Alert archive / Iowa / Tornado Warnings in 1998

Tornado Warning 10, NWS Sioux Falls, SD

May 15, 1998Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at May 15, 1998, 4:24 PM CDT for Sioux County, Iowa. It was in force for 31 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
May 15, 1998, 4:24 PM CDT (21:24 UTC)
Expired
May 15, 1998, 4:55 PM CDT
In force
31 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 21:24 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
May 15, 3:00 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 9.4 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 1998-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1194 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 1998-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -76 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
1194 J/kg
Mixed-layer CIN
-370 J/kg
Mixed-layer LCL
1627 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
-76 m²/s²
0-3 km storm-relative helicity
26 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

780 
WFUS1 KFSD 152125 RRA
TORFSD
IAC167-152155-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
424 PM CDT FRI MAY 15 1998

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

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

* UNTIL 455 PM CDT

* AT 422 PM CDT... LOCAL LAW ENFORCEMENT OFFICIALS REPORTED A
  TORNADO JUST WEST OF SIOUX CENTER MOVING NORTHEAST AT 25 MPH.

* THE TORNADO IS EXPECTED TO BE NEAR...
  CARMEL                   AROUND 430 PM CDT
  PERKINS                  AROUND 435 PM CDT
  HULL                     AROUND 435 PM CDT



IF YOU ARE IN THE PATH OF A TORNADO...THE SAFEST PLACE IN A HOME OR
BUSINESS IS AN INTERIOR ROOM ON THE LOWEST FLOOR POSSIBLE.  AVOID
WINDOWS.

&

The office that day

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

IssuedProductOfficeCountiesLasted
May 15, 10:09 AM CDTSevere Thunderstorm WarningFSDIda, Woodbury51 min
May 15, 10:52 AM CDTSevere Thunderstorm WarningFSDCherokee, Plymouth28 min
May 15, 11:09 AM CDTSevere Thunderstorm WarningFSDBuena Vista31 min
May 15, 11:14 AM CDTSevere Thunderstorm WarningFSDO'Brien, Sioux31 min
May 15, 11:14 AM CDTSevere Thunderstorm WarningFSDClay31 min
May 15, 11:20 AM CDTSevere Thunderstorm WarningFSDPlymouth35 min
May 15, 4:09 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Cherokee31 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.