Alert archive / Iowa / Tornado Warnings in 2001

Tornado Warning 21, NWS Sioux Falls, SD

June 12, 2001Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jun 12, 2001, 6:35 PM CDT for Sioux County, Iowa. It was in force for 25 min. 3 reports came from 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, with what was reported inside it.

The facts

Issued: Jun 12, 2001, 6:35 PM CDT (23:35 UTC)
Expired: Jun 12, 2001, 7:00 PM CDT
In force: 25 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 62 km from the middle of the area, began a volume at 23:38 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
Jun 12, 6:45 PM CDT	Tornado F0	Rock Vly, IA	A brief tornado caused no reported damage or injuries.
Jun 12, 6:45 PM CDT	Hail 0.88	Rock Vly, IA
Jun 12, 7:09 PM CDT	Hail 0.88	Rock Vly, IA

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
Jun 12, 6:00 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.6 hours before the alert went out and 196 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: 2590 J/kg
Mixed-layer CIN: -222 J/kg
Mixed-layer LCL: 793 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 169 m²/s²
0-3 km storm-relative helicity: 194 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.6

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KFSD 122335
TORFSD
IAC167-130000-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
635 PM CDT TUE JUN 12 2001

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SIOUX COUNTY IN NORTHWEST IOWA

* UNTIL 700 PM CDT

* AT 635 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
  A DEVELOPING TORNADO NEAR HAWARDEN...MOVING NORTHEAST AT 20 MPH.

* THE TORNADO WILL BE NEAR...
  ROCK VALLEY AROUND 700 PM CDT

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

LAT...LON 4302 9653 4293 9642 4319 9617 4325 9636

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 11, 8:45 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, O'Brien	30 min
Jun 11, 8:48 PM CDT	Severe Thunderstorm Warning	FSD	Sioux	27 min
Jun 11, 9:07 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	38 min
Jun 11, 9:12 PM CDT	Severe Thunderstorm Warning	FSD	O'Brien	33 min
Jun 11, 9:44 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	31 min
Jun 11, 10:05 PM CDT	Severe Thunderstorm Warning	FSD	Clay, Dickinson	25 min
Jun 11, 10:13 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	17 min
Jun 11, 10:30 PM CDT	Severe Thunderstorm Warning	FSD	Clay	30 min
Jun 11, 10:39 PM CDT	Severe Thunderstorm Warning	FSD	O'Brien	21 min
Jun 11, 10:45 PM CDT	Severe Thunderstorm Warning	FSD	Clay	30 min
Jun 11, 11:15 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	30 min
Jun 12, 12:52 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	38 min
Jun 12, 2:17 PM CDT	Severe Thunderstorm Warning	FSD	O'Brien	28 min
Jun 12, 4:21 PM CDT	Severe Thunderstorm Warning	FSD	Osceola	24 min
Jun 12, 5:22 PM CDT	Severe Thunderstorm Warning	FSD	Sioux	23 min
Jun 12, 5:29 PM CDT	Severe Thunderstorm Warning	FSD	O'Brien, Osceola	31 min
Jun 12, 5:45 PM CDT	Severe Thunderstorm Warning	FSD	Dickinson	30 min
Jun 12, 5:51 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	39 min
Jun 12, 6:27 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	33 min
Jun 12, 6:58 PM CDT	Tornado Warning	FSD	Sioux	32 min

Nearby

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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.