An upper level disturbance moved over eastern Iowa and northwest Illinois August 1, sparking some scattered showers and thunderstorms. One storm in Rock Island, IL surpassed severe thresholds producing hailstones the size of a quarter.
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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.
An upper level disturbance moved over eastern Iowa and northwest Illinois August 1, sparking some scattered showers and thunderstorms. One storm in Rock Island, IL surpassed severe thresholds producing hailstones the size of a quarter.
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 1, 2:09 PM CST, 3 hours 27 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 309 PM CDT FRI AUG 1 2014 .SYNOPSIS... ISSUED AT 240 PM CDT FRI AUG 1 2014 12Z UA ANALYSIS HAS SEVERAL WEAK TROFS FROM THE OHIO VALLEY BACK INTO THE UPPER MIDWEST. A SLIGHTLY HIGHER POOL OF MOISTURE WAS NOTED AT 850MB ACROSS IOWA AND SOUTHERN MINNESOTA. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON SHOW CONVECTION ACROSS THE AREA WITH THE MORE WIDESPREAD CONVECTION FROM CENTRAL INTO EASTERN ILLINOIS. 18Z SFC ANALYSIS HAS HIGH PRESSURE OVER THE AREA WITH VERY SUBTLE TROFS FROM NORTHEAST ILLINOIS BACK INTO MINNESOTA. DEW POINTS WERE IN THE 60S FROM THE LOWER MISSISSIPPI VALLEY TO JUST SOUTH OF THE GREAT LAKES WITH 50S ACROSS THE WESTERN PLAINS AND UPPER MIDWEST. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 240 PM CDT FRI AUG 1 2014 SATELLITE TRENDS WOULD SUPPORT ISOLATED TO LOW END SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE PEAK HEATING OF LATE AFTERNOON. BY EARLY EVENING AND THROUGH SUNSET THE OVERALL FORCING WEAKENS AGAIN SO CONVECTION WILL BECOME MORE ISOLATED IN NATURE WITH ANY LINGERING SHOWERS AND STORMS ENDING SHORTLY AFTER SUNSET. FROM LATE EVENING THROUGH SUNRISE SATURDAY DRY CONDITIONS ARE EXPECTED. THE LIGHT WINDS OVERNIGHT MAY ALLOW SOME PATCHY FOG TO DEVELOP WITH RIVER VALLEYS AND LOW LYING AREAS BEING THE MOST FAVORED. SATURDAY WILL START OUT DRY ACROSS THE AREA WITH DIURNAL CLOUDS DEVELOPING BY LATE MORNING AND CONTINUING THROUGH THE AFTERNOON. ANOTHER WEAK DISTURBANCE ALOFT WILL MOVE THROUGH THE AREA WHICH SHOULD INITIATE DIURNAL CONVECTION STARTING AROUND MID DAY AND CONTINUING THROUGH SUNSET. DUE TO THE WEAK FORCING...ANY SHOWERS OR STORMS WOULD BE ISOLATED TO LOW END SCATTERED IN NATURE AND WOULD BE MOST NUMEROUS FROM MID AFTERNOON THROUGH SUNSET. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 240 PM CDT FRI AUG 1 2014 CONTINUED GENERALLY BELOW NORMAL TEMPERATURES AND LIKELY HOOD OF SIGNIFICANT RAINS MIDDLE OF NEXT WEEK. OVERVIEW...INITIALIZATION AND VERIFICATION GOOD WITH NORMAL MINOR UPPER LEVEL KINEMATIC VARIANCES AND MOST SOLUTIONS SLIGHTLY TOO MOIST IN BL RESULTING IS SLIGHTLY TOO HIGH GUIDANCE POPS INTO MIDDLE OF NEXT WEEK. PERSISTENCE SUPPORT HIGHS AND LOWS A FEW DEGREES NEAR GUIDANCE BLEND THROUGH MONDAY. RUN TO RUN VARIANCES SUPPORTS A 70/30 MIX OF HI-RES ECMWF/GEM-NH TO GFS AS GFS TOO FAR SOUTH WITH SYSTEM NEXT WEEK. NORTHWEST FLOW TO ALMOST GUARANTEE HIGHS TO STAY BELOW 90 DEGREES NEXT 7 DAYS AS OUR COOL SUMMER CONTINUES WITH UNSEASONABLY COOL HIGHS POSSIBLE WED/THU. SATURDAY NIGHT THROUGH MONDAY...CONTINUED NORTHWEST FLOW WITH WEAK UPPER DISTURBANCES AHEAD OF NEXT WAVE NEXT WEEK. TEMPERATURES SLIGHTLY BELOW NORMAL THROUGH SUNDAY WITH THEN NEAR NORMAL TEMPERATURES SUNDAY AND MONDAY. LOW POPS...MOSTLY