Hail and Damaging Winds in Iowa, July 19 to 20, 2006

Name: Hail and Damaging Winds in Iowa, July 19 to 20, 2006
Start: 2006-07-19T20:08
End: 2006-07-20T02:05
Location: Iowa

July 19 to 20, 2006 · NWS DMX · 8 events in 6 counties and zones

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $51,000
Crop damage: $30,000
Events: 8

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.

What happened

The episode as NWS DMX wrote it up.

An extremely unstable and hot airmass was in place over Iowa during the day on the 19th. The weather situation was complicated with a warm front extending from northwest into central, into southeast Iowa during the mid afternoon. Earlier in the day, and MCS moved across north central into east central and southeast Iowa. This MCS laid down an outflow boundary that pushed southwest into the state, and eventually met up with the warm front. Along and southwest of the boundary, considerable dew point pooling took place. Afternoon temperatures reached the upper 90s to near 105 with dew points in the upper 70s to mid 80s. CAPE values soared to the 8000 to 10,000 J/kg range by early evening as the lifted index fell to the -10 to -15 C. range. A very strong cap was in place with 700 mb temperatures warming to between +14 and +17 C. The freezing level was unusually high, in the 16,500 to 17,000 foot range. Thunderstorms tried to develop by the early evening, but as additional warmer and drier air pushed into the area the dissipated. After sunset a cluster of thunderstorms developed over southern Minnesota and northern Iowa along the north edge of the cap as a cold front pushed into the state from the northwest. The shear environment was quite favorable with shear in the 55 to 70 kt range in the zero to 6 km layer. The storms eventually developed into an MCC and skirted the northern edge of Iowa. They produced strong winds and some hail. The hail was limited by the very warm airmass with reports of hail in the penny to nickle size range. High winds caused damage to trees and power lines with wind speeds in the 60 to 70 MPH range with the stronger storms in the Winnebago, Worth, and Bremer County areas of north central and northeast Iowa.

What forecasters said that day

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 Des Moines, IA wrote its last area forecast discussion before the first event at Jul 19, 2:35 PM CST, 5 hours 33 minutes earlier.

Area forecast discussion, Jul 19, 2:35 PM CST, 5 hours 33 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
335 PM CDT WED JUL 19 2006

.DISCUSSION...
STRONG CONTRAST OVR STATE TDA WITH OUTFLOW BNDRY PUSHED UP AGNST WRM
FNT ATTM.  AMS CAPPED FOR THE TIME BEING BUT VRY UNSTABLE.  MUCAPE
8000+ NOW WITH MLCAPE NOT MUCH LOWER SO IF ANYTHING CAN GET GOING
WUD GO SVR QUICKLY SIM TO 22 MAY 04 EVENT.  SCNDRY PUSH WL BE WITH
MCS DVLPT OVR NGT ROLLING DOWN THE BOUNDARY.  LATEST TPC SWODY1 FITS
DESCRIPTION WELL.  ACVTY WL BE TO THE S AFT TNGT WITH ONLY CHC FOR
PCPN IN FCST BEING WITH S/WV ON FRI.  NO SVR WX XPCTD WITH THAT SYS
HWVR.  TEMPS WL COOL SIG TO AT TO A LTL BLO NORM FOR A FEW DAYS BFR
SLO WRMG AFT THE WKND.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...HEAT ADVISORY SW HALF OF CWA FROM
17Z-00Z.

Hazardous weather outlook, Jul 19, 1:26 PM CST, 6 hours 42 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
226 PM CDT WED JUL 19 2006

IAZ004>007-015>017-023>028-033>039-047>050-201100-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-
WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-BOONE-STORY-MARSHALL-
TAMA-
226 PM CDT WED JUL 19 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
NORTHERN IOWA...GENERALLY ALONG AND NORTH OF STATE HIGHWAY 30.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE
THIS AFTERNOON AND EVENING OVER NORTHERN IOWA. SUPER CELL
THUNDERSTORMS ARE EXPECTED INITIALLY...WITH ALL MODES OF SEVERE
WEATHER POSSIBLE...INCLUDING HAIL OF GOLF BALL SIZE OR
LARGER...WIND GUSTS OF 60 TO 80 MPH...AND ISOLATED TORNADOES.
STORMS ARE EXPECTED TO EVOLVE INTO A LARGE COMPLEX THAT WILL MOVE
RAPIDLY SOUTHEAST OVER THE AREA DURING THE EVENING...WITH DAMAGING
STRAIGHT LINE WINDS THE MAIN THREAT. STORM INITIATION IS POSSIBLE
BY 4 PM...BUT MORE LIKELY BY 5 OR 6 PM THIS EVENING.

