Alert archive / Iowa / Tornado Warnings in 2014

Tornado Warning 8, NWS Sioux Falls, SD

May 11, 2014O'Brien County, Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at May 11, 2014, 9:10 PM CDT for O'Brien County, Sioux County, Iowa. It was in force for 35 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 11, 2014, 9:10 PM CDT (02:10 UTC)
Expired: May 11, 2014, 9:45 PM CDT
In force: 35 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Tornado: Observed
Hail: 0.0 in

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

The radar

The Sioux Falls radar (KFSD), 86 km from the middle of the area, began a volume at 02:10 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 nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.2 hours before the alert went out and 214 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.

210 
WFUS53 KFSD 120210
TORFSD
IAC141-167-120245-
/O.NEW.KFSD.TO.W.0008.140512T0210Z-140512T0245Z/

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

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

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

* UNTIL 945 PM CDT

* AT 905 PM CDT...A CONFIRMED TORNADO WAS LOCATED NEAR SHELDON...AND
  MOVING NORTHEAST AT 15 MPH.

  HAZARD...DAMAGING TORNADO.

  SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO.

  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.

* LOCATIONS IMPACTED INCLUDE...
  MAINLY RURAL AREAS OF NORTHWESTERN O'BRIEN COUNTY.

AT 858 PM CDT...A TORNADO WAS REPORTED BY WEATHER SPOTTER 3 MILES 
SOUTHWEST OF SHELDON.  A NEW CIRCULATION WAS DEVELOPING RAPIDLY JUST 
EAST OF SHELDON...MOVING NORTHEAST AT 20 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING TORNADOES. TAKE COVER IN A
BASEMENT OR STORM SHELTER NOW!

&&

LAT...LON 4312 9587 4318 9593 4326 9582 4326 9580
      4326 9569 4320 9563
TIME...MOT...LOC 0208Z 213DEG 12KT 4319 9581

TORNADO...OBSERVED
HAIL...0.00IN

$$

CHAPMAN

2 follow-up statements

443 
WWUS53 KFSD 120218
SVSFSD

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

IAC167-120227-
/O.CAN.KFSD.TO.W.0008.000000T0000Z-140512T0245Z/
SIOUX IA-
918 PM CDT SUN MAY 11 2014

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

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

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 4320 9563 4317 9573 4321 9583 4326 9582
      4326 9580 4326 9569
TIME...MOT...LOC 0217Z 215DEG 18KT 4323 9577

$$

IAC141-120245-
/O.CON.KFSD.TO.W.0008.000000T0000Z-140512T0245Z/
O'BRIEN IA-
918 PM CDT SUN MAY 11 2014

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTH CENTRAL O'BRIEN
COUNTY UNTIL 945 PM CDT...

AT 917 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM WITH A HISTORY OF OF PRODUCING A TORNADO.  THIS
DANGEROUS STORM WAS LOCATED 5 MILES NORTHEAST OF SHELDON...OR 20 
MILES NORTHEAST OF ORANGE CITY...MOVING NORTHEAST AT 20 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4320 9563 4317 9573 4321 9583 4326 9582
      4326 9580 4326 9569
TIME...MOT...LOC 0217Z 215DEG 18KT 4323 9577

$$

CHAPMAN

025 
WWUS53 KFSD 120225
SVSFSD

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

IAC141-120235-
/O.CAN.KFSD.TO.W.0008.000000T0000Z-140512T0245Z/
O'BRIEN IA-
925 PM CDT SUN MAY 11 2014

...THE TORNADO WARNING FOR NORTH CENTRAL O'BRIEN COUNTY IS
CANCELLED...

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

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 4320 9563 4317 9573 4321 9583 4326 9582
      4326 9580 4326 9569
TIME...MOT...LOC 0225Z 215DEG 18KT 4326 9574

$$

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, 8:14 PM CDT	Tornado Warning	FSD	Sioux	31 min
May 11, 8:42 PM CDT	Tornado Warning	FSD	O'Brien, Sioux	33 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.