Alert archive / Iowa / Tornado Warnings in 2004
Tornado Warning 54, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at Jul 31, 2004, 8:30 PM CDT for Lyon County, Iowa. It was in force for 30 min. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Jul 31, 2004, 8:30 PM CDT (01:30 UTC)
- Expired
- Jul 31, 2004, 9:00 PM CDT
- In force
- 30 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Counties, with a storm outline in the text
County Lyon County, IA
The radar
The Sioux Falls radar (KFSD), 64 km from the middle of the area, began a volume at 01:30 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 31, 8:45 PM CDT | HAIL 1.75 | 1 N George, IA | |
| Jul 31, 9:00 PM CDT | HAIL 0.75 | 2 Sw Little Rock, IA |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jul 31, 3:00 PM CDT | Tornado Watch | SPC | 7 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.5 hours before the alert went out and 235 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
- 1429 J/kg
- Mixed-layer CIN
- -97 J/kg
- Mixed-layer LCL
- 1769 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 94 m²/s²
- 0-3 km storm-relative helicity
- 282 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 6.7
The text
As transmitted, in the capitals the NWS used until 2016.
000 WFUS53 KFSD 010130 TORFSD IAC119-010200- BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE SIOUX FALLS SD 829 PM CDT SAT JUL 31 2004 THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A * TORNADO WARNING FOR... EASTERN LYON COUNTY IN NORTHWEST IOWA * UNTIL 900 PM CDT * AT 829 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 3 MILES WEST OF LITTLE ROCK...OR ABOUT 11 MILES EAST OF ROCK RAPIDS...MOVING SOUTH AT 10 MPH. * THE TORNADO WILL BE NEAR... GEORGE AROUND 850 PM CDT THIS WARNING EXTENDS THE TORNADO WARNING PREVIOUSLY ISSUED FOR THE WARNED AREA. THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. TAKE COVER NOW. LAT...LON 4350 9588 4350 9610 4328 9610 4328 9588 $$ JH
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 31, 7:59 PM CDT | Tornado Warning | FSD | Lyon | 31 min |
| Jul 31, 8:01 PM CDT | Tornado Warning | FSD | Lyon | 29 min |
| Jul 31, 8:11 PM CDT | Severe Thunderstorm Warning | FSD | Osceola | 34 min |
| Jul 31, 8:58 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Osceola | 32 min |
| Jul 31, 9:48 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Osceola | 27 min |
| Jul 31, 9:49 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth, Sioux | 41 min |
| Jul 31, 10:08 PM CDT | Severe Thunderstorm Warning | FSD | Clay, O'Brien | 22 min |
| Jul 31, 10:30 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Clay, O'Brien | 30 min |
| Jul 31, 10:44 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Sioux | 31 min |
| Jul 31, 10:56 PM CDT | Flash Flood Warning | FSD | O'Brien | 2 hr |
| Jul 31, 11:01 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Clay, O'Brien | 14 min |
| Jul 31, 11:03 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Clay, O'Brien | 27 min |
| Jul 31, 11:13 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee | 32 min |
| Jul 31, 11:32 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 28 min |
| Jul 31, 11:43 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee | 32 min |
| Aug 1, 12:16 AM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida | 44 min |
Nearby
Tornado Warnings in Iowa, 2004Every tornado warning in 2004Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.