Alert archive / Iowa / Severe Thunderstorm Warnings in 2004
Severe Thunderstorm Warning 307, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Jul 21, 2004, 2:31 AM CDT for Winnebago County, Iowa. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jul 21, 2004, 2:31 AM CDT (07:31 UTC)
- Expired
- Jul 21, 2004, 3:00 AM CDT
- In force
- 29 min
- Issued by
- NWS Des Moines, IA
- Area
- Counties, with a storm outline in the text
County Winnebago County, IA
The radar
The Minneapolis radar (KMPX), 163 km from the middle of the area, began a volume at 07:34 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
Did it verify
Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The nearest sounding before it
Minneapolis, MN (KMPX), launched 00:00Z, 7.5 hours before the alert went out and 162 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1847 J/kg
- Mixed-layer CIN
- -23 J/kg
- Mixed-layer LCL
- 1144 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 13 m²/s²
- 0-3 km storm-relative helicity
- 66 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS53 KDMX 210731 SVRDMX IAC189-210800- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE DES MOINES IA 231 AM CDT WED JUL 21 2004 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... WINNEBAGO COUNTY IN NORTH CENTRAL IOWA * UNTIL 300 AM CDT * AT 228 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM OVER THOMPSON...OR ABOUT 33 MILES WEST OF MASON CITY...MOVING EAST AT 35 MPH. * THE SEVERE THUNDERSTORM WILL BE... NEAR LELAND AROUND 240 AM CDT AND 6 MILES SOUTH OF LAKE MILLS AROUND 250 AM CDT. VERY STRONG WINDS UP TO 60 MPH ARE LIKELY IN THE WARNED AREA. MOVE TO AN INTERIOR ROOM AND STAY AWAY FROM WINDOWS. IF YOU LIVE IN A MOBILE HOME...SEEK SHELTER IN A STURDY BUILDING. LAT...LON 4348 9392 4326 9393 4326 9353 4349 9351 $$ KULA
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
Hazardous weather outlook, Jul 20, 1:20 PM CDT, 13 hours 11 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 120 PM CDT TUE JUL 20 2004 IAZ004>007-015>017-023>028-033>039-048>050-211100- BLACK HAWK-BREMER-BUTLER-CALHOUN-CERRO GORDO-EMMET-FRANKLIN-GRUNDY- HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-MARSHALL-PALO ALTO- POCAHONTAS-SAC-STORY-TAMA-WEBSTER-WINNEBAGO-WORTH-WRIGHT- 120 PM CDT TUE JUL 20 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN PORTIONS OF MID IOWA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER SOUTHEASTERN SOUTH DAKOTA THIS AFTERNOON AND EARLY EVENING. THE STORMS WILL MOVE EAST AND MOVE INTO THE ESTHERVILLE AND SAC CITY AREAS AFTER 7 PM AND SPREAD AS FAR EAST AS THE WATERLOO AND TAMA AREAS AFTER MIDNIGHT. SOME OF THE STORMS MAY BE SEVERE WITH HAIL OF UP TO 2 INCHES IN DIAMETER AND WINDS UP TO 60 MPH. A FEW TORNADOES ARE POSSIBLE...ESPECIALLY DURING THE EVENING HOURS. THE GREATEST RISK FOR SEVERE WEATHER WILL BE ALONG AND NORTH OF HIGHWAY 20. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE IS A SLIGHT RISK OF SEVERE WEATHER WEDNESDAY AFTERNOON AND NIGHT. A FRONTAL SYSTEM WILL PUSH SOUTH INTO THE AREA AND AID IN THUNDERSTORM DEVELOPMENT DURING MAXIMUM HEATING OF THE AFTERNOON AND CONTINUE INTO THE EVENING. DAMAGING WINDS WILL BE THE MAIN THREAT FROM THESE STORMS...WITH A LESSER RISK OF TORNADOES AND HAIL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE AFTER 7 PM TONIGHT...AND AGAIN LATE WEDNESDAY INTO WEDNESDAY NIGHT. IAZ044>047-057>062-070>075-081>086-092>097-211100- ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CARROLL-CASS-CLARKE-CRAWFORD- DALLAS-DAVIS-DECATUR-GREENE-GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA- MARION-MONROE-POLK-POWESHIEK-RINGGOLD-TAYLOR-UNION-WAPELLO-WARREN- WAYNE- 120 PM CDT TUE JUL 20 2004 THIS HAZARDOUS WEATHER OUTLOOK IS SOUTHERN PORTIONS OF MID IOWA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER EASTERN SOUTH DAKOTA LATE THIS AFTERNOON OR EARLY EVENING. A STRONG CAP IS EXPECTED TO BE IN PLACE OVER SOUTHERN IOWA AND AS A RESULT...MOST OF THE THUNDERSTORMS ARE EXPECTED TO REMAIN TO THE NORTH OF THE AREA. THUNDERSTORMS MAY SLIDE SOUTH FROM THE THUNDERSTORM COMPLEX TO THE NORTH AFTER 10 PM TONIGHT. THE MAIN THREAT FROM THESE WILL BE FOR HIGH WINDS UP TO 60 MPH AND HAIL OF THREE QUARTERS OF AN INCH OR LARGER IN DIAMETER. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE IS A SLIGHT RISK OF SEVERE WEATHER WEDNESDAY AFTERNOON AND NIGHT. A FRONTAL SYSTEM WILL PUSH SOUTH INTO THE AREA AND AID IN THUNDERSTORM DEVELOPMENT DURING MAXIMUM HEATING OF THE AFTERNOON AND CONTINUE INTO THE EVENING. DAMAGING WINDS WILL BE THE MAIN THREAT FROM THESE STORMS...WITH A LESSER RISK OF TORNADOES AND HAIL. THERE WILL BE ANOTHER SLIGHT RISK OF SEVERE WEATHER ON THURSDAY AS THE AS THE FRONT CONTINUES TO PUSH THROUGH SOUTHERN IOWA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE AFTER 10 PM TONIGHT...AND AGAIN WEDNESDAY AND THURSDAY. DONAVON
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 5:59 AM CDT | Severe Thunderstorm Warning | DMX | Hamilton, Wright | 46 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 2004Every severe thunderstorm warning in 2004
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.