Alert archive / Iowa / Tornado Warnings in 2012

Tornado Warning 21, NWS Sioux Falls, SD

May 4, 2012O'Brien County, Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at May 4, 2012, 3:20 PM CDT for O'Brien County, Sioux County, Iowa. It was in force for 25 min. 5 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 4, 2012, 3:20 PM CDT (20:20 UTC)
Expired
May 4, 2012, 3:45 PM CDT
In force
25 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

Counties O'Brien County, IA, Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 83 km from the middle of the area, began a volume at 20:20 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
May 4, 3:22 PM CDTTORNADO3 N Orange City, IA
May 4, 3:40 PM CDTTSTM WND DMG3 E Hospers, IASMALL BRANCHES BROKEN.
May 4, 3:40 PM CDTNON-TSTM WND DMG3 E Hospers, IASMALL BRANCHES BROKEN.
May 4, 3:45 PM CDTTSTM WND GST 60Sheldon, IA
May 4, 3:46 PM CDTTSTM WND GST 70N Hospers, IAPEA SIZE HAIL WAS ALSO PRESENT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
May 4, 2:00 PM CDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 8.3 hours before the alert went out and 206 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 2012-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2705 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2012-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 square meters per square second.1939Sfc1 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
2705 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
584 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
98 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.

123 
WFUS53 KFSD 042020
TORFSD
IAC141-167-042045-
/O.NEW.KFSD.TO.W.0021.120504T2020Z-120504T2045Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
320 PM CDT FRI MAY 4 2012

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWESTERN O'BRIEN COUNTY IN NORTHWEST IOWA...
  EAST CENTRAL SIOUX COUNTY IN NORTHWEST IOWA...

* UNTIL 345 PM CDT

* AT 320 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
  DANGEROUS STORM WAS LOCATED NEAR SIOUX CENTER...OR 7 MILES NORTH OF
  ORANGE CITY...AND MOVING EAST AT 35 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
  HOSPERS AROUND 330 PM CDT...
  SHELDON AROUND 340 PM CDT...
  ARCHER AROUND 345 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4325 9575 4307 9572 4300 9614 4314 9620
TIME...MOT...LOC 2020Z 254DEG 32KT 4311 9605

$$

SCHUMACHER
1 follow-up statement
257 
WWUS53 KFSD 042028
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
328 PM CDT FRI MAY 4 2012

IAC141-167-042045-
/O.CON.KFSD.TO.W.0021.000000T0000Z-120504T2045Z/
SIOUX IA-O'BRIEN IA-
328 PM CDT FRI MAY 4 2012

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHWESTERN O'BRIEN AND
EAST CENTRAL SIOUX COUNTIES UNTIL 345 PM CDT...

AT 328 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR HOSPERS...OR 6 MILES NORTHEAST OF ORANGE
CITY...MOVING EAST AT 40 MPH.

THIS DANGEROUS STORM WILL BE NEAR...
  ARCHER AROUND 345 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4301 9608 4313 9613 4325 9575 4307 9572
TIME...MOT...LOC 2028Z 257DEG 34KT 4308 9595

$$

SCHUMACHER

The office that day

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

IssuedProductOfficeCountiesLasted
May 3, 7:57 PM CDTSevere Thunderstorm WarningFSDCherokee33 min
May 3, 8:05 PM CDTFlash Flood WarningFSDCherokee93 min
May 3, 8:37 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Cherokee38 min
May 4, 3:00 PM CDTSevere Thunderstorm WarningFSDSioux30 min
May 4, 3:14 PM CDTSevere Thunderstorm WarningFSDPlymouth, Sioux31 min
May 4, 3:18 PM CDTSevere Thunderstorm WarningFSDO'Brien, Osceola, Sioux42 min
May 4, 3:39 PM CDTSevere Thunderstorm WarningFSDPlymouth36 min
May 4, 3:43 PM CDTTornado WarningFSDO'Brien, Sioux32 min
May 4, 4:01 PM CDTSevere Thunderstorm WarningFSDCherokee, O'Brien29 min
May 4, 4:06 PM CDTTornado WarningFSDClay24 min
May 4, 4:09 PM CDTSevere Thunderstorm WarningFSDDickinson, Osceola51 min
May 4, 4:12 PM CDTSevere Thunderstorm WarningFSDClay, O'Brien33 min
May 4, 4:25 PM CDTSevere Thunderstorm WarningFSDClay35 min

Nearby

Tornado Warnings in Iowa, 2012Every tornado warning in 2012Tornadoes in 2012

Sources

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