Alert archive / South Dakota / Tornado Warnings in 1987

Tornado Warning 1, NWS Sioux Falls, SD

May 20, 1987Bon Homme County, South Dakota

NWS Sioux Falls, SD issued this tornado warning at May 20, 1987, 7:46 PM CDT for Bon Homme County, South Dakota. It was in force for 29 min.

The area

The counties it named.

The facts

Issued
May 20, 1987, 7:46 PM CDT (00:46 UTC)
Expired
May 20, 1987, 8:15 PM CDT
In force
29 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Bon Homme County, SD

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Aberdeen, SD (KHON), launched 00:00Z, 0.8 hours before the alert went out and 217 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.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 00:00Z on 1987-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 317 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 00:00Z on 1987-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
317 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
1106 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KFSD 210046
TORFSD
SDC009-210115-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
746 PM CDT WED MAY 20 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING
EFFECTIVE UNTIL  815 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTHEAST SOUTH DAKOTA
          ...WESTERN BON-HOMME
 
SOME CITIES INCLUDED IN THIS WARNING PERKINS...AVON AND TYNDALL.
 
AT 745 PM CDT A TORNADO WAS REPORTED 10 TO 14 MILES SOUTH OF
AVON SOUTH DAKOTA IN SOUTHWEST BON HOMME COUNTY MOVING NORTH
NORTHEAST AT 40 MPH.
 
IF YOU ARE IN THE PATH OF A TORNADO...THE SAFEST PLACE IS A
BASEMENT.  GET UNDER A WORKBENCH OR PIECE OF STURDY FURNITURE.
IF NO BASEMENT IS AVAILABLE...SEEK SHELTER IN AN INTERIOR ROOM
SUCH AS A CLOSET ON THE LOWEST FLOOR.  USE BLANKETS...PILLOWS...
OR CUSHIONS TO COVER YOUR BODY.  AVOID WINDOWS.

Nearby

Tornado Warnings in South Dakota, 1987Every tornado warning in 1987Tornadoes in 1987

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.