Alert archive / Iowa / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 30, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Jun 20, 1997, 8:28 AM CDT for O'Brien County, Osceola County, Iowa. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jun 20, 1997, 8:28 AM CDT (13:28 UTC)
- Expired
- Jun 20, 1997, 9:00 AM CDT
- In force
- 32 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Whole counties
Counties O'Brien County, IA, Osceola County, IA
The radar
The Sioux Falls radar (KFSD), 98 km from the middle of the area, began a volume at 13:28 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.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jun 20, 4:15 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 20, 5:00 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 12:00Z, 1.5 hours before the alert went out and 221 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
- 381 J/kg
- Mixed-layer CIN
- -172 J/kg
- Mixed-layer LCL
- 3033 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 129 m²/s²
- 0-3 km storm-relative helicity
- 287 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KFSD 201329 RRA SVRFSD IAC141-143-201400- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE SIOUX FALLS SD 828 AM CDT FRI JUN 20 1997 * SEVERE THUNDERSTORM WARNING FOR NORTHERN O'BRIEN COUNTY - IN NORTHWESTERN IOWA SOUTHERN OSCEOLA COUNTY - IN NORTHWESTERN IOWA * UNTIL 900 AM CDT * SOME AREAS AFFECTED RITTER AROUND 830 AM CDT ASHTON AROUND 830 AM CDT SANBORN AROUND 845 AM CDT MELVIN AROUND 845 AM CDT * AT 826 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 11 MILES SOUTHWEST OF SIBLEY OR 6 MILES NORTHWEST OF RITTER MOVING EAST AT 45 MPH. VERY STONG WINDS IN EXCESS OF 65 MPH CAN BE EXPECTED WITH THIS STORM! IF SEVERE WEATHER IS OBSERVED...CONTACT YOUR LOCAL LAW ENFORCEMENT AGENCY AND ASK THEM TO RELAY YOUR INFORMATION TO THE NATIONAL WEATHER SERVICE. HEITKAMP
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.
NWS Sioux Falls, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 19, 8:29 PM CDT, 11 hours 59 minutes earlier.
Area forecast discussion, Jun 19, 8:29 PM CDT, 11 hours 59 minutes before
SOUTH DAKOTA/NORTHWEST IOWA/SOUTHWEST MINNESOTA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 830 PM CDT WED JUN 18 1997 SEVERE THUNDERSTORM POTENTIAL HAS NOT DEVELOPED AS WELL AS EARLIER EXPECTED AND SOME ADJUSTMENT TO EARLIER CWA ZONES WILL BE MADE. WILL ADJUST ZONES IN LINE WITH SPC CHANGES TO WATCH AREA WHICH IS ANTICIPATED AROUND 9 PM. WILL LOWER THE POPS FOR LATER TONIGHT FOLLOWING THE THUNDERSTORMS MOVING ALONG THE SOUTHEAST BORDER. POTENTIAL FOR SEVERE THUNDERSTORMS YET THROUGH MIDNIGHT FROM AROUND YANKTON ON EAST INTO NORTHWEST IOWA AS THE THUNDERSTORMS MOVE INTO THAT AREA. .FSD...NONE UMLAND
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 20, 2:51 AM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 29 min |
| Jun 20, 3:34 AM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee | 31 min |
| Jun 20, 5:54 AM CDT | Severe Thunderstorm Warning | FSD | Lyon, Sioux | 31 min |
| Jun 20, 6:29 AM CDT | Severe Thunderstorm Warning | FSD | Sioux | 36 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 1997Every severe thunderstorm warning in 1997
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.