Scattered thunderstorms developed across north central Iowa along an elevated convergence zone in a near tropical atmosphere. Feed by a low level jet of 30 knots (about 35 mph), the thunderstorms evolved into a squall line that raced east southeast across eastern Iowa and northern Illinois.
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.
Scattered thunderstorms developed across north central Iowa along an elevated convergence zone in a near tropical atmosphere. Feed by a low level jet of 30 knots (about 35 mph), the thunderstorms evolved into a squall line that raced east southeast across eastern Iowa and northern Illinois. Wind damage was the most common severe report with severe crop damage occurring across a large portion of Benton County, and to a lesser extent across Iowa, Linn, and Clinton Counties. The wind combined with a large amount of cloud to ground lightning resulted in power failures across parts of eastern Iowa and took two public safety communication towers off the air.
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 10, 2:32 AM CST, 3 hours 26 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 332 AM CDT THU AUG 10 2006 .DISCUSSION... MAIN FEATURE OF NOTE THIS MORNING IS STRONG MCS OVER NEB. RADAR AND SATELLITE TRENDS INDICATE MCS IS MAKING A RIGHT TURN AND MOVING MORE ENE OR E...AND LAST COUPLE OF SCANS INDICATE WEAKENING TREND. PERSISTENT AREA OF STRENGTHENING TSRA HAS MOVED ACROSS NRN IA THIS MORNING AS WELL...AND SMALLER CELLS WERE DEVELOPING ROUGHLY ALONG A LINE FROM DEWITT IA TO PRINCETON IL. RADAR TRENDS INDICATE THOSE AREAS OF CONVECTION MAY BE TRYING TO LINK INTO A BAND. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES WEAK WARM FRONT FEATURE EXTENDING ACROSS THE DAKOTAS/MN THROUGH WI. 850MB MOISTURE HAD POOLED OVER SRN MN/NRN IA. 500MB ANALYSIS INDICATED SERIES OF WEAK SHORTWAVES...INCLUDING ONE OVER IA/NWRN MO/KS...ONE IN THE CTRL DAKOTAS...AND TROUGH AXIS ACROSS MT/ID/UT...AS WELL AS AN UPPER RIDGE ACROSS MB/SASK/MT. UPPER-LEVEL JET RIGHT ENTRANCE REGION WAS DIRECTED TOWARD ERN NEB/WRN IA...WITH JET CURVING ACROSS MN/WI/MI/OH/PA. 07Z MSAS ANALYSIS INDICATES SURFACE LOW EXTENDS FROM ERN NEB SWWD TOWARD NWRN KS. SFC WARM FRONT WAS EVIDENT FROM ERN NEB TO NEAR KCNC TO KGBG TO KVYS...WITH VERY MOIST POOL OF DEWPOINTS IN THE MID 70S ACROSS IA/IL. PROFOUND LACK OF MODEL ABILITY TO DEPICT ONGOING CONVECTION THIS MORNING... AS STRONG MCS OVER NEB/WRN IA DOES NOT SHOW UP IN ANY OF THE MODELS. THIS OBVIOUSLY CREATES A LACK OF CONFIDENCE IN MODEL RESOLUTION OF THE NEXT 12-24 HR AND REALLY IN ALL OF THE RUNS. AS A RESULT...FORECAST IS LOW CONFIDENCE AND BASED MAINLY ON PATTERN RECOGNITION AND PERSISTENCE AS WELL AS BLEND OF MODEL SOLUTIONS. ELEVATED TSRA CURRENTLY DEVELOPING SHOULD PERSIST THROUGH MORNING...AND EXPECT MCS TO PERSIST THROUGH MORNING AS WELL...ENTERING THE CWA BY MID-MORNING. HAVE POPS IN THE LIKELY CATEGORY FOR MUCH OF THE CWA THIS MORNING...TAPERING TO CHANCES AS ACTIVITY FIZZLES AND MOVES EASTWARD DURING THE LATE MORNING/AFTERNOON. FAVORED LOCATION FOR CONVECTIVE DEVELOPMENT THIS AFTERNOON/EVENING DEPENDS STRONGLY ON LOCATION OF WARM FRONT...WHICH WILL HAVE A HARD TIME PROGRESSING NORTH INTO CLOUD DEBRIS. EXPECT IT TO LINGER ALONG THE IA/MO BORDER OR ACTUALLY SAG SOUTHWARD BACK INTO MO. LOWER CAPES N OF THE BOUNDARY WOULD LIMIT SEVERE POTENTIAL...WHILE AREAS ALONG AND SOUTH OF THE BOUNDARY SHOULD DEVELOP TSRA IN THE AFTERNOON AND EVENING. HAVE JUST CHANCE POPS SOUTH WITH THEORY THAT FRONT WILL BE SOUTH OF THE CWA. TEMPS TODAY ARE AGAIN TRICKY WITH POTENTIAL FOR CLOUDS TO MUDDY THE FORECAST...AND HAVE GONE TO LOW END OF GUIDANCE FOR TODAY. HAVE INCLUDED SLIGHT CHANCE OF PRECIP ON FRI AS SEVERAL RUNS OF THE NAM AND ECMWF HAVE INDICATED PRECIP AS A WAVE PASSES THROUGH THE GREAT LAKES AND RIGHT ENTRANCE REGION OF JET MOVES ACROSS CWA. WITH SO MUCH MOISTURE IN THE AIR...HARD TO LEAVE FORECAST DRY GIVEN THAT MUCH SUPPORT FOR PRECIP. DID KEEP SAT INTO SUN DRY AS HIGH SHOULD BE BETTTER ENTRENCHED IN THE CWA WITH DRY AIR ADVECTION SAT. RETURN FLOW KICKS IN AGAIN SUN AS HIGH PULLS EASTWARD...BUT NEXT FRONT IS STILL WELL UPSTREAM ON SUN. OVERALL...KEPT TEMPS CLOSE TO GUIDANCE AND KEPT PERSISTENCE OF FORECAST FROM LAST SEVERAL MORNINGS. MADE NO CHANGES TO DAYS 4-7. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && MAYES
