Alert archive / South Dakota / Tornado Warnings in 1987

Tornado Warning 6, NWS Sioux Falls, SD

July 7, 1987Union County, South Dakota

NWS Sioux Falls, SD issued this tornado warning at Jul 7, 1987, 1:01 AM CDT for Union County, South Dakota. It was in force for 29 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
Jul 7, 1987, 1:01 AM CDT (06:01 UTC)
Expired
Jul 7, 1987, 1:30 AM CDT
In force
29 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Union County, SD

The radar

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

What was reported inside it

TimeReportWhereRemark
Jul 7, 1:10 AM CDTTornado F2Union, 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

Omaha, NE (KOAX), launched 00:00Z, 6.0 hours before the alert went out and 170 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, Omaha, NE at 00:00Z on 1987-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Omaha, NE at 00:00Z on 1987-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3581 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
112 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 KSUX 070601
TORSUX
SDC127-070630-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX CITY IA
101 AM CDT TUE JUL 7 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING
EFFECTIVE UNTIL  130 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTHEAST SOUTH DAKOTA
          ...NORTHERN UNION
 
AT 1257 AM CDT A TORNADO WAS REPORTED ON THE GROUND 3 MILES NORTH OF
ALCESTER...ABOUT 40 MILES NORTHWEST OF SIOUX CITY.  NO MOVEMENT WAS
REPORTED BUT THE ASSOCIATED THUNDERSTORMS WERE MOVING EAST AT 30
MILES AN HOUR.
 
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 AVAILAB\LE...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.
SHERLIN

What forecasters said that day

The local office's own words before this tornado 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, Jul 6, 10:31 PM CDT, 2 hours 30 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1030 PM CDT MON JUL 6 1987

AT 1030 PM CDT INTENSE THUNDERSTORMS WITH VERY HEAVY RAIN
CONTINUED ACROSS A LARGE PORTION OF SOUTHEAST SOUTH DAKOTA.

THE STORMS EXTENDED FROM 40 MILES SOUTHWEST OF SIOUX FALLS...NEAR
FREEMAN TO 35 MILES NORTH OF SIOUX FALLS...NEAR MADISON.
THE STRONGEST THUNDERSTORMS WERE LOCATED BETWEEN BRIDGEWATER
AND HOWARD.

THESE THUNDERSTORMS ARE CAPABLE OF PRODUCING VERY HEAVY RAIN THAT
COULD FLOOD LOW LYING AREAS...HAIL...DANGEROUS LIGHTNING...AND
STRONG WINDS OF 40 TO 50 MILES AN HOUR AS THEY MOVE EAST AT 20 MILES
AN HOUR.

PERSONS IN THE SOUTH DAKOTA COUNTIES OF HUTCHINSON...MCCOOK...LAKE
...MINNEHAHA INCLUDING THE COMMUNITIES OF FREEMAN...BRIDGEWATER...
SALEM AND SIOUX FALLS SHOULD BE ON THE LOOKOUT FOR THESE STORMS
UNTIL MIDNIGHT.

STAY TUNED TO YOUR LOCAL RAIO AND TV STATION FOR FURTHER STATEMENTS
OR POSSIBLE WARNINGS.
BUSS
Special weather statement, Jul 6, 11:42 PM CDT, 1 hour 19 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1140 PM CDT MON JUL 6 1987

...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 4 AM CDT FOR EXTREME
SOUTHEAST SOUTH DAKOTA...SOUTHWEST MINNESOTA AND NORTHWEST IOWA...

AT 1135 PM CDT RADAR INDICATED A LINE OF INTENSE THUNDERSTORMS
FROM NEAR PIPESTONE MINNESOTA SOUTHWEST THROUGH SIOUX FALLS
TO YANKTON SOUTH DAKOTA AND INTO NORTHEAST NEBRASKA.

THE HEAVIEST THUNDERSTORMS WERE LOCATED 15 MILES NORTHEAST OF
SIOUX FALLS NEAR GARRETSON...10 MILES SOUTHWEST OF SIOUX FALLS
NEAR LENNOX...15 MILES NORTHEAST OF YANKTON AND JUST SOUTH OF
FREEMAN SOUTH DAKOTA.

THSE THUNDERSTORMS ARE CAPABLE OF PRODUCING STRONG GUSTY WINDS...
SMALL HAIL...HEAVY RAINS AND DANGEROUS CLOUD TO GROUNG LIGHTNING.
THIS LINE OF STORMS WAS MOVING EAST AT 20 MPH AND WILL BE AFFECTING
CLAY AND LINCOLN COUNTIES OF SOUTH DAKOTA...ROCK COUNTY OF SOUTHWEST
MINNESOTA AND LYON COUNTY OF NORTHWEST IOWA BY 1P230 AM CDT.

