Alert archive / South Dakota / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 245, NWS Sioux Falls, SD

August 9, 2002Aurora County, Sanborn County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 9, 2002, 5:56 PM CDT for Aurora County, Sanborn County, South Dakota. It was in force for 34 min. 4 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 9, 2002, 5:56 PM CDT (22:56 UTC)
Expired: Aug 9, 2002, 6:30 PM CDT
In force: 34 min
Issued by: NWS Sioux Falls, SD
Area: Counties, with a storm outline in the text

Counties Aurora County, SD, Sanborn County, SD

The radar

The Sioux Falls radar (KFSD), 127 km from the middle of the area, began a volume at 23:00 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

Time	Report	Where
Aug 9, 5:57 PM CDT	Hail 0.88	Storla, SD
Aug 9, 6:09 PM CDT	Hail 1	Letcher, SD
Aug 9, 6:09 PM CDT	Thunderstorm Wind 52 E	Letcher, SD
Aug 9, 6:15 PM CDT	Hail 0.75	Letcher, 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.

Issued	Product	Office	Lasted
Aug 9, 5:35 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 10.9 hours before the alert went out and 106 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 20 J/kg
Mixed-layer CIN: -386 J/kg
Mixed-layer LCL: 1144 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: -1 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.

761 
WUUS53 KFSD 092256
SVRFSD
SDC003-111-092330-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
555 PM CDT FRI AUG 9 2002

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SANBORN COUNTY IN EAST CENTRAL SOUTH DAKOTA
  NORTHEAST AURORA COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 630 PM CDT

* AT 555 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
  SEVERE THUNDERSTORM 11 MILES WEST OF LETCHER...OR ABOUT 21 MILES 
  NORTHWEST OF MITCHELL...MOVING NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  LETCHER AROUND 610 PM CDT
  FORESTBURG AROUND 615 PM CDT
  ARTESIAN AROUND 630 PM CDT

AT 543 PM CDT...60 MPH WINDS WERE REPORTED 5 MILES NORTHWEST OF 
STORLA...WITH 5 INCH DIAMETER TREE BRANCHES DOWN.

THIS STORM HAS A HISTORY OF PRODUCING DAMAGING WIND. GO INSIDE A
STURDY BUILDING AND STAY AWAY FROM WINDOWS.

LAT...LON 4394 9841 4381 9840 4396 9783 4417 9796
          4393 9834

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 5:23 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Jerauld	22 min
Aug 9, 5:27 PM CDT	Severe Thunderstorm Warning	FSD	Gregory	33 min
Aug 9, 5:59 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix, Gregory	46 min
Aug 9, 6:11 PM CDT	Tornado Warning	FSD	Davison, Sanborn	34 min
Aug 9, 6:46 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix, Gregory	44 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2002 Every 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.