Alert archive / Iowa / Tornado Warnings in 2004
Tornado Warning 11, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at May 21, 2004, 8:19 PM CDT for Plymouth County, Iowa. It was in force for 41 min. 9 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
- May 21, 2004, 8:19 PM CDT (01:19 UTC)
- Expired
- May 21, 2004, 9:00 PM CDT
- In force
- 41 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Counties, with a storm outline in the text
County Plymouth County, IA
The radar
The Sioux Falls radar (KFSD), 98 km from the middle of the area, began a volume at 01:22 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 |
|---|---|---|---|
| May 21, 8:45 PM CDT | HAIL 0.75 | 6 W Merrill, IA | |
| May 21, 8:45 PM CDT | HAIL 0.75 | 6 W Merrill, IA | |
| May 21, 8:45 PM CDT | HAIL 0.75 | 6 W Merrill, IA | |
| May 21, 9:01 PM CDT | HAIL 2.75 | 4 W Merrill, IA | |
| May 21, 9:01 PM CDT | HAIL 2.75 | 4 W Merrill, IA | |
| May 21, 9:01 PM CDT | HAIL 2.75 | 4 W Merrill, IA | |
| May 21, 9:10 PM CDT | HAIL 0.75 | Le Mars, IA | |
| May 21, 9:10 PM CDT | HAIL 0.75 | Le Mars, IA | |
| May 21, 9:10 PM CDT | HAIL 0.75 | Le Mars, IA |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.3 hours before the alert went out and 158 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
- 2589 J/kg
- Mixed-layer CIN
- -33 J/kg
- Mixed-layer LCL
- 1462 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 166 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 6.9
The text
As transmitted, in the capitals the NWS used until 2016.
293
WFUS53 KFSD 220119
TORFSD
IAC149-220200-
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
819 PM CDT FRI MAY 21 2004
THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A
* TORNADO WARNING FOR...
PLYMOUTH COUNTY IN NORTHWEST IOWA
* UNTIL 900 PM CDT
* AT 819 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 10 MILES
SOUTHWEST OF AKRON...OR ABOUT 10 MILES NORTH OF PONCA...MOVING EAST
AT 35 MPH.
* THE TORNADO WILL BE NEAR...
AKRON AROUND 825 PM CDT
MERRILL AROUND 850 PM CDT
LE MARS AROUND 855 PM CDT
IF YOU ARE IN THE PATH OF THIS STORM...TAKE COVER IMMEDIATELY.
THIS STORM WILL ALSO LARGE HAIL UP TO GOLF BALL SIZE.
A TORNADO WATCH REMAINS IN EFFECT UNTIL 100 AM CDT SATURDAY MORNING
FOR SOUTHEASTERN SOUTH DAKOTA. A TORNADO WATCH ALSO REMAINS IN EFFECT
UNTIL 1000 PM CDT FRIDAY EVENING FOR NORTHWEST IOWA.
LAT...LON 4265 9645 4269 9663 4278 9663 4290 9650
4286 9613 4264 9610
$$
JRMThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 21, 8:37 PM CDT | Severe Thunderstorm Warning | FSD | Clay, O'Brien | 23 min |
| May 21, 8:56 PM CDT | Tornado Warning | FSD | Plymouth | 49 min |
| May 21, 9:25 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee | 35 min |
| May 21, 9:33 PM CDT | Severe Thunderstorm Warning | FSD | Clay | 27 min |
| May 21, 9:33 PM CDT | Severe Thunderstorm Warning | FSD | O'Brien | 42 min |
| May 21, 9:59 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Woodbury | 31 min |
| May 21, 10:12 PM CDT | Severe Thunderstorm Warning | FSD | Clay | 33 min |
| May 21, 10:14 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 31 min |
| May 21, 10:29 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista | 16 min |
| May 21, 11:07 PM CDT | Severe Thunderstorm Warning | FSD | Ida, Woodbury | 23 min |
| May 21, 11:50 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 25 min |
| May 22, 12:03 AM CDT | Flash Flood Warning | FSD | Cherokee, Clay, O'Brien, Plymouth | 87 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.