Alert archive / South Dakota / Tornado Warnings in 2001

Tornado Warning 3, NWS Sioux Falls, SD

April 11, 2001Union County, South Dakota; Dakota County, Nebraska; Woodbury County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Apr 11, 2001, 2:28 PM CDT for Union County, South Dakota; Dakota County, Nebraska; Woodbury County, Iowa. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Apr 11, 2001, 2:28 PM CDT (19:28 UTC)
Expired: Apr 11, 2001, 3:00 PM CDT
In force: 32 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties; the outline is the Mesonet’s reconstruction

Counties Woodbury County, IA, Dakota County, NE, Union County, SD

The radar

The Sioux Falls radar (KFSD), 120 km from the middle of the area, began a volume at 19:29 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.

The watch it was issued in

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

Issued	Product	Office	Lasted
Apr 11, 10:45 AM CDT	Tornado Watch	SPC	5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 7.5 hours before the alert went out and 134 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1274 m above ground
0-6 km bulk shear: 77 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 163 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.

000 
WFUS53 KFSD 111929
TORFSD
IAC193-NEC043-SDC127-112000-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
228 PM CDT WED APR 11 2001

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHERN DAKOTA COUNTY IN NORTHEAST NEBRASKA
  NORTHWEST WOODBURY COUNTY IN NORTHWEST IOWA
  SOUTHERN UNION COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 300 PM CDT

* AT 228 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  TORNADO 4 MILES WEST OF DAKOTA CITY...OR ABOUT 7 MILES SOUTHWEST OF
  SIOUX CITY...MOVING NORTH AT 40 MPH.

* THE TORNADO WILL BE NEAR...
  NORTH SIOUX CITY AROUND 235 PM CDT
  JEFFERSON AROUND 240 PM CdDT
  ELK POINT AROUND 250 PM CDT

IF YOU ARE IN THE PATH OF THIS TORNADO...TAKE COVER IMMEDIATELY.

LAT...LON 4234 9658 4244 9635 4270 9659 4274 9672

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 11, 11:23 AM CDT	Severe Thunderstorm Warning	FSD	Clay	37 min
Apr 11, 1:56 PM CDT	Tornado Warning	FSD	Dakota	34 min
Apr 11, 12:38 AM CDT	Severe Thunderstorm Warning	FSD	Woodbury	37 min
Apr 11, 2:37 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Ida	23 min
Apr 11, 2:58 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee	32 min

Nearby

Tornado Warnings in South Dakota, 2001 Tornado Warnings in Nebraska, 2001 Tornado Warnings in Iowa, 2001 Every tornado warning in 2001 Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.