Alert archive / Iowa / Tornado Warnings in 2012

Tornado Warning 22, NWS Sioux Falls, SD

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

NWS Sioux Falls, SD issued this tornado warning at May 4, 2012, 3:43 PM CDT for O'Brien County, Sioux County, Iowa. It was in force for 32 min. 3 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, 3:43 PM CDT (20:43 UTC)
Expired
May 4, 2012, 4:15 PM CDT
In force
32 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), 100 km from the middle of the area, began a volume at 20:43 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, 3:45 PM CDTTSTM WND GST 60Sheldon, IA
May 4, 3:50 PM CDTTORNADO3 W Primghar, IA
May 4, 4:15 PM CDTTSTM WND GST 604 Ene Hartley, IASMALL BRANCHES DOWN.

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, 8.7 hours before the alert went out and 208 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.

651 
WFUS53 KFSD 042043
TORFSD
IAC141-167-042115-
/O.NEW.KFSD.TO.W.0022.120504T2043Z-120504T2115Z/

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

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  O'BRIEN COUNTY IN NORTHWEST IOWA...
  NORTHEASTERN SIOUX COUNTY IN NORTHWEST IOWA...

* UNTIL 415 PM CDT

* AT 342 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
  DANGEROUS STORM WAS LOCATED NEAR ARCHER...OR 14 MILES EAST OF
  ORANGE CITY...AND MOVING EAST AT 40 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
  PRIMGHAR AND SANBORN AROUND 350 PM CDT...
  HARTLEY AROUND 405 PM CDT...

IN ADDITION TO THE THREAT FOR A TORNADO...HAIL TO THE SIZE OF GOLF 
BALLS AND WIND GUSTS TO 70 MPH.

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 4297 9586 4326 9593 4326 9563 4325 9539
      4302 9540
TIME...MOT...LOC 2042Z 252DEG 35KT 4309 9576

$$

SCHUMACHER
3 follow-up statements
271 
WWUS53 KFSD 042052
SVSFSD

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

IAC167-042101-
/O.CAN.KFSD.TO.W.0022.000000T0000Z-120504T2115Z/
SIOUX IA-
352 PM CDT FRI MAY 4 2012

...THE TORNADO WARNING FOR NORTHEASTERN SIOUX COUNTY IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED 
AREA.

LAT...LON 4298 9580 4324 9582 4326 9563 4325 9539
      4302 9540
TIME...MOT...LOC 2051Z 256DEG 42KT 4310 9563

$$

IAC141-042115-
/O.CON.KFSD.TO.W.0022.000000T0000Z-120504T2115Z/
O'BRIEN IA-
352 PM CDT FRI MAY 4 2012

...A TORNADO WARNING REMAINS IN EFFECT FOR O'BRIEN COUNTY UNTIL 415
PM CDT...

AT 351 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A CONFIRMED TORNADO.  THIS DANGEROUS STORM WAS LOCATED 3 MILES WEST 
OF PRIMGHAR...OR 20 MILES EAST OF ORANGE CITY...MOVING EAST AT 50 MPH.

THIS DANGEROUS STORM WILL BE NEAR...
  PRIMGHAR THROUGH 355 PM CDT.
  HARTLEY AROUND 405 PM CDT...

AT 350 PM CDT...A TRAINED SPOTTER REPORTED A TORNADO 3 MILES WEST OF 
PRIMGHAR.

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 4298 9580 4324 9582 4326 9563 4325 9539
      4302 9540
TIME...MOT...LOC 2051Z 256DEG 42KT 4310 9563

$$

SCHUMACHER
349 
WWUS53 KFSD 042059
SVSFSD

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

IAC141-042115-
/O.CON.KFSD.TO.W.0022.000000T0000Z-120504T2115Z/
O'BRIEN IA-
359 PM CDT FRI MAY 4 2012

...A TORNADO WARNING REMAINS IN EFFECT FOR O'BRIEN COUNTY UNTIL 415
PM CDT...

AT 357 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
TWO SEVERE THUNDERSTORMS WITH A CAPABLE OF PRODUCING A TORNADO. ONE 
DANGEROUS STORM WAS LOCATED ALONG 2 MILES NORTH OF SANBORN...THE 
SECOND DANGEROUS STORM WAS LOCATED NEAR PRIMGHAR. BOTH STORMS ARE 
MOVING EAST AT 35 MPH.

THESE DANGEROUS STORMS WILL BE NEAR...
  HARTLEY AROUND 405 PM CDT...

IN ADDITION TO THE THREAT FOR TORNADOES...THESE STORMS ARE CAPABLE 
OF PRODUCING GOLF BALL SIZE HAIL AND WINDS TO 70 MPH.

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 4298 9580 4324 9582 4326 9563 4325 9539
      4302 9540
TIME...MOT...LOC 2057Z 264DEG 28KT 4322 9554 4310 9559

$$

SCHUMACHER
382 
WWUS53 KFSD 042114
SVSFSD

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

IAC141-042124-
/O.EXP.KFSD.TO.W.0022.000000T0000Z-120504T2115Z/
O'BRIEN IA-
414 PM CDT FRI MAY 4 2012

...THE TORNADO WARNING FOR O'BRIEN COUNTY WILL EXPIRE AT 415 PM
CDT...

THE TORNADO THREAT HAS DIMINISHED...THEREFORE THE TORNADO WARNING HAS
EXPIRED. HOWEVER...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT 
FOR THE AREA FOR WINDS GUSTING UP TO 60 MPH.

LAT...LON 4298 9580 4324 9582 4326 9563 4325 9539
      4302 9540
TIME...MOT...LOC 2114Z 264DEG 28KT 4323 9536 4311 9541

$$

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, 3:20 PM CDTTornado WarningFSDO'Brien, Sioux25 min
May 4, 3:39 PM CDTSevere Thunderstorm WarningFSDPlymouth36 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.