Alert archive / Iowa / Tornado Warnings in 2001
Tornado Warning 12, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at Apr 30, 2001, 7:59 PM CDT for Woodbury County, Iowa. It was in force for 31 min. 1 report came from inside the area while it was in force.
The area
The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.
The facts
- Issued
- Apr 30, 2001, 7:59 PM CDT (00:59 UTC)
- Expired
- Apr 30, 2001, 8:30 PM CDT
- In force
- 31 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Woodbury County, IA
The radar
The Omaha radar (KOAX), 107 km from the middle of the area, began a volume at 00:59 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 |
|---|---|---|---|
| Apr 30, 7:59 PM CDT | Tornado F0 | Sloan, IA | A tornado was observed by National Weather Service trained spotters and law enforcement officials. The tornado caused no reported damage. |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.0 hours before the alert went out and 107 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
- 1160 J/kg
- Mixed-layer CIN
- -37 J/kg
- Mixed-layer LCL
- 1364 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 142 m²/s²
- 0-3 km storm-relative helicity
- 241 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 5.3
The text
As transmitted, in the capitals the NWS used until 2016.
000 WFUS53 KFSD 010100 CCA TORFSD IAC193-010130- BULLETIN - EAS ACTIVATION REQUESTED...CORRECTED AREA... TORNADO WARNING NATIONAL WEATHER SERVICE SIOUX FALLS SD 759 PM CDT MON APR 30 2001 THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A * TORNADO WARNING FOR... SOUTHERN WOODBURY COUNTY IN NORTHWEST IOWA * UNTIL 830 PM CDT * AT 759 PM CDT...A TORNADO WAS REPORTED 3 MILES EAST OF SLOAN...OR ABOUT 22 MILES SOUTHEAST OF SIOUX CITY...MOVING EAST AT 15 MPH. * THE TORNADO WILL BE NEAR... HORNICK AROUND 805 PM CDT SMITHLAND AROUND 830 PM CDT A TRAINED WEATHER SPOTTER REPORTED A TORNADO EAST OF SLOAN AT 758 PM CDT. IF YOU ARE IN THE PATH OF THIS TORNADO...TAKE COVER IMMED<IATELY. LAT...LON 4228 9624 4222 9628 4222 9584 4228 9580
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 30, 7:01 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 44 min |
| Apr 30, 7:05 PM CDT | Severe Thunderstorm Warning | FSD | Lyon | 25 min |
| Apr 30, 7:19 PM CDT | Severe Thunderstorm Warning | FSD | Sioux | 26 min |
| Apr 30, 7:24 PM CDT | Severe Thunderstorm Warning | FSD | Osceola | 36 min |
| Apr 30, 7:28 PM CDT | Severe Thunderstorm Warning | FSD | Lyon | 32 min |
| Apr 30, 7:47 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 43 min |
| May 1, 2:28 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 32 min |
| May 1, 2:58 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 47 min |
| May 1, 3:51 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista | 24 min |
| May 1, 4:08 PM CDT | Severe Thunderstorm Warning | FSD | Clay | 22 min |
Nearby
Tornado Warnings in Iowa, 2001Every tornado warning in 2001Tornadoes in 2001
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.