Alert archive / Iowa / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 37, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Jun 20, 1997, 10:34 PM CDT for Lyon County, Iowa. It was in force for 31 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, 10:34 PM CDT (03:34 UTC)
- Expired
- Jun 20, 1997, 11:05 PM CDT
- In force
- 31 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Whole counties
County Lyon County, IA
The radar
The Sioux Falls radar (KFSD), 48 km from the middle of the area, began a volume at 03:36 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 nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 3.6 hours before the alert went out and 230 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
- 5994 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 1151 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 89 m²/s²
- 0-3 km storm-relative helicity
- 186 m²/s²
- Significant tornado parameter
- 4.8
- Supercell composite
- 25.7
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KFSD 210334 RRA SVRFSD IAC119-210405- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE SIOUX FALLS SD 1034 PM CDT FRI JUN 20 1997 * SEVERE THUNDERSTORM WARNING FOR WESTERN LYON COUNTY - IN NORTHWESTERN IOWA * UNTIL 1105 PM CDT * SOME AREAS AFFECTED ALVORD AROUND 1036 PM CDT LARCHWOOD AROUND 1038 PM CDT LESTER AROUND 1040 PM CDT ROCK RAPIDS AROUND 1050 PM CDT * AT 1032 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 19 MILES SOUTHEAST OF SIOUX FALLS OR IN THE VICINITY OF ALVORD MOVING NORTHEAST AT 25 MPH. IF YOU ARE OUTDOORS...MOVE TO A PLACE OF SHELTER IMMEDIATELY IF A STORM APPROACHES. MOTORISTS SHOULD REMAIN ALERT FOR REDUCED VISIBILITIES DURING DOWNPOURS OF RAIN. STREETS MAY FLOOD QUICKLY. HARMON
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 20, 9:06 PM CDT, 1 hour 28 minutes earlier.
Area forecast discussion, Jun 20, 9:06 PM CDT, 1 hour 28 minutes before
SOUTH DAKOTA/NORTHWEST IOWA/SOUTHWEST MINNESOTA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 905 PM CDT FRI JUN 20 1997 GOING INTO SEVERE WEATHER MODE WITH AN ACTIVE WARNING. NO SIGNIFICAN T UPDATE FOR THE CWA FROM EARLIER ZONE FORECASTS. .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, 9:00 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 45 min |
| Jun 20, 9:38 PM CDT | Severe Thunderstorm Warning | FSD | Ida | 47 min |
| Jun 20, 9:45 PM CDT | Severe Thunderstorm Warning | FSD | Woodbury | 35 min |
| Jun 20, 10:27 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 33 min |
| Jun 20, 11:02 PM CDT | Severe Thunderstorm Warning | FSD | Lyon | 33 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.