Alert archive / Iowa / Tornado Warnings in 2001

Tornado Warning 58, NWS Sioux Falls, SD

June 18, 2001Woodbury County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jun 18, 2001, 7:09 PM CDT for Woodbury County, Iowa. It was in force for 36 min. 2 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 18, 2001, 7:09 PM CDT (00:09 UTC)
Expired: Jun 18, 2001, 7:45 PM CDT
In force: 36 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Woodbury County, IA

The radar

The Omaha radar (KOAX), 111 km from the middle of the area, began a volume at 00:12 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 18, 7:12 PM CDT	Hail 1	Hornick, IA
Jun 18, 7:19 PM CDT	Hail 0.88	Oto, 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 18, 6:00 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.2 hours before the alert went out and 111 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: 2637 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 2202 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 346 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 16.5

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KFSD 190011
TORFSD

IAC193-190045-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
709 PM CDT MON JUN 18 2001

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHERN WOODBURY COUNTY IN NORTHWEST IOWA

* UNTIL 745 PM CDT

* AT 709 PM CDT...WEATHER SPOTTERS REPORTED A TORNADO 3 MILES EAST
  OF HORNICK...OR ABOUT 27 MILES SOUTHEAST OF SIOUX CITY...MOVING
  NORTHEAST AT 40 MPH.

* THE TORNADO WILL BE NEAR...
  SMITHLAND AROUND 715 PM CDT
  DANBURY AROUND 725 PM CDT

THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. TAKE
COVER NOW.

LAT...LON 4226 9623 4222 9622 4222 9568 4246 9568

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 18, 7:15 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Cherokee, Clay	45 min
Jun 18, 7:15 PM CDT	Severe Thunderstorm Warning	FSD	Ida, Woodbury	45 min
Jun 18, 8:00 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	15 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.