LATE PM...TO GRADUALLY INCREASE SUNDAY AND MONDAY WITH SLIGHTLY INCREASED FORCING AND DEWPOINTS INTO LOWER 60S. LIMITED INSTABILITY AOB 1500 J/KG AND FREEZING LEVELS AOA 11K AGL SUGGEST LITTLE OR NO RISK OF SEVERE STORMS WITH LOCALLY LIGHT TO MODERATE RAINFALL TOTALS. PATCHY LATE SUMMER MORNING FOG MAY BE POSSIBLE WITH LIGHT WINDS AND HAZY SKIES OVER SEVERAL DAY PERIOD SUGGESTS ISOLATED AIR QUALITY ISSUES CONDITIONS MAY BE POSSIBLE. TUESDAY THROUGH THURSDAY...NORTHWEST FLOW WAVE TO RESULT IN BACKDOOR COOL FRONT AND FLOW OFF LAKE MICHIGAN AND SURFACE WAVE TO BRING WIDESPREAD RAINS WITH 1 TO OVER 2 INCHES POSSIBLE WITH RAIN AND EMBEDDED THUNDER SUGGESTED DUE TO STRONG EVAPORATIVE COOLING. NEAR RECORD TO RECORD COOL LAKE MICHIGAN WATER TEMPERATURES SUPPORTS RISK OF HIGHS WED/THU TOO HIGH BY 5 TO 8+ DEGREES WITH NEAR RECORD COOL HIGHS ONCE AGAIN POSSIBLE IF TRENDS CONTINUE FOR LATER SHIFTS...THIS MEANS HIGHS IN THE UPPER 60S TO LOWER 70S NOT OUT OF THE QUESTION AND THIS RISK WILL BE BETTER CLARIFIED IN THE NEXT 24 TO 36 HOURS. LOW RISK OF SEVERE STORMS CONTINUE AS AREA SHOULD BE ON THE COOL SIDE OF FRONTAL BOUNDARY. LOWS IN THE UPPER 50S TO LOWER 60S ARE SUGGESTED. FRIDAY...NEARBY FRONTAL BOUNDARY SUPPORTS CONTINUED CHANCE POPS WITH LOW CONFIDENCE ON POPS AND TEMPERATURES. TRENDS SUGGEST COOL EASTERLY WINDS WITH SOME RISK OF MORE SHOWERS AND POSSIBLE STORMS FROM OVERRUNNING. HIGH TEMPERATURES ONCE AGAIN MAY BE A BIT TOO HIGH IF EAST WINDS DO OCCUR OFF LAKE MICHIGAN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 240 PM CDT FRI AUG 1 2014 VFR CONDITIONS ARE EXPECTED THROUGH 06Z/02 AS HIGH PRESSURE REMAINS ACROSS THE AREA. DIURNAL CONVECTION OF SHRA/TSRA ARE EXPECTED THROUGH SUNSET. DUE TO NEW CONVECTION DEVELOPING ACROSS EASTERN IOWA...ALL 18Z TAFS WERE AMENDED TO INCLUDED VCTS. THE PROBABILITY OF A SHRA/TSRA HITTING A TAF SITE IS AROUND 10 PERCENT. AFT 06Z/02 MVFR CONDITIONS ARE EXPECTED TO DEVELOP DUE TO LIGHT WINDS. THE POTENTIAL DOES EXIST FOR SPOTTY IFR/LIFR CONDITIONS IN GROUND FOG. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && SYNOPSIS...08 SHORT TERM...08 LONG TERM...NICHOLS AVIATION...08
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 414 AM CDT FRI AUG 1 2014 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-020915- 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- 414 AM CDT FRI AUG 1 2014 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 ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE TODAY AND THIS EVENING. ALTHOUGH WIDESPREAD SEVERE WEATHER IS NOT EXPECTED...A FEW OF THE STRONGER STORMS MAY BE ABLE TO PRODUCE HAIL UP TO THE SIZE OF PENNIES. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THERE IS A CHANCE OF THUNDERSTORMS MAINLY MONDAY THROUGH THURSDAY WITH THE BEST CHANCES LATE WEDNESDAY INTO THURSDAY. LIGHTNING WILL BE THE MAIN THREAT WITH THESE THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY AND TONIGHT. 12/WOLF
The Quad Cities radar (KDVN), 12 km away, was scanning. The volume nearest the first event began at 23:37 UTC.
1 hail. Local standard time, as filed.
Quarter sized hail fell for about 2 to 3 minutes in Rock Island, IL around 636 pm CDT August 1. The hailstorm lasted on and off for about 45 minutes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2014Every state in 2014This day in weather historyWarnings in Illinois, August 2014
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: 524785.