Alert archive / Iowa / Tornado Warnings in 1998

Tornado Warning 51, NWS Sioux Falls, SD

August 24, 1998Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Aug 24, 1998, 9:22 AM CDT for Sioux County, Iowa. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 24, 1998, 9:22 AM CDT (14:22 UTC)
Expired
Aug 24, 1998, 10:10 AM CDT
In force
48 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 72 km from the middle of the area, began a volume at 14:25 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 24, 7:45 AM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 2.4 hours before the alert went out and 197 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 1998-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 377 joules per kilogram.LCLLFCEL10008507005003002001001 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 1998-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -145 square meters per square second.19395878Sfc1 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
377 J/kg
Mixed-layer CIN
-480 J/kg
Mixed-layer LCL
2119 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
-145 m²/s²
0-3 km storm-relative helicity
-145 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.

679 
WFUS1 KFSD 241423 RRA
TORFSD
IAC167-241510-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
922 AM CDT MON AUG 24 1998

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SIOUX COUNTY IN NORTHWESTERN IOWA

* UNTIL 1010 AM CDT

* AT 920 AM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A DEVELOPING TORNADO 21 MILES SOUTH OF SIOUX FALLS OR NEAR
  FAIRVIEW MOVING EAST AT 45 MPH.

* THE TORNADO IS EXPECTED TO BE NEAR...
  ROCK VALLEY              AROUND 935 AM CDT
  CARMEL                   AROUND 940 AM CDT
  PERKINS                  AROUND 940 AM CDT
  HULL                     AROUND 945 AM CDT
  BOYDEN                   AROUND 955 AM CDT

THIS REPLACES THE SEVERE THUNDERSTORM WARNING FOR SIOUX COUNTY.

IF YOU ARE CAUGHT OUTSIDE...SEEK SAFETY IN A NEARBY STURDY
BUILDING. AS A LAST RESORT... SEEK REFUGE IN A CULVERT...
DITCH OR LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS. BEWARE
THE THREAT OF RISING WATER.

FUHS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 8:01 AM CDTSevere Thunderstorm WarningFSDClay, Dickinson34 min
Aug 24, 9:19 AM CDTSevere Thunderstorm WarningFSDLyon, Sioux61 min

Nearby

Tornado Warnings in Iowa, 1998Every tornado warning in 1998Tornadoes in 1998

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.