Alert archive / Iowa / Tornado Warnings in 2000

Tornado Warning 10, NWS Sioux Falls, SD

July 9, 2000Lyon County, Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jul 9, 2000, 9:11 PM CDT for Lyon County, Sioux County, Iowa. It was in force for 34 min. 2 reports 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 9, 2000, 9:11 PM CDT (02:11 UTC)
Expired
Jul 9, 2000, 9:45 PM CDT
In force
34 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Lyon County, IA, Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 59 km from the middle of the area, began a volume at 02:12 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

TimeReportWhereRemark
Jul 9, 9:15 PM CDTTornado F1Doon, IAA tornado destroyed a machine shed and a garage. The tornado also uprooted several trees and flattened part of a corn crop. The tornado formed 5 miles east of Doon, then moved south, crossing the county line into Sioux County, where further damage occurred.
Jul 9, 9:17 PM CDTTornado F0Hull, IAA tornado crossed into Sioux County from Lyon County to the north, where it had caused damage. In Sioux County, the tornado blew down power lines and caused tree damage.

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

Omaha, NE (KOAX), launched 00:00Z, 2.2 hours before the alert went out and 213 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-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2000-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2654 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2000-07-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 111 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2654 J/kg
Mixed-layer CIN
-86 J/kg
Mixed-layer LCL
1802 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
111 m²/s²
0-3 km storm-relative helicity
252 m²/s²
Significant tornado parameter
0.3
Supercell composite
17.7

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KFSD 100212
TORFSD

IAC119-167-100245-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
911 PM CDT SUN JUL 9 2000

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHEAST LYON COUNTY IN NORTHWEST IOWA
  NORTHEAST SIOUX COUNTY IN NORTHWEST IOWA

* UNTIL 945 PM CDT

* AT 911 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  TORNADO 6 MILES NORTHWEST OF BOYDEN...OR ABOUT 13 MILES SOUTH OF
  ROCK RAPIDS...MOVING EAST AT 30 MPH.

* THE TORNADO WILL BE NEAR...
  MATLOCK AROUND 925 PM CDT

THIS IS AN EXTREMELY DANGEROUS AND POTENTIALLY LIFE THREATENING
SITUATION. IF YOU ARE IN THE PATH OF THISF TORNADO...TAKE COVER
IMMEDIATELY. GO TO THE BASEMENT. IF A BASEMENT IS NOT AVAILABLE...GO
TO A SMALL INTERIOR ROOM ON THE LOWEST FLOOR.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 9:39 PM CDTTornado WarningFSDO'Brien, Osceola36 min
Jul 9, 10:14 PM CDTTornado WarningFSDO'Brien, Osceola31 min
Jul 9, 10:18 PM CDTFlash Flood WarningFSDDickinson87 min
Jul 9, 10:24 PM CDTSevere Thunderstorm WarningFSDClay, Dickinson36 min
Jul 9, 10:39 PM CDTFlash Flood WarningFSDClay, O'Brien96 min

Nearby

Tornado Warnings in Iowa, 2000Every tornado warning in 2000Tornadoes in 2000

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.