTERN MUSCATINE COUNTY. THIS STORM WAS MOVING NORTHEAST AT 20 MPH AND WAS PRODUCING WIND GUSTS OVER 40 MPH AND HEAVY RAINFALL. OCCASIONAL CLOUD TO GROUND LIGHTNING WAS ALSO OCCURRING WITH THIS STORM. THE STORM WILL IMPACT THE QUAD CITIES AREA INCLUDING BLUE GRASS... WEST LAKE PARK...DAVENPORT AND BETTENDORF THROUGH 330 PM. YOU SHOULD SEEK SHELTER IN A STURDY BUILDING WHEN THIS STORM APPROACHES. HAASE
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE QUAD CITIES IA IL 328 PM CDT MON AUG 17 2015 IAZ064-065-077-172230- JOHNSON-CEDAR-WASHINGTON- INCLUDING THE CITIES OF...IOWA CITY...TIPTON...WASHINGTON 328 PM CDT MON AUG 17 2015 ...A STRONG THUNDERSTORM APPROACHING IOWA CITY... AT 325 PM A STRONG THUNDERSTORM WAS LOCATED NEAR KALONA AND WELLMAN IN NORTHERN WASHINGTON COUNTY. THIS STORM WAS MOVING NORTHEAST AT 20 MPH AND WAS PRODUCING WIND GUSTS OVER 40 MPH AND HEAVY RAINFALL. OCCASIONAL CLOUD TO GROUND LIGHTNING WAS ALSO OCCURRING WITH THIS STORM. THE STORM WILL IMPACT THE IOWA CITY AREA INCLUDING HILLS THROUGH 430 PM. YOU SHOULD SEEK SHELTER IN A STURDY BUILDING WHEN THIS STORM APPROACHES. HAASE
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
458 PM CDT MON AUG 17 2015
IAC087-095-101-103-107-115-177-183-172300-
LOUISA-IOWA-WASHINGTON-JEFFERSON-JOHNSON-VAN BUREN-HENRY-KEOKUK-
458 PM CDT MON AUG 17 2015
...AN AREA OF THUNDERSTORMS...SOME STRONG POSSIBLE THROUGH 6 PM...
AT 456 PM CDT...AN AREA OF THUNDERSTORMS...SOME STRONG WAS OVER
BRIGHTON...OR 8 MILES SOUTHWEST OF WASHINGTON...MOVING NORTHEAST AT
55 MPH.
WINDS IN EXCESS OF 40 MPH ARE POSSIBLE WITH THIS STORM.
LOCATIONS IMPACTED INCLUDE...
IOWA CITY...FAIRFIELD...WASHINGTON...SIGOURNEY...KEOSAUQUA...
KALONA...WELLMAN...WINFIELD...NORTH ENGLISH...RIVERSIDE...WAYLAND...
HEDRICK...HILLS...BRIGHTON...WHAT CHEER...RICHLAND...AINSWORTH...
BATAVIA...BIRMINGHAM AND DELTA.
TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY CAUSE
LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.
LAT...LON 4151 9238 4151 9230 4165 9230 4164 9151
4113 9136 4065 9209 4080 9218 4116 9218
4116 9239 4119 9241
TIME...MOT...LOC 2156Z 240DEG 49KT 4119 9179
NICHOLSThe Quad Cities radar (KDVN), 13 km away, was scanning. The volume nearest the first event began at 22:46 UTC.
1 thunderstorm wind. Local standard time, as filed.
A trained spotter reported an estimated wind gust of 60 MPH. The gust blew down some 2 inch diameter branches on the west side of Moline. The time of the event was estimated using radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2015Every state in 2015This day in weather historyWarnings in Illinois, 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: 598599.