Alert archive / Iowa / Tornado Warnings in 2000

Tornado Warning 11, NWS Sioux Falls, SD

July 9, 2000O'Brien County, Osceola County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jul 9, 2000, 9:39 PM CDT for O'Brien County, Osceola County, Iowa. It was in force for 36 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, 9:39 PM CDT (02:39 UTC)
Expired: Jul 9, 2000, 10:15 PM CDT
In force: 36 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties

Counties O'Brien County, IA, Osceola County, IA

The radar

The Sioux Falls radar (KFSD), 98 km from the middle of the area, began a volume at 02:42 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 9, 9:51 PM CDT	Thunderstorm Wind 52 E	Sheldon, IA	Thunderstorm winds caused tree damage, including some trees blown down.
Jul 9, 10:10 PM CDT	Thunderstorm Wind 52 E	Melvin, 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 nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.7 hours before the alert went out and 221 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: 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 100241
TORFSD

IAC141-143-100315-

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

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWEST O'BRIEN COUNTY IN NORTHWEST IOWA
  SOUTHWEST OSCEOLA COUNTY IN NORTHWEST IOWA

* UNTIL 1015 PM CDT

* AT 939 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
  TORNADO 7 MILES SOUTHWEST OF ASHTON...OR ABOUT 18 MILES SOUTHEAST  
  OF ROCK RAPIDS...MOVING EAST AT 25 MPH. AT 915 PM CDT A TORNADO
  AND PWER LINE DAMAGE WAS OBSERVED 3 AND A HALF MILES NORTH OF HULL 
  IOWA.

* THE TORNADO WILL BE NEAR...
  ASHTON AROUND 1000 PM CDT

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

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 9:11 PM CDT	Tornado Warning	FSD	Lyon, Sioux	34 min
Jul 9, 10:14 PM CDT	Tornado Warning	FSD	O'Brien, Osceola	31 min
Jul 9, 10:18 PM CDT	Flash Flood Warning	FSD	Dickinson	87 min
Jul 9, 10:24 PM CDT	Severe Thunderstorm Warning	FSD	Clay, Dickinson	36 min
Jul 9, 10:39 PM CDT	Flash Flood Warning	FSD	Clay, O'Brien	96 min

Nearby

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