Alert archive / Iowa / Tornado Warnings in 2001

Tornado Warning 70, NWS Sioux Falls, SD

August 17, 2001Woodbury County, Iowa; Dakota County, Nebraska

NWS Sioux Falls, SD issued this tornado warning at Aug 17, 2001, 5:55 PM CDT for Woodbury County, Iowa; Dakota County, Nebraska. It was in force for 35 min. 4 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: Aug 17, 2001, 5:55 PM CDT (22:55 UTC)
Expired: Aug 17, 2001, 6:30 PM CDT
In force: 35 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties; the outline is the Mesonet’s reconstruction

Counties Woodbury County, IA, Dakota County, NE

The radar

The Sioux Falls radar (KFSD), 113 km from the middle of the area, began a volume at 22:56 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
Aug 17, 6:00 PM CDT	Tornado F0	Quimby, IA	A brief tornado caused no reported damage.
Aug 17, 6:18 PM CDT	Hail 0.88	Remsen, IA
Aug 17, 6:19 PM CDT	Hail 1.25	Remsen, IA
Aug 17, 6:20 PM CDT	Hail 1.75	Remsen, 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
Aug 17, 5:30 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.9 hours before the alert went out and 169 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: 1475 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: -21 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 172257
TORFSD
IAC035-149-172345-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
555 PM CDT FRI AUG 17 2001

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  WESTERN CHEROKEE COUNTY IN NORTHWEST IOWA
  EASTERN PLYMOUTH COUNTY IN NORTHWEST IOWA

* UNTIL 645 PM CDT

* AT 555 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  TORNADO 8 MILES NORTH OF REMSEN...OR ABOUT 6 MILES SOUTHEAST OF
  ORANGE CITY...MOVING SOUTHEAST AT 20 MPH.

* THE TORNADO WILL BE NEAR...
  REMSEN AROUND 610 PM CDT
  MARCUS AROUND 620 PM CDT

THIS TORNADO WARNING EXTENDS THE PREVIOUS TORNADO WARNINGS.

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

LAT...LON 4291 9588 4290 9612 4257 9588 4267 9558

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 4:07 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	23 min
Aug 17, 4:27 PM CDT	Severe Thunderstorm Warning	FSD	Lyon, Sioux	33 min
Aug 17, 4:57 PM CDT	Severe Thunderstorm Warning	FSD	Sioux	33 min
Aug 17, 5:04 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth	26 min
Aug 17, 5:15 PM CDT	Tornado Warning	FSD	Sioux	30 min
Aug 17, 5:22 PM CDT	Severe Thunderstorm Warning	FSD	Woodbury	23 min
Aug 17, 5:28 PM CDT	Tornado Warning	FSD	Woodbury	32 min
Aug 17, 5:30 PM CDT	Tornado Warning	FSD	Plymouth	30 min
Aug 17, 5:37 PM CDT	Tornado Warning	FSD	Cherokee	23 min
Aug 17, 5:43 PM CDT	Tornado Warning	FSD	Sioux	32 min
Aug 17, 5:55 PM CDT	Tornado Warning	FSD	Cherokee, Plymouth	50 min
Aug 17, 6:30 PM CDT	Tornado Warning	FSD	Woodbury	15 min
Aug 17, 6:39 PM CDT	Tornado Warning	FSD	Ida, Woodbury	51 min
Aug 17, 6:44 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth	16 min

Nearby

Tornado Warnings in Iowa, 2001 Tornado Warnings in Nebraska, 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.