Alert archive / South Dakota / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 281, NWS Sioux Falls, SD

July 21, 2001Charles Mix County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 21, 2001, 11:50 PM CDT for Charles Mix County, South Dakota. It was in force for 25 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 21, 2001, 11:50 PM CDT (04:50 UTC)
Expired: Jul 22, 2001, 12:15 AM CDT
In force: 25 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties

County Charles Mix County, SD

The radar

The Sioux Falls radar (KFSD), 156 km from the middle of the area, began a volume at 04:50 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
Jul 22, 12:00 AM CDT	Thunderstorm Wind 61 E	Dante, SD	Thunderstorm winds destroyed part of a large cattle shed. There was no livestock in the building at the time.

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 nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 4.8 hours before the alert went out and 189 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: 3348 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 1072 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 146 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 5.4

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KFSD 220450 CCA
SVRFSD

SDC023-220515-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1150 PM CDT SAT JUL 21 2001

CORRECTED TO SPECIFY NORTHERN CHARLES MIX COUNTY

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN CHARLES MIX COUNTY IN SOUTH CENTRAL SOUTH DAKOTA

* UNTIL 1215 AM CDT

* AT 1148 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 9 MILES WEST OF PLATTE...OR ABOUT 30 MILES
  NORTHWEST OF LAKE ANDES...MOVING EAST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  PLATTE AROUND 1205 AM CDT

LAT...LON 4347 991H9 4330 9904 4332 9871 4348 9879

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.

NWS Sioux Falls, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 21, 9:15 PM CDT, 2 hours 35 minutes earlier.

Area forecast discussion, Jul 21, 9:15 PM CDT, 2 hours 35 minutes before

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
915 PM CDT SAT JUL 21 2001

UPDATED THE CWA ZONE AT 02Z. TOOK THE OPPORTUNITY TO CANCEL PART OF
SEVERE THUNDERSTORM WATCH 610 FOR THE COUNTIES ALONG AND SOUTH OF
INTERSTATE 90...WHILE LEAVING EAST CENTRAL SOUTH DAKOTA COUNTIES
NORTH OF I90 IN THE WATCH AND MOST ALL OF THE SOUTHWEST MINNESOTA
COUNTIES EXCEPT ROCK. DOUBTFUL THAT ANY SEVERE WEATHER IS GOING TO
DEVELOP IN THE SOUTHERN PART OF THE WATCH PRIOR TO 11 PM.  WARM
ADVECTION AND AN INCREASE IN THE LOW LEVEL JET ALONG WITH LEFT OVER
BOUNDARIES COULD STILL LEAD TO THUNDERSTORM DEVELOPMENT IN THE NORTH
PART OF THE CWA. ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT IS
STILL POSSIBLE DURING THE NIGHTTIME HOURS...BUT LOWERED THE POPS A
BIT IN THE FORECAST AREA. CLEANED UP THE WIND FORECAST AND LEFT THE
MIN TEMPERATURES AS ISSUED EARLIER.

.FSD...NONE
  UMLAND

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 11:15 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix	30 min
Jul 22, 1:31 AM CDT	Severe Thunderstorm Warning	FSD	Bon Homme, Hutchinson, Yankton	29 min
Jul 22, 1:38 AM CDT	Severe Thunderstorm Warning	FSD	Hanson	37 min
Jul 22, 2:08 AM CDT	Severe Thunderstorm Warning	FSD	Yankton	37 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2001 Every severe thunderstorm warning in 2001

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.