Alert archive / Iowa / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 52, NWS Sioux Falls, SD

April 30, 2001Woodbury County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Apr 30, 2001, 7:01 PM CDT for Woodbury County, Iowa. It was in force for 44 min. 3 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: Apr 30, 2001, 7:01 PM CDT (00:01 UTC)
Expired: Apr 30, 2001, 7:45 PM CDT
In force: 44 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), 112 km from the middle of the area, began a volume at 00:04 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
Apr 30, 7:04 PM CDT	Hail 0.75	Sergeant Bluff, IA
Apr 30, 7:30 PM CDT	Hail 0.75	Sergeant Bluff, IA
Apr 30, 7:55 PM CDT	Hail 2.5	Salix, IA	Large hail caused damage to vehicles and other property, but the amount of damage was not known.

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, 0.0 hours before the alert went out and 112 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: 1160 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 1364 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 142 m²/s²
0-3 km storm-relative helicity: 241 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 5.3

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KFSD 010003
SVRFSD

IAC193-010045-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
701 PM CDT MON APR 30 2001

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN WOODBURY COUNTY IN NORTHWEST IOWA

* UNTIL 745 PM CDT

* AT 701 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER SALIX...OR ABOUT 14 MILES SOUTH OF SIOUX
  CITY...MOVING EAST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  SLOAN AROUND 715 PM CDT
  HORNICK AROUND 735 PM CDT
  SMITHLAND AROUND 745 PM CDT

THIS STORM HAS A HISTORY OF PRODUCING LARGE HAIL. GO INSIDE A STURDY
BUILDING AND STAY AWAY FROM WINDOWS.

LAT...LON 4241 9639 4224 9646 4221 9584 4233 9583

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 30, 7:05 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	25 min
Apr 30, 7:19 PM CDT	Severe Thunderstorm Warning	FSD	Sioux	26 min
Apr 30, 7:24 PM CDT	Severe Thunderstorm Warning	FSD	Osceola	36 min
Apr 30, 7:28 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	32 min
Apr 30, 7:47 PM CDT	Severe Thunderstorm Warning	FSD	Woodbury	43 min
Apr 30, 7:59 PM CDT	Tornado Warning	FSD	Woodbury	31 min
May 1, 2:28 PM CDT	Severe Thunderstorm Warning	FSD	Woodbury	32 min
May 1, 2:58 PM CDT	Severe Thunderstorm Warning	FSD	Woodbury	47 min
May 1, 3:51 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	24 min
May 1, 4:08 PM CDT	Severe Thunderstorm Warning	FSD	Clay	22 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.