Alert archive / Iowa / Tornado Warnings in 2015

Tornado Warning 34, NWS Sioux Falls, SD

October 23, 2015O'Brien County, Osceola County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Oct 23, 2015, 6:44 PM CDT for O'Brien County, Osceola 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 outline as issued.

The facts

Issued: Oct 23, 2015, 6:44 PM CDT (23:44 UTC)
Expired: Oct 23, 2015, 7:15 PM CDT
In force: 31 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties O'Brien County, IA, Osceola County, IA

The radar

The Sioux Falls radar (KFSD), 92 km from the middle of the area, began a volume at 23:45 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 12:00Z, 11.7 hours before the alert went out and 222 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: 28 J/kg
Mixed-layer CIN: -74 J/kg
Mixed-layer LCL: 554 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 240 m²/s²
0-3 km storm-relative helicity: 233 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.

687 
WFUS53 KFSD 232344
TORFSD
IAC141-143-240015-
/O.NEW.KFSD.TO.W.0034.151023T2344Z-151024T0015Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
644 PM CDT FRI OCT 23 2015

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTH CENTRAL OSCEOLA COUNTY IN NORTHWESTERN IOWA...
  NORTHWESTERN O'BRIEN COUNTY IN NORTHWESTERN IOWA...

* UNTIL 715 PM CDT
    
* AT 644 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS LOCATED NEAR SANBORN...OR NEAR SHELDON...MOVING
  NORTHEAST AT 20 MPH.

  HAZARD...TORNADO. 

  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...
  MELVIN AROUND 705 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4317 9576 4326 9579 4341 9563 4327 9552
TIME...MOT...LOC 2344Z 223DEG 17KT 4323 9573 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

WEISSER

2 follow-up statements

512 
WWUS53 KFSD 232359
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
659 PM CDT FRI OCT 23 2015

IAC141-143-240015-
/O.CON.KFSD.TO.W.0034.000000T0000Z-151024T0015Z/
OSCEOLA IA-O'BRIEN IA-
659 PM CDT FRI OCT 23 2015

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 715 PM CDT FOR SOUTH
CENTRAL OSCEOLA AND NORTH CENTRAL O'BRIEN COUNTIES...
    
AT 659 PM CDT...A THUNDERSTORM WITH A HISTORY OF TORNADOES WAS
LOCATED WEST OF MELVIN...OR 9 MILES SOUTHEAST OF SIBLEY...MOVING
NORTHEAST AT 20 MPH.

HAZARD...DAMAGING TORNADO. 

SOURCE...LAW ENFORCEMENT 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. 

THIS TORNADO WILL BE NEAR...
  MELVIN AROUND 705 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4321 9574 4326 9579 4341 9563 4327 9552
TIME...MOT...LOC 2359Z 223DEG 17KT 4328 9566 

TORNADO...OBSERVED
HAIL...<.75IN

$$

WEISSER

508 
WWUS53 KFSD 240012
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
712 PM CDT FRI OCT 23 2015

IAC141-143-240021-
/O.EXP.KFSD.TO.W.0034.000000T0000Z-151024T0015Z/
OSCEOLA IA-O'BRIEN IA-
712 PM CDT FRI OCT 23 2015

...THE TORNADO WARNING FOR SOUTH CENTRAL OSCEOLA AND NORTH CENTRAL
O'BRIEN COUNTIES WILL EXPIRE AT 715 PM CDT...
    
THE TORNADIC THUNDERSTORM WHICH PROMPTED THE WARNING HAS WEAKENED.
THEREFORE THE WARNING WILL BE ALLOWED TO EXPIRE. HEAVY RAIN WILL
STILL BE POSSIBLE WITH THIS STORM AS IT MOVES NORTHEAST.

LAT...LON 4321 9574 4326 9579 4341 9563 4327 9552
TIME...MOT...LOC 0011Z 223DEG 17KT 4328 9566 

$$

WEISSER

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 23, 5:43 PM CDT	Tornado Warning Tornado observed	FSD	Sioux	32 min
Oct 23, 5:45 PM CDT	Tornado Warning	FSD	Cherokee	30 min
Oct 23, 5:47 PM CDT	Tornado Warning	FSD	Plymouth	28 min
Oct 23, 6:08 PM CDT	Tornado Warning Tornado observed	FSD	O'Brien	37 min
Oct 23, 6:12 PM CDT	Tornado Warning	FSD	Plymouth, Sioux	33 min
Oct 23, 6:16 PM CDT	Tornado Warning	FSD	Cherokee, O'Brien	29 min
Oct 23, 6:42 PM CDT	Tornado Warning Tornado observed	FSD	O'Brien	14 min

Nearby

Tornado Warnings in Iowa, 2015 Every tornado warning in 2015 Tornadoes in 2015

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.