Alert archive / Iowa / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 49, NWS Sioux Falls, SD

April 30, 2001Woodbury County, Iowa; Dakota County, Nebraska

NWS Sioux Falls, SD issued this severe thunderstorm warning at Apr 30, 2001, 6:29 PM CDT for Woodbury County, Iowa; Dakota County, Nebraska. It was in force for 31 min. 5 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, 6:29 PM CDT (23:29 UTC)
Expired
Apr 30, 2001, 7:00 PM CDT
In force
31 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 Omaha radar (KOAX), 119 km from the middle of the area, began a volume at 23:29 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
Apr 30, 6:38 PM CDTHail 0.75Dakota City, NE
Apr 30, 6:46 PM CDTHail 1Homer, NE
Apr 30, 6:55 PM CDTHail 1Homer, NE
Apr 30, 6:59 PM CDTHail 1.75Homer, NE
Apr 30, 7:04 PM CDTHail 0.75Sergeant Bluff, 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, 11.5 hours before the alert went out and 119 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 12:00Z on 2001-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2001-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 255 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1416 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
255 m²/s²
0-3 km storm-relative helicity
246 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 
WUUS53 KFSD 302329
SVRFSD
IAC193-NEC043-010000-

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

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN DAKOTA COUNTY IN NORTHEAST NEBRASKA
  WESTERN WOODBURY COUNTY IN NORTHWEST IOWA

* UNTIL 700 PM CDT

* AT 629 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 4 MILES EAST OF HUBBARD...OR ABOUT 10 MILES
  SOUTHWEST OF SIOUX CITY...MOVING EAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HOMER AROUND 635 PM CDT
  DAKOTA CITY AROUND 640 PM CDT
  SERGEANT BLUFF AROUND 650 PM CDT
  SALIX AROUND 655 PM CDT

A TRAINED WEATHER SPOTTER REPORTED ONE INCH HAIL AT 615 PM CDT ONE
MILE SOUTHEAST OF HUBBARD.

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

LAT...LON 4249 9660 4231 9666 4224 9620 4242 9613

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 30, 5:16 PM CDTSevere Thunderstorm WarningFSDO'Brien, Plymouth, Sioux44 min
Apr 30, 5:21 PM CDTSevere Thunderstorm WarningFSDWoodbury24 min
Apr 30, 5:35 PM CDTTornado WarningFSDO'Brien25 min
Apr 30, 6:01 PM CDTTornado WarningFSDO'Brien, Sioux29 min
Apr 30, 6:04 PM CDTSevere Thunderstorm WarningFSDWoodbury26 min
Apr 30, 6:46 PM CDTSevere Thunderstorm WarningFSDSioux29 min
Apr 30, 5:32 PM CDTSevere Thunderstorm WarningFSDDakota, Dixon28 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2001Severe Thunderstorm Warnings in Nebraska, 2001Every 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.