PERSON ACROSS SOUTHEAST SOUTH DAKOTA...NORTHWEST IOWA AND SOUTHWEST
MINNESOTA SHOULD KEEP ABREAST OF THIS WEATHER SITUATION AND BE
PREPARED TO SEEK SHELTER IF A WARNING IS ISSUED.
JANSEN
Local storm report, Jul 7, 12:22 AM CDT, 39 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 PM CDT TUE JUL 7 1987

949 PM CDT   PEA SIZE HAIL AND HEAVY RAIN NEAR MITCHELL SOUTH DAKOTA.
             (DAVISON COUNTY)

1007 PM CDT  GUST TO 41 MPH AT THE SIOUX FALLS AIRPORT.
             (MINNEHAHA COUNTY)

1155 PM CDT  52 MPH WINDS AT VERMILLION SOUTH DAKOTA.
             (CLAY COUNTY)

1217 AM CDT  PEA TO MARBLE SIZE HAIL COVERING GROUND AT BERESFORD
             SOUTH DAKOTA. (pLINCOLN COUNTY)

JANSEN
Local storm report, Jul 7, 12:23 AM CDT, 38 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 AM CDT TUE JUL 7 1987

949 PM CDT   PEA SIZE HAIL AND HEAVY RAIN NEAR MITCHELL SOUTH DAKOTA.
             (DAVISON COUNTY)

1007 PM CDT  GUST TO 41 MPH AT THE SIOUX FALLS AIRPORT.
             (MINNEHAHA COUNTY)

1155 PM CDT  52 MPH WINDS AT VERMILLION SOUTH DAKOTA.
             (CLAY COUNTY)

1217 AM CDT  PEA TO MARBLE SIZE HAIL COVERING GROUND AT BERESFORD
             SOUTH DAKOTA. (qLINCOLN COUNTY)

JANSEN
Special weather statement, Jul 7, 12:45 AM CDT, 16 minutes before
^DSMSPSSUX
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
1243 AM CDT TUE JUL 7 1987

...VERU STRONG THUNDERSTORMS MOVING ACROSS UNION COUNTY SOUTH DAKOTA...

AT 1240 AM CDT RADAR INDICATED VERY STRONG THUNDERSTORMS MOVING ACROSS
UNION COUNTY SOUTH DAKOTA...ABOUT 20 TO 45 MILES NORTHWEST OF SIOUX
CITY.  THESE THUNDERSTORMS WERE MOVING EAST AT 30 MILES AN HOUR.

THESE THUNDERSTORMS WILL PRODUCE PEA TO MARBLE SIZE HAIL...HEAVLY RAIN
SHOWER AND STRONG GUSTY WINDS.  RESIDENTS OF UNION COUNTY SOUTH DAKOTA
SHOULD BE ON THE LOOKOUT FOR ANY SEVERE WEATHER AND TAKE SHELTER
IMMEDIATELY IF IT IS OBSERVED.

SHERLIN
Special weather statement, Jul 7, 12:56 AM CDT, 5 minutes before
^DSMSPSSUX
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
1255 AM CDT TUE JUL 7 1987

...VERY STRONG THUNDERSTORMS MOVING INTO WESTERN IOWA...

AT 1250 AM CDT RADAR INDICATED A LINE OF VERY STRONG THUNDERSTORMS WAS
MOVING INTO WESTERN IOWA.  THESE STORMS EXTENDED ALL THE WAY FROM THE
EXTREME NORTHWEST CORNER OF IOWA SOUTHWARD INTO MONONA COUNTY...ABOUT
45 MILES SOUTHEAST OF SIOUX CITY.

THESE THUNDERSTORMS WILL PRODUCE PEA TO MARBLE SIZE HAIL.  WIND GUSTS
TO AROUND 50 MILES AN HOUR...DANGEROUS LIGHTNING AND HEAVY SHOWERS.
RESIDENTS OF SIOUX...PLYMOUTH...WOODBURY AND MONONA COUNTIES IN WESTERN
IOWA SHOULD BE ON THE LOOKOUT FOR THESE VERY STRONG STORMS AND TAKE
SHTELTER IF SEVERE WEATHER IS OBSERVED.

SHERLIN

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 6, 7:12 PM CDTTornado WarningFSDBrule48 min
Jul 6, 7:55 PM CDTSevere Thunderstorm WarningFSDAurora65 min
Jul 6, 9:34 PM CDTSevere Thunderstorm WarningFSDDavison26 min
Jul 6, 10:12 PM CDTSevere Thunderstorm WarningFSDLake, McCook48 min
Jul 7, 12:33 AM CDTSevere Thunderstorm WarningFSDLincoln37 min

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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.