Alert archive / South Dakota / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 4, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at May 12, 1991, 4:51 PM CDT for Brule County, South Dakota. It was in force for 39 min. 1 report came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- May 12, 1991, 4:51 PM CDT (21:51 UTC)
- Expired
- May 12, 1991, 5:30 PM CDT
- In force
- 39 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Whole counties
County Brule County, SD
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 12, 4:52 PM CDT | Hail 0.75 | Brule, SD |
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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Aberdeen, SD (KHON), launched 12:00Z, 9.9 hours before the alert went out and 142 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
- 1568 J/kg
- Mixed-layer CIN
- -122 J/kg
- Mixed-layer LCL
- 816 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 49 m²/s²
- 0-3 km storm-relative helicity
- 49 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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.
In the hours before
Special weather statement, May 12, 3:37 PM CDT, 1 hour 14 minutes before
SDZ016-019-122200- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX FALLS SD 335 PM CDT SUN MAY 12 1991 ...TORNADO WATCH TIL 9 PM CDT FOR LARGE PART OF CENTRAL AND EASTERN SOUTH DAKOTA... A TORNADO WATCH IS IN EFFECT FOR A LARGE PART OF CENTRAL AND EASTERN SOUTH DAKOTA. AT 330 PM A LINE OF INTENSE THUNDERSTORMS WITH VERY HEAVY RAIN AND POSSIBLE HAIL WAS DEVELOPING FROM 40 MILES NORTH OF WINNER TO 20 MILES EAST OF WINNER. THE STRONGEST OF THESE STORMS WAS 20 MILES EAST OF WINNER NEAR LAKE BURCH. THE STORMS WERE MOVING TO THE NORTH NORTHEAST AT 30 MPH. PEOPLE IN EASTERN STANLEY...WESTERN BRULE...GREGORY AND NORTHWEST CHARLES MIX COUNTY SHOULD REMAIN ALERT TO THE POSSIBILITY OF SEVERE WEATHER. BIER
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 12, 3:59 PM CDT | Severe Thunderstorm Warning | FSD | Brule | 46 min |
| May 12, 5:41 PM CDT | Severe Thunderstorm Warning | FSD | Douglas | 34 min |
| May 12, 6:56 PM CDT | Tornado Warning | FSD | Hanson | 34 min |
| May 12, 6:58 PM CDT | Tornado Warning | FSD | Hanson | 32 min |
Nearby
Severe Thunderstorm Warnings in South Dakota, 1991Every severe thunderstorm warning in 1991
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.