An outflow boundary from convection in Minnesota combined with an upper level disturbance, a weak low level jet, a semi-moist atmosphere, and a warm front running from central Iowa to central Illinois to produce a severe mesoscale convective system across eastern Iowa and northern Illinois. Numerous measuring equipment at airports and spotters reported winds of 43 to 49 knots (50 to 56 mph)…
Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
An outflow boundary from convection in Minnesota combined with an upper level disturbance, a weak low level jet, a semi-moist atmosphere, and a warm front running from central Iowa to central Illinois to produce a severe mesoscale convective system across eastern Iowa and northern Illinois. Numerous measuring equipment at airports and spotters reported winds of 43 to 49 knots (50 to 56 mph) associated with the gust front. Numerous trees were downed and sections of corn fields were laid flat by gusts associated with the storms that exceeded 52 knots (60 mph). Due to high freezing levels in the atmosphere, very little hail was reported.
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 Jul 19, 6:12 AM CST, 3 hours 58 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE QUAD CITIES IA IL 712 AM CDT WED JUL 19 2006 .UPDATE... SHOWERS AND THUNDERSTORMS HAVE BEGUN TO DEVELOP IN NORTHWEST AND NORTH CENTRAL IOWA AS THE LLJ TILT TOWARD THE AREA. THIS TREND IS SHOWN BY PREVIOUS MODELS TO CERTAIN DEGREES WITH OR WITHOUT SATURATION. SINCE IT LOOKS TO FOLLOW THE WET SOLUTION...WE HAVE BUMPED UP POPS FOR SCATTERED STORMS IN IOWA. ALSO...THE MCS OVER THE DAKOTAS AND WESTERN MN HAS NOW BEGUN TO SHIFT SOUTHEAST. THIS IS NOT HANDLED BY ANY MODEL...AND SHOULD IT NOT DIE SOON...A MAJOR UPDATE TO LOWER TEMPERATURES MAY BE NEEDED. ...ERVIN... && .PREVIOUS DISCUSSION... LATEST SFC AND MSAS ANALYSIS WAS INDICATING RING OF 70+ SFC DPTS TO THE SOUTH AND WEST OF THE FCST AREA AND GRT LKS RIDGE. AS THIS RIDGE RETREATS EAST AND SFC LOW ASSOCIATED WITH NEXT MAIN UPPER WAVE IN MEAN WESTERLIES PROPAGATES EAST...THESE HIGH SFC MOISTURE FIELDS WILL SLOSH BACK ACRS THE CWA FROM THE SOUTH AS SSE BOUNDARY LAYER FLOW ORGANIZES. IF FULL INSOLATION WOULD ACCOMPANY THE INCREASE IN HUMIDITY AND AMBIENT TEMPS WOULD REACH THE WARMER THERMAL GUIDANCE FOR TODAY...THE SOUTHERN HALF OF THE CWA WOULD RETURN TO HEAT ADVISORY CRITERIA THIS AFTERNOON. BUT WILL GO WITH THE LOWER TEMP GUIDANCE BANKING ON SOME RETURN FLOW AC AND POSSIBLE DEBRIS FROM CONVECTIVE SYSTEMS UPSTREAM. A FEW ELEVATED/HIGH BASED SHOWERS MAY EVEN DEVELOP ACRS CENTRAL INTO EASTERN IA BY MIDDAY AND INTO THE EARLY AFTERNOON. STILL...THE SOUTHERN CWA COULD REACH THE MID 90S WITH LOW TO MID 70 DPTS AND TICKLE THE 105 HEAT ADVISORY CRITERIA MARK FOR A FEW HOURS BUT NOT LONG ENOUGH TO WARRANT AN ADVISORY. MAIN FCST CONCERN THIS GO AROUND IS THE POTENTIAL FOR A SEVERE MCS TO PROPAGATE INTO THE CWA TONIGHT. IN A NUTSHELL...ENHANCED/ INCREASING LLJ AHEAD OF INCOMING WAVE WILL LOOK TO IMPINGE ON TIGHTENING BOUNDARY AND OUTFLOW REMNANTS FROM ONGOING ELEVATED MCS NOW PUSHING ACRS THE EASTERN DAKOTAS AND INTO WEST CENTRAL MN. ACCEPTED CONVECTIVE SPAWNING GROUNDS ALL POINTING ACRS NORTH CENTRAL IA AND SOUTHERN MN BORDER REGION...WITH