AREAS FROM FORT DODGE TO SAC CITY CAN EXPECT HEAT INDEX VALUES
AROUND 105 DEGREES THIS AFTERNOON INTO EARLY EVENING. SOME RELIEF IS
EXPECTED BY TONIGHT AS A COLD FRONT PUSHES THROUGH CENTRAL IOWA.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

ISOLATED THUNDERSTORMS ARE POSSIBLE ON FRIDAY. NO SEVERE WEATHER
IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY BY LATE AFTERNOON INTO THE EVENING
HOURS...ESPECIALLY BETWEEN 5 AND 10 PM. A CONFERENCE CALL FOR
EMERGENCY MANAGEMENT WILL BE HELD AT 330 PM.

IAZ044>046-057>062-070>075-081>086-092>097-201100-
CRAWFORD-CARROLL-GREENE-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-
POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-
CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-
APPANOOSE-DAVIS-
226 PM CDT WED JUL 19 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTHERN IOWA...GENERALLY SOUTH OF STATE HIGHWAY 30.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON AND
TONIGHT...MAINLY NORTH OF STATE HIGHWAY 34. A FEW SEVERE STORMS
ARE POSSIBLE. THE MAIN THREAT WOULD BE DAMAGING STRAIGHT LINE
WINDS AROUND 70 MPH...MAINLY BETWEEN 7 AND 11 PM THIS EVENING.

AREAS ALONG AND SOUTHWEST OF A LINE FROM AMES THROUGH DES MOINES
TO OTTUMWA...CAN EXPECT HEAT INDEX VALUES FROM 105 TO AROUND 110
DEGREES THIS AFTERNOON INTO EARLY EVENING. SOME RELIEF IS EXPECTED
BY TONIGHT AS A COLD FRONT PUSHES THROUGH CENTRAL IOWA.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

ISOLATED THUNDERSTORMS ARE POSSIBLE ON FRIDAY. NO SEVERE WEATHER IS
EXPECTED AT THIS TIME. A CONFERENCE CALL FOR EMERGENCY MANAGEMENT
WILL BE HELD AT 330 PM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE LATE THIS AFTERNOON THROUGH THE
EVENING HOURS...ESPECIALLY NORTH OF STATE HIGHWAY 34 BETWEEN 7 AND
11 PM.

COGIL/KINNEY

The radar

The Des Moines radar (KDMX), 133 km away, was scanning. The volume nearest the first event began at 02:06 UTC.

Open the radar archive at this moment

Event by event

5 thunderstorm wind, 3 hail. Local standard time, as filed.

Hail, Hancock

When: July 19, 8:08 PM CST
Where: Hancock County, 5 mi S of Corwith
Measured: 0.75 in hail
Crop damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 42.917, -93.967

Thunderstorm Wind, Winnebago

When: July 19, 10:25 PM CST
Where: Winnebago County, Thompson
Measured: 57 kt (66 mph) estimated gust
Property damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.367, -93.783

Thunderstorm Wind, Worth

When: July 19, 10:37 PM CST
Where: Worth County, Hanlontown
Measured: 53 kt (61 mph) measured gust
Property damage: $5,000
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 43.283, -93.383

Thunderstorm Wind, Worth

When: July 19, 10:50 PM CST
Where: Worth County, 2 mi W of Northwood
Measured: 52 kt (60 mph) estimated gust
Property damage: $5,000
Reported by: GENERAL PUBLIC
Coordinates: 43.483, -94.133

Hail, Kossuth

When: July 19, 10:55 PM CST
Where: Kossuth County, 5 mi NNE of Ledyard
Measured: 0.88 in hail
Property damage: $3,000
Crop damage: $5,000
Reported by: GENERAL PUBLIC
Coordinates: 43.433, -93.783

Thunderstorm Wind, Winnebago

When: July 19, 11:15 PM CST
Where: Winnebago County, 5 mi N of Thompson
Measured: 61 kt (70 mph) estimated gust
Property damage: $15,000
Crop damage: $15,000
Reported by: GENERAL PUBLIC
Coordinates: 42.850, -92.100

Thunderstorm Wind, Bremer

When: July 20, 12:12 AM CST
Where: Bremer County, Sumner
Measured: 57 kt (66 mph) estimated gust
Property damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.150, -93.200

Hail, Cerro Gordo

When: July 20, 2:05 AM CST
Where: Cerro Gordo County, Mason City
Measured: 0.88 in hail
Property damage: $3,000
Crop damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.450, -93.250

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Iowa in 2006 Every state in 2006 This day in weather history Warnings in Iowa, July 2006

Sources

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: 5516096, 5516097, 5516098, 5516101, 5516102, 5516103, 5516099, 5516100.