Alert archive / South Dakota / Severe Thunderstorm Warnings in 1986

Severe Thunderstorm Warning 199, NWS Sioux Falls, SD

September 24, 1986Mellette County, Todd County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Sep 24, 1986, 8:12 PM CDT for Mellette County, Todd County, South Dakota. It was in force for 63 min.

The area

The counties it named.

The facts

Issued
Sep 24, 1986, 8:12 PM CDT (01:12 UTC)
Expired
Sep 24, 1986, 9:15 PM CDT
In force
63 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Mellette County, SD, Todd 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

Rapid City, SD (KRAP), launched 00:00Z, 1.2 hours before the alert went out and 188 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, Rapid City, SD at 00:00Z on 1986-09-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1041 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, Rapid City, SD at 00:00Z on 1986-09-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 217 square meters per square second.1939587897117Sfc1 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
1041 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
1234 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
217 m²/s²
0-3 km storm-relative helicity
297 m²/s²
Significant tornado parameter
0.9
Supercell composite
6.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFSD 250112
SVRFSD
SDC095-121-250215-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
812 PM CDT WED SEP 24 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 915 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTIES OF

SOUTH CENTRAL SOUTH DAKOTA...EASTERN MELLETTE AND EASTERN TODD

SOME OF THE CITIES INCLUDED IN THIS WARNING ARE MISSION AND
WHITE RIVER.

AT 805 PM CDT  RADAR INDICATED A SEVERE THUNDERSTORM NEAR
MISSION SOUTH DAKOTA OR ABOUT 25 MILES NORTH OF VALENTINE
NEBRASKA MOVING TO THE NORTH NORTHEAST AT 40 MPH.

 AT 753 PM CDT A TORNADO TOUCHED DOWN ABOUT 1/2 MILE EAST
OF CIDER BUTTE IN WESTERN MELLETTE COUNTY FROM A DIFFERENT
STORM.

IF YOU ARE IN THE PATH OF THIS STORM..YOU SHOULD GET TO A REINFORCED
SHELTER. A SEVERE THUNDERSTORM PRODUCES DAMAGING WINDS IN EXCESS OF
60 MPH..HAIL 3/4 INCH OR LARGER..DEADLY LIGHTNING..AND HEAVY RAIN
THAT CAN QUICKLY FLOOD A LOW LYING AREA.

THESE STORMS CAN AND OCCASIONALLY DO PRODUCE A TORNADO WITH LITTLE OR
NO ADVANCE WARNING SO BE ON THE LOOKOUT.

KOSCIELSKI

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, Sep 24, 7:51 PM CDT, 21 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE HURON SD
740 PM CDT WED SEP 24 1986

...TORNADO WATCH FOR WESTERN SOUTH DAKOTA UNTIL MIDNIGHT CDT...

AT 730 PM CDT...SCATTERED THUNDERSTORMS...SOME WITH VERY HEAVY RAIN...
HAD DEVELOPED IN SOUTH CENTRAL SOUTH DAKOTA...IN A 20 MILE WIDE BAND
FROM JUST EAST OF RAPID CITY TO 60 MILES WEST OF WINNER.

THE STRONGEST THUNDERSTORM WAS LOCATED IN SOUTHWEST MELLETTE COUNTY...
50 MILES WEST OF WINNER...MOVING NORTH AT 35 MILES AN HOUR. PERSONS IN
THE PATH OF THIS STORM SHOULD REMAIN ALERT AND BE PREPARED TO SEEK
SHELTER IF THREATENING WEATHER APPROACHES.

ALSO...SCATTERED THUNDERSHOWERS AND RAINSHOWERS CONTINUED IN NOeRTHEAST
SOUTH DAKOTA...NORTH OF A LINE FROM MOBRIDGE TO 50 MILES SOUTHEAST OF
WATERTOWN.  MOVEMENT WAS NORTH AT 35 MILES AN HOUR.
STOREY
Local storm report, Sep 24, 8:00 PM CDT, 12 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
757 PM CDT WED SEP 25 1986

TORNADO ON GROUND FOR COUPLE OF MINUTES 1/2 MILE E OF CIDER BUTTE
AT 753 PM CDT..ABOUT 15 MILES WEST OF WHITE RIVER IN MELLqETTE COUNTY.

KOSCIELSK

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 24, 7:15 PM CDTSevere Thunderstorm WarningFSDMellette, Todd60 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 1986Every severe thunderstorm warning in 1986

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.