PROGGED LLVL THTA-E ADVECTION AND CONVERGENCE OFF THE CHARTS IN THAT REGION. WESTERLY FLOW IN THE H8-H7 MB LAYER WILL PUMP UP WARM WEDGE/CAP ACRS MUCH OF IA...KEEPING DEEP CONVECTION LOCALLY AT BAY ACRS MUCH OF THE STATE FOR MOST OF THE DAY...AGAIN UNTIL STORMS FIRE ON NORTHERN FRINGE OF BUILDING WARM DOME IN VCNTY OF APPROACHING UPPER WAVE AND SOUTHERN EDGE OF UPPER JET EFFECT. INITIAL CONVECTION SHOULD BE SUPERCELLULAR IN NATURE ALONG MN/IA BORDER...AND EVOLVE INTO A SEVERE MCS WITH MAIN STEERING THICKNESSES PROBABLY SHUTTLING SOME OF THIS ACTIVITY INTO AT LEAST THE NORTHERN THIRD OF THE CWA LATER THIRD EVENING AS IT CONTINUES TO FEED ON SUBSTANTIAL LLVL JET/THTA-E FEED. DAMAGING WIND AND HAIL THE MAIN THREATS INTO THE NORTHERN CWA...AND TORNADIC THREAT NOT OUT OF THE QUESTION IF MAIN WARM FRONT LINGERS ACRS PORTIONS THIS AREA AND A CELL MAINTAINS AND ENFLAMES ALONG THIS FEATURE. STOUTNESS OF CAP SHOULD ERODE CONVECTION AS IT TRIES TO PUSH SOUTH OF THE I80 CORRIDOR...WITH LINGERING SVR THREAT TRANSLATING TO HAIL WITH ELEVATED SOUTHWARD PUSHING STORMS. THE FAR SOUTHERN CWA MAY ONLY EXPERIENCE DECAYING ELEVATED DEBRIS-SHOWERS BY LATE TONIGHT-EARLY THU MORNING. WITH THE MAIN SFC BOUNDARY LINGERING ACRS THE SOUTHERN CWA ON THU... WILL KEEP LOW CHC POPS ACRS THE SOUTHERN 2/3S OF THE CWA. TEMPS TRICKY WITH BOUNDARY/IES AND DEBRIS HAVING TO BE TAKEN INTO ACCOUNT ...AND MAY GO WITH HAPPY MEDIUM OF MID TO UPPER 80S IN MOST OF THE LOCAL FCST AREA.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && 12
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE QUAD CITIES IA IL 745 AM CDT WED JUL 19 2006 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-201000- BENTON IA-BUCHANAN IA-BUREAU IL-CARROLL IL-CEDAR IA-CLARK MO- CLINTON IA-DELAWARE IA-DES MOINES IA-DUBUQUE IA-HANCOCK IL- HENDERSON IL-HENRY IA-HENRY IL-IOWA IA-JACKSON IA-JEFFERSON IA- JO DAVIESS IL-JOHNSON IA-JONES IA-KEOKUK IA-LEE IA-LINN IA-LOUISA IA- MCDONOUGH IL-MERCER IL-MUSCATINE IA-PUTNAM IL-ROCK ISLAND IL- SCOTLAND MO-SCOTT IA-STEPHENSON IL-VAN BUREN IA-WARREN IL- WASHINGTON IA-WHITESIDE IL- 745 AM CDT WED JUL 19 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 THERE IS A MODERATE RISK FOR SEVERE STORMS OVER NORTHEAST IOWA TODAY AND TONIGHT. TEMPERATURES AND HUMIDITY WILL BE ON THE INCREASE AGAIN TODAY... WITH HEAT INDICES SOUTH OF THE INTERSTATE 80 CORRIDOR RANGING FROM 100 TO 105 DEGREES BY MID AFTERNOON. SCATTERED THUNDERSTORMS WILL BE POSSIBLE THIS MORNING OVER EASTERN IOWA. THESE THUNDERSTORMS ARE NOT EXPECTED TO BE SEVERE. THUNDERSTORMS WILL INTENSIFY OR REDEVELOP ACROSS SOUTHERN MINNESOTA AND NORTHERN IOWA LATER THIS AFTERNOON. DEPENDING ON WHERE THESE STORMS FIRE UP...THERE WILL BE THE POTENTIAL FOR THESE STORMS TO THEN MOVE INTO PORTIONS OF THE LOCAL AREA LATER TONIGHT. LATEST INDICATIONS SUGGEST AREAS ALONG AND NORTH OF A LINE FROM CEDAR RAPIDS...TO CLINTON AND STERLING WILL BE MORE FAVORABLE OF EXPERIENCING SOME OF THIS THUNDERSTORM ACTIVITY MAINLY FROM 7 PM CDT TO 1 AM OR SO. WITH THE INCREASING INSTABILITY IN THE AREA...THERE WILL BE A GOOD CHANCE THAT SOME OF THESE STORMS WILL BE SEVERE... PRODUCING DAMAGING STRAIGHT LINE WINDS OF 70 TO 80 MPH...AND LARGE HAIL UP TO THE SIZE OF PING PONG BALLS. CURRENTLY...IT