Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 10, NWS Sioux Falls, SD

April 9, 2011Buena Vista County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Apr 9, 2011, 10:02 PM CDT for Buena Vista County, Iowa. It was in force for 28 min. 1 report 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: Apr 9, 2011, 10:02 PM CDT (03:02 UTC)
Expired: Apr 9, 2011, 10:30 PM CDT
In force: 28 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon

County Buena Vista County, IA

The radar

The Des Moines radar (KDMX), 156 km from the middle of the area, began a volume at 03:04 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
Apr 9, 10:04 PM CDT	HAIL 1.75	Truesdale, IA

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.

Issued	Product	Office	Lasted
Apr 9, 5:48 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 3.0 hours before the alert went out and 185 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: 3327 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 1533 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 270 m²/s²
0-3 km storm-relative helicity: 403 m²/s²
Significant tornado parameter: 3.7
Supercell composite: 19.0

Open this sounding in Storm Lab

The text

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

435 
WFUS53 KFSD 100302
TORFSD
IAC021-100330-
/O.NEW.KFSD.TO.W.0010.110410T0302Z-110410T0330Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1002 PM CDT SAT APR 9 2011

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL BUENA VISTA COUNTY IN NORTHWEST IOWA...

* UNTIL 1030 PM CDT

* AT 1001 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
  DANGEROUS STORM WAS LOCATED NEAR STORM LAKE...AND MOVING NORTHEAST
  AT 20 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
  TRUESDALE AROUND 1010 PM CDT...
  ALBERT CITY AROUND 1030 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.

THIS WARNING REPLACES THE PREVIOUSLY ISSUED TORNADO WARNING.
&&

LAT...LON 4261 9521 4271 9527 4287 9494 4266 9492
TIME...MOT...LOC 0301Z 247DEG 16KT 4267 9520

$$

CJ

2 follow-up statements

406 
WWUS53 KFSD 100318
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1018 PM CDT SAT APR 9 2011

IAC021-100330-
/O.CON.KFSD.TO.W.0010.000000T0000Z-110410T0330Z/
BUENA VISTA IA-
1018 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR EAST CENTRAL BUENA VISTA
COUNTY UNTIL 1030 PM CDT...

AT 1018 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS
DANGEROUS STORM WAS LOCATED 5 MILES NORTH OF NEWELL...OR 10 MILES
EAST OF STORM LAKE...MOVING EAST AT 45 MPH.

THIS DANGEROUS STORM WILL BE NEAR...
  ALBERT CITY AROUND 1025 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 4264 9503 4263 9510 4274 9511 4280 9493
      4266 9492
TIME...MOT...LOC 0318Z 265DEG 39KT 4269 9501

$$

CJ

300 
WWUS53 KFSD 100327
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1027 PM CDT SAT APR 9 2011

IAC021-100338-
/O.EXP.KFSD.TO.W.0010.000000T0000Z-110410T0330Z/
BUENA VISTA IA-
1027 PM CDT SAT APR 9 2011

...THE TORNADO WARNING FOR EAST CENTRAL BUENA VISTA COUNTY WILL
EXPIRE AT 1030 PM CDT...

THE STORM WHICH PROMPTED THE WARNING WAS MOVING OUT OF THE WARNED
AREA.

LAT...LON 4264 9503 4263 9510 4274 9511 4280 9493
      4266 9492
TIME...MOT...LOC 0328Z 265DEG 39KT 4270 9486

$$

CJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 9, 7:09 PM CDT	Severe Thunderstorm Warning	FSD	Ida, Woodbury	36 min
Apr 9, 7:31 PM CDT	Tornado Warning	FSD	Ida	29 min
Apr 9, 7:44 PM CDT	Severe Thunderstorm Warning	FSD	Ida	31 min
Apr 9, 7:46 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Ida, Woodbury	29 min
Apr 9, 7:56 PM CDT	Tornado Warning	FSD	Ida	34 min
Apr 9, 8:08 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Cherokee, Ida, Woodbury	37 min
Apr 9, 8:11 PM CDT	Severe Thunderstorm Warning	FSD	Ida	34 min
Apr 9, 8:19 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Woodbury	41 min
Apr 9, 8:40 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee	35 min
Apr 9, 8:41 PM CDT	Severe Thunderstorm Warning	FSD	Ida	19 min
Apr 9, 8:49 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	41 min
Apr 9, 8:55 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Woodbury	35 min
Apr 9, 9:08 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee	37 min
Apr 9, 9:09 PM CDT	Tornado Warning	FSD	Buena Vista	36 min
Apr 9, 9:15 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Sioux	30 min
Apr 9, 9:17 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Woodbury	43 min
Apr 9, 9:24 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth, Woodbury	36 min
Apr 9, 9:25 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	20 min
Apr 9, 9:31 PM CDT	Tornado Warning	FSD	Plymouth, Woodbury	29 min
Apr 9, 9:36 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Cherokee, Clay	39 min
Apr 9, 9:46 PM CDT	Tornado Warning	FSD	Buena Vista	29 min
Apr 9, 9:48 PM CDT	Tornado Warning	FSD	Cherokee	27 min
Apr 9, 9:58 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth	32 min
Apr 9, 10:09 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	36 min
Apr 9, 10:13 PM CDT	Tornado Warning	FSD	Buena Vista, Cherokee	47 min
Apr 9, 10:24 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, O'Brien, Plymouth, Sioux	36 min
Apr 9, 10:31 PM CDT	Tornado Warning	FSD	Cherokee	29 min
Apr 9, 10:35 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	30 min
Apr 9, 10:50 PM CDT	Tornado Warning	FSD	Buena Vista, Cherokee	40 min
Apr 9, 11:11 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista, Clay	34 min
Apr 9, 11:27 PM CDT	Tornado Warning	FSD	Buena Vista, Clay	18 min
Apr 9, 11:39 PM CDT	Tornado Warning	FSD	Clay	21 min
Apr 10, 12:24 AM CDT	Severe Thunderstorm Warning	FSD	Woodbury	36 min
Apr 10, 12:47 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Ida	28 min

Nearby

Tornado Warnings in Iowa, 2011 Every tornado warning in 2011 Tornadoes in 2011

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.