Alert archive / South Dakota / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 346, NWS Sioux Falls, SD

August 20, 2002Davison County, Sanborn County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 20, 2002, 7:17 PM CDT for Davison County, Sanborn County, South Dakota. It was in force for 43 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, 7:17 PM CDT (00:17 UTC)
Expired: Aug 20, 2002, 8:00 PM CDT
In force: 43 min
Issued by: NWS Sioux Falls, SD
Area: Counties, with a storm outline in the text

Counties Davison County, SD, Sanborn County, SD

The radar

The Sioux Falls radar (KFSD), 116 km from the middle of the area, began a volume at 00:19 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	Remark
Aug 20, 7:35 PM CDT	Hail 1	Letcher, SD
Aug 20, 8:07 PM CDT	Hail 0.88	Mt 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.

Issued	Product	Office	Lasted
Aug 20, 2:35 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 0.3 hours before the alert went out and 114 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: 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.

682 
WUUS53 KFSD 210017
SVRFSD
SDC035-111-210100-

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

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN SANBORN COUNTY IN EAST CENTRAL SOUTH DAKOTA
  NORTHERN DAVISON COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 800 PM CDT

* AT 717 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 11 MILES EAST OF LETCHER...OR ABOUT 12 MILES
  NORTHEAST OF MITCHELL...MOVING EAST AT 30 MPH.

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

LAT...LON 4396 9833 4374 9833 4385 9796 4386 9786
          4399 9786

BOUSTEAD

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 7:25 PM CDT	Severe Thunderstorm Warning	FSD	Aurora	35 min
Aug 20, 7:48 PM CDT	Severe Thunderstorm Warning	FSD	Gregory	42 min
Aug 20, 8:25 PM CDT	Severe Thunderstorm Warning	FSD	Hanson	50 min
Aug 20, 8:31 PM CDT	Severe Thunderstorm Warning	FSD	Davison	29 min
Aug 20, 8:47 PM CDT	Severe Thunderstorm Warning	FSD	Lake, Miner	43 min
Aug 20, 9:02 PM CDT	Severe Thunderstorm Warning	FSD	McCook	43 min
Aug 20, 9:10 PM CDT	Tornado Warning	FSD	Hanson	35 min
Aug 20, 9:10 PM CDT	Tornado Warning	FSD	Hanson	35 min
Aug 20, 9:17 PM CDT	Severe Thunderstorm Warning	FSD	Aurora	43 min
Aug 20, 9:25 PM CDT	Severe Thunderstorm Warning	FSD	Douglas	50 min
Aug 20, 9:42 PM CDT	Flash Flood Warning	FSD	Aurora, Davison	108 min
Aug 20, 9:42 PM CDT	Severe Thunderstorm Warning	FSD	Minnehaha	63 min
Aug 20, 9:44 PM CDT	Severe Thunderstorm Warning	FSD	McCook	46 min
Aug 20, 10:11 PM CDT	Severe Thunderstorm Warning	FSD	Hutchinson	49 min
Aug 21, 7:46 AM CDT	Flash Flood Warning	FSD	Minnehaha	119 min
Aug 21, 6:54 PM CDT	Severe Thunderstorm Warning	FSD	Gregory	51 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.