APPEARS THAT AREAS MORE LIKELY TO EXPERIENCING THE HIGHER END WINDS ARE ALONG AND NORTH OF A LINE FROM VINTON...TO ANAMOSA AND MOUNT CARROLL. A BUILDING WARM WEDGE OF AIR ALOFT WILL ACT TO CAP THUNDERSTORM DEVELOPMENT ACROSS MUCH OF IOWA TODAY...AND MAY LIMIT STRONG STORMS FROM MAKING THEIR WAY MUCH SOUTH OF THE INTERSTATE 80 CORRIDOR TONIGHT. THE STORM PREDICTION CENTER HAS OUTLOOKED NORTHEAST IOWA FOR A MODERATE RISK...AND THE REMAINDER OF EAST CENTRAL IOWA...AND NORTHWEST ILLINOIS FOR A SLIGHT RISK OF SEVERE WEATHER THROUGH TONIGHT. A CONFERENCE CALL FOR EMERGENCY MANAGERS WILL BE CONDUCTED LATER THIS MORNING. DETAILS ON THE TIMING OF THIS CALL WILL BE ANNOUNCED BY 9 AM. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY MORE THUNDERSTORMS ARE EXPECTED TO FLARE UP ON THURSDAY SOUTHEAST OF A LINE FROM CARTHAGE...TO PRINCETON ILLINOIS. BUT THE BEST CHANCE OF SEVERE STORMS WILL BE TO THE SOUTHEAST ACROSS CENTRAL ILLINOIS AND EAST CENTRAL MISSOURI. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED BY TONIGHT MAINLY NORTH OF THE INTERSTATE 80 CORRIDOR. ERVIN/12
The Quad Cities radar (KDVN), 141 km away, was scanning. The volume nearest the first event began at 16:56 UTC.
16 thunderstorm wind, 3 heavy rain, 1 lightning, 1 hail. Local standard time, as filed.
estimated 2 inches of rain in 45 minutes; 4 inches of standing water in a parking lot.
Some time between 1045 and 1115 CST lightning struck one of the West Delaware School District buildings and destroyed the phone system.
Civil Defense reported many 1 to 1.5 inch diameter branches down with a few 4 inch diameter branches down.
Thunderstorm winds flattened considerable amounts of corn in fields across the south third of the county. Some of the worst flattening was to the south and east of Ryan according to newspaper reports.
Numerous trees down with one on a mobile home that temporarily trapped a woman inside. The woman was not injured.
Spotter reports estimated 60 mph winds. The emergency manager in Anamosa reported a measured 49 knot (56 mph) wind gust.
1.6 inches of rain in 40 minutes
very large tree down
18 inch diameter tree limbs down
Numerous corn fields were flattened to the north and east of Anamosa by the wind with several trees down. A silo was destroyed 4.4 miles east southeast of Anamosa. Time is estimated based on radar.
dime size hail
Co-op observer reports three farms had tree and crop damage. Corn was flattened with trees downed or topped off.
trees and power lines down
2 to 3 inch diameter branches down
trees and power lines down
4 inch diameter limbs down
1.5 inches of rain
several 12 to 15 inch diameter limbs down with several trees either topped or downed. The smokestacks from the Clinton Showboat Theater were blown off.
co-op observer reports estimated 52 knot (60 mph winds)
trees and power lines down near Northwest Blvd.
trees and power lines down
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2006Every state in 2006This day in weather historyWarnings in Iowa, July 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: 5526490, 5526491, 5526492, 5526493, 5526494, 5526496, 5526497, 5526498, 5526499, 5526495, 5526500, 5526502, 5526501, 5526535, 5526534, 5526536, 5526539, 5526538, 5526540, 5526541, 5526537.