Alert archive / Iowa / Tornado Warnings in 2014

Tornado Warning 6, NWS Sioux Falls, SD

May 11, 2014Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at May 11, 2014, 8:14 PM CDT for Sioux County, Iowa. It was in force for 31 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 11, 2014, 8:14 PM CDT (01:14 UTC)
Expired: May 11, 2014, 8:45 PM CDT
In force: 31 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.0 in

County Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 70 km from the middle of the area, began a volume at 01:14 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

Time	Report	Where	Remark
May 11, 8:23 PM CDT	HAIL 1.75	Sioux Center, IA
May 11, 8:35 PM CDT	TORNADO	7 Nne Orange City, IA
May 11, 8:37 PM CDT	TORNADO	4 W Hospers, IA
May 11, 8:42 PM CDT	TORNADO	5 Wnw Hospers, IA	SEVERE STRUCTURAL DAMAGE TO DAIRY FARM. 500 CATTLE LOOSE.
May 11, 8:43 PM CDT	TORNADO	4 Wnw Hospers, IA	SIGNIFICANT DAMAGE TO OUTBUILDING. ALSO SOME DAMAGE TO HOME INCLUDING BROKEN WINDOWS.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 1.2 hours before the alert went out and 201 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2520 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 967 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 274 m²/s²
0-3 km storm-relative helicity: 254 m²/s²
Significant tornado parameter: 4.5
Supercell composite: 18.8

Open this sounding in Storm Lab

The text

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

805 
WFUS53 KFSD 120114
TORFSD
IAC167-120145-
/O.NEW.KFSD.TO.W.0006.140512T0114Z-140512T0145Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
814 PM CDT SUN MAY 11 2014

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL SIOUX COUNTY IN NORTHWEST IOWA...

* UNTIL 845 PM CDT

* AT 809 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS LOCATED NEAR IRETON...AND MOVING NORTHEAST AT 35 MPH.

  HAZARD...TORNADO AND QUARTER SIZE HAIL.

  SOURCE...RADAR INDICATED ROTATION.

  IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT
           SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED. DAMAGE
           TO ROOFS...WINDOWS AND VEHICLES WILL OCCUR. TREE DAMAGE IS
           LIKELY.

* THIS DANGEROUS STORM WILL BE NEAR...
  SIOUX CENTER AROUND 820 PM CDT.
  HULL AROUND 830 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORNADOES ARE DIFFICULT TO SEE AND CONFIRM AT NIGHT. TAKE COVER NOW.

THIS LINE OF THUNDERSTORMS IS CAPABLE OF PRODUCING TORNADOES. DO NOT 
WAIT TO SEE OR HEAR THE TORNADO. FOR YOUR PROTECTION MOVE TO AN 
INTERIOR ROOM ON THE LOWEST FLOOR OF A BUILDING.

&&

LAT...LON 4325 9606 4305 9593 4296 9632 4307 9637
TIME...MOT...LOC 0113Z 247DEG 30KT 4306 9628

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

CHAPMAN

3 follow-up statements

288 
WWUS53 KFSD 120128
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
828 PM CDT SUN MAY 11 2014

IAC167-120145-
/O.CON.KFSD.TO.W.0006.000000T0000Z-140512T0145Z/
SIOUX IA-
828 PM CDT SUN MAY 11 2014

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL SIOUX COUNTY UNTIL
845 PM CDT...

AT 828 PM CDT...A WEATHER SPOTTER REPORTED ROTATION IN THE CLOUDS TO 
THE WEST OF ORANGE CITY. IN ADDITION...NATIONAL WEATHER SERVICE 
METEOROLOGISTS WERE TRACKING A SEVERE THUNDERSTORM CAPABLE OF 
PRODUCING A TORNADO.  THIS DANGEROUS STORM WAS LOCATED NEAR ORANGE 
CITY...MOVING NORTHEAST AT 40 MPH. ANOTHER LOCATION WHICH WAS 
EXHIBITING ROTAION WAS 5 MILES SOUTHWEST OF HULL. MOVING NORTHEAST 
AT 40 MPH.

THIS TORNADO WILL AFFECT MAINLY RURAL AREAS OF CENTRAL SIOUX COUNTY
BETWEEN SIOUX CENTER AND ORANGE CITY...AND ALSO SOUTHWEST OF HULL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORNADOES ARE DIFFICULT TO SEE AT NIGHT. TAKE COVER NOW.

&&

LAT...LON 4325 9606 4305 9593 4296 9632 4307 9637
TIME...MOT...LOC 0128Z 244DEG 36KT 4304 9607

$$

CHAPMAN

245 
WWUS53 KFSD 120136
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
836 PM CDT SUN MAY 11 2014

IAC167-120145-
/O.CON.KFSD.TO.W.0006.000000T0000Z-140512T0145Z/
SIOUX IA-
836 PM CDT SUN MAY 11 2014

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL SIOUX COUNTY UNTIL
845 PM CDT...

AT 835 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED JUST NORTH NORTHEAST OF ORANGE CITY...MOVING 
NORTHEAST AT 35 MPH.  THE ROTATION EARLIER NEAR HULL HAS DISSIPATED.

THIS TORNADO WILL AFFECT MAINLY RURAL AREAS OF CENTRAL SIOUX COUNTY
FROM NORTHEAST OF SIOUX CENTER TO WEST OF HOSPERS.

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 9609 4313 9615 4325 9606 4305 9593
TIME...MOT...LOC 0135Z 245DEG 30KT 4306 9600

$$

CHAPMAN

959 
WWUS53 KFSD 120147
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
847 PM CDT SUN MAY 11 2014

IAC167-120156-
/O.EXP.KFSD.TO.W.0006.000000T0000Z-140512T0145Z/
SIOUX IA-
847 PM CDT SUN MAY 11 2014

...THE TORNADO WARNING FOR CENTRAL SIOUX COUNTY HAS EXPIRED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED 
AREA. A TORNADO WARNING REMAINS IN EFFECT FOR EAST CENTRAL SIOUX
COUNTY AND WEST CENTRAL O'BRIEN COUNTY UNTIL 915 PM CDT. THE SEVERE 
STORM CAPABLE OF PRODUCING A TORNADO WAS LOCATED NEAR HOSPERS.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN SIOUX FALLS.

LAT...LON 4301 9609 4313 9615 4325 9606 4305 9593
TIME...MOT...LOC 0136Z 245DEG 30KT 4306 9599

$$

CHAPMAN

The office that day

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

Issued	Product	Office	Counties	Lasted
May 11, 7:55 PM CDT	Severe Thunderstorm Warning	FSD	Sioux	35 min
May 11, 8:42 PM CDT	Tornado Warning	FSD	O'Brien, Sioux	33 min
May 11, 9:10 PM CDT	Tornado Warning Tornado observed	FSD	O'Brien, Sioux	35 min

Nearby

Tornado Warnings in Iowa, 2014 Every tornado warning in 2014 Tornadoes in 2014

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.