Alert archive / Iowa / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 308, NWS Sioux Falls, SD

August 17, 2001Sioux County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 17, 2001, 4:57 PM CDT for Sioux County, Iowa. It was in force for 33 min. 1 report 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, 4:57 PM CDT (21:57 UTC)
Expired: Aug 17, 2001, 5:30 PM CDT
In force: 33 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), 67 km from the middle of the area, began a volume at 21:57 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, 5:05 PM CDT	Hail 0.75	Sioux Center, 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 12:00Z, 10.0 hours before the alert went out and 209 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.

244 
WUUS53 KFSD 172158
SVRFSD
IAC167-172230-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
457 PM CDT FRI AUG 17 2001

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SIOUX COUNTY IN NORTHWEST IOWA

* UNTIL 530 PM CDT

* AT 457 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER HULL...OR ABOUT 14 MILES NORTH OF ORANGE
  CITY...MOVING SOUTHEAST AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  BOYDEN AROUND 515 PM CDT
  SIOUX CENTER AROUND 520 PM CDT

AT 440 PM CDT QUARTER SIZE HAIL WAS REPORTED AT DOON.

THIS STORM WILL PRODUCE LARGE HAIL. GO INSIDE A STURDY BUILDING AND
STAY AWAY FROM WINDOWS.

LAT...LON 4326 9612 4317 9627 4304 9615 4322 9590

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, 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, 5:55 PM CDT	Tornado Warning	FSD	Woodbury	35 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

Severe Thunderstorm Warnings in Iowa, 2001 Every severe thunderstorm warning 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.