Alert archive / South Dakota / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 347, NWS Sioux Falls, SD

August 20, 2002Aurora County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 20, 2002, 7:25 PM CDT for Aurora County, South Dakota. It was in force for 35 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 20, 2002, 7:25 PM CDT (00:25 UTC)
Expired
Aug 20, 2002, 8:00 PM CDT
In force
35 min
Issued by
NWS Sioux Falls, SD
Area
Counties, with a storm outline in the text

County Aurora County, SD

The radar

The Sioux Falls radar (KFSD), 143 km from the middle of the area, began a volume at 00:24 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.

What was reported inside it

TimeReportWhereRemark
Aug 20, 7:32 PM CDTHail 0.75Plankinton, SD
Aug 20, 7:57 PM CDTHail 0.75Mt Vernon, 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 20, 2:35 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 0.4 hours before the alert went out and 121 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 2002-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 00:00Z on 2002-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.19395878Sfc1 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
1 J/kg
Mixed-layer CIN
-265 J/kg
Mixed-layer LCL
857 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
256 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

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

897 
WUUS53 KFSD 210025
SVRFSD
SDC003-210100-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
725 PM CDT TUE AUG 20 2002

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  AURORA COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 800 PM CDT

* AT 725 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 8 MILES NORTH OF PLANKINTON...OR ABOUT 21 MILES
  WEST OF MITCHELL...MOVING EAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
RURAL AURORA COUNTY THROUGH 740 PM CDT

THIS STORM WILL PRODUCE LARGE HAIL. GO INSIDE A STURDY BUILDING AND
STAY AWAY FROM WINDOWS.

LAT...LON 4389 9858 4368 9860 4368 9833 4393 9834

BOUSTEAD

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 7:17 PM CDTSevere Thunderstorm WarningFSDDavison, Sanborn43 min
Aug 20, 7:48 PM CDTSevere Thunderstorm WarningFSDGregory42 min
Aug 20, 8:25 PM CDTSevere Thunderstorm WarningFSDHanson50 min
Aug 20, 8:31 PM CDTSevere Thunderstorm WarningFSDDavison29 min
Aug 20, 8:47 PM CDTSevere Thunderstorm WarningFSDLake, Miner43 min
Aug 20, 9:02 PM CDTSevere Thunderstorm WarningFSDMcCook43 min
Aug 20, 9:10 PM CDTTornado WarningFSDHanson35 min
Aug 20, 9:10 PM CDTTornado WarningFSDHanson35 min
Aug 20, 9:17 PM CDTSevere Thunderstorm WarningFSDAurora43 min
Aug 20, 9:25 PM CDTSevere Thunderstorm WarningFSDDouglas50 min
Aug 20, 9:42 PM CDTFlash Flood WarningFSDAurora, Davison108 min
Aug 20, 9:42 PM CDTSevere Thunderstorm WarningFSDMinnehaha63 min
Aug 20, 9:44 PM CDTSevere Thunderstorm WarningFSDMcCook46 min
Aug 20, 10:11 PM CDTSevere Thunderstorm WarningFSDHutchinson49 min
Aug 21, 7:46 AM CDTFlash Flood WarningFSDMinnehaha119 min
Aug 21, 6:54 PM CDTSevere Thunderstorm WarningFSDGregory51 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2002Every severe thunderstorm warning in 2002

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; radar from the NEXRAD Level II archive.