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 505 AM CDT THU AUG 10 2006 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-111015- 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- 505 AM CDT THU AUG 10 2006 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 A LINE OF STRONG TO SEVERE THUNDERSTORMS WILL AFFECT EASTERN IOWA AND NORTHWESTERN ILLINOIS THIS MORNING. SOME OF THESE THUNDERSTORMS MAY CONTAIN DAMAGING WINDS AND HAIL UP TO THE SIZE OF NICKELS. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE AS SLOW-MOVING THUNDERSTORMS LINGER ACROSS SMALL AREAS FOR LONG PERIODS OF TIME. THE HEAVY RAINS MAY PRODUCE PONDING IN ROADWAYS AND LOW-LYING AREAS...AS WELL AS RAPID RISES IN SMALL STREAMS. AREAS NORTH OF INTERSTATE 80 ARE MOST AT RISK THIS MORNING. LATER TODAY...STORMS ARE EXPECTED TO DEVELOP ALONG A WARM FRONT. THE EVENTUAL LOCATION OF THE FRONT IS UNCERTAIN AS STORMS MOVING FROM THE WEST WILL AFFECT ITS POSITION...BUT IS EXPECTED TO BE NEAR THE IOWA/MISSOURI BORDER EXTENDING INTO WEST CENTRAL ILLINOIS. WHERE THESE STORMS DO DEVELOP...THEY WILL BRING A THREAT OF SEVERE WEATHER...WITH DAMAGING WINDS...MARGINALLY SEVERE HAIL...AND LOCALLY HEAVY RAINS THE PRIMARY THREATS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THERE IS A SLIGHT CHANCE OF THUNDERSTORMS ON FRIDAY...BUT SEVERE WEATHER IS NOT ANTICIPATED. THERE IS A CHANCE OF THUNDERSTORMS AGAIN ON SUNDAY NIGHT INTO MONDAY. THE POTENTIAL FOR SEVERE WEATHER WITH THESE STORMS IS STILL UNCERTAIN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS MORNING NORTH OF A LINE FROM FAIRFIELD IOWA TO GALESBURG ILLINOIS...AND SPOTTER ACTIVATION IS POSSIBLE LATER THIS AFTERNOON INTO THIS EVENING SOUTH OF THAT LINE.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
517 AM CDT THU AUG 10 2006
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0516 AM TSTM WND GST 1 E MARION 42.03N 91.57W
08/10/2006 E60 MPH LINN IA TRAINED SPOTTER
CORNER OF HWY 151 AND HWY 13. WINDS ESTIMATED 55-60 MPH.
&&
MAYESPRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
518 AM CDT THU AUG 10 2006
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0515 AM TSTM WND GST MARION 42.03N 91.59W
08/10/2006 E70.00 MPH LINN IA TRAINED SPOTTER
WIND GUSTS ESTIMATED 60-70 MPH.
&&
MAYESPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
526 AM CDT THU AUG 10 2006
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0520 AM HAIL 1 N MARION 42.05N 91.59W
08/10/2006 E0.88 INCH LINN IA BROADCAST MEDIA
PENNY TO NICKEL SIZE HAIL ON COUNTY HOME RD 1.5 MI W OF
HWY 13. ALSO TORRENTIAL RAIN AND WINDS GUSTING TO 45 MPH.
&&
MAYESPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
549 AM CDT THU AUG 10 2006
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0545 AM HEAVY RAIN CEDAR RAPIDS 41.97N 91.67W
08/10/2006 M1.20 INCH LINN IA TRAINED SPOTTER
SPOTTER REPORTED 1.20 INCHES OF RAINFALL IN PAST 30
MINUTES. SPOTTER ALSO ESTIMATED WINDS GUSTS OF 45 TO 50
MPH AS THE RAIN BEGAN AT ABOUT 0515 A.M.
&&
MIKEZPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
648 AM CDT THU AUG 10 2006
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0642 AM TSTM WND GST DEWITT 41.82N 90.55W
08/10/2006 E60 MPH CLINTON IA NWS EMPLOYEE
NWS EMPLOYEE REPORTED 50 TO 60 MPH WIND GUSTS.
&&
MIKEZPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
657 AM CDT THU AUG 10 2006
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0645 AM TSTM WND DMG 4 W MAQUOKETA 42.07N 90.74W
08/10/2006 JACKSON IA CO-OP OBSERVER
6 IN TREE LIMBS DOWN AND POWER OUT. ALSO 1.13 IN OF RAIN.
&&
MAYESThe Quad Cities radar (KDVN), 40 km away, was scanning. The volume nearest the first event began at 11:58 UTC.
5 thunderstorm wind. Local standard time, as filed.
The highway department reported branches and limbs down on Kennedy Road.
A storm survey discovered 6 to 12 inch diameter limbs down on a farm.
A storm survey discovered 6 to 8 inch diameter limbs down on the west side of highway 40.
A storm survey discovered numerous 3 to 5 inch diameter limbs down on the northwest side of the city.
A storm survey discovered numerous 2 to 12 inch diameter limbs down along highway 40 to the Sterling city limits.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2006Every state in 2006This day in weather historyWarnings in Illinois, August 2006
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: 5528348, 5528419, 5528420, 5528421, 5528422.