Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 6, NWS Sioux Falls, SD

April 9, 2011Buena Vista County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Apr 9, 2011, 9:09 PM CDT for Buena Vista County, Iowa. It was in force for 36 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
Apr 9, 2011, 9:09 PM CDT (02:09 UTC)
Expired
Apr 9, 2011, 9:45 PM CDT
In force
36 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

County Buena Vista County, IA

The radar

The Des Moines radar (KDMX), 142 km from the middle of the area, began a volume at 02:09 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
Apr 9, 9:09 PM CDTTORNADO4 N Nemaha, IALARGE WEDGE TORNADO
Apr 9, 9:14 PM CDTTORNADO5 Wsw Newell, IARELAYED FROM SPOTTER NETWORK
Apr 9, 9:25 PM CDTTORNADO4 Se Newell, IADAMAGE TO FARMSTEAD. RATED EF2.

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
Apr 9, 5:48 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.2 hours before the alert went out and 184 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 00:00Z on 2011-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3327 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2011-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 270 square meters per square second.19395878Sfc1 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
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.

225 
WFUS53 KFSD 100209
TORFSD
IAC021-100245-
/O.NEW.KFSD.TO.W.0006.110410T0209Z-110410T0245Z/

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

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

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

* UNTIL 945 PM CDT

* AT 909 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
  DANGEROUS STORM WAS LOCATED 7 MILES SOUTH OF LAKESIDE...OR 9 MILES
  SOUTH OF STORM LAKE...AND MOVING NORTHEAST AT 20 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
  NEWELL AROUND 935 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 4255 9492 4256 9518 4257 9517 4272 9492
      4271 9491 4265 9491 4256 9491
TIME...MOT...LOC 0209Z 236DEG 16KT 4254 9511

$$

CJ
4 follow-up statements
410 
WWUS53 KFSD 100220
SVSFSD

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

IAC021-100245-
/O.CON.KFSD.TO.W.0006.000000T0000Z-110410T0245Z/
BUENA VISTA IA-
920 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHEASTERN BUENA VISTA
COUNTY UNTIL 945 PM CDT...

AT 921 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR NEWELL...OR 11 MILES SOUTHEAST OF STORM
LAKE...MOVING NORTHEAST AT 20 MPH.

THIS TORNADO WILL AFFECT MAINLY RURAL AREAS OF SOUTHEASTERN BUENA
VISTA COUNTY.

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 4255 9492 4256 9518 4257 9517 4272 9492
      4271 9491 4265 9491 4256 9491
TIME...MOT...LOC 0221Z 240DEG 19KT 4257 9499

$$

CJ
712 
WWUS53 KFSD 100226 CCA
SVSFSD

SEVERE WEATHER STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE SIOUX FALLS SD
920 PM CDT SAT APR 9 2011

IAC021-100245-
/O.COR.KFSD.TO.W.0006.000000T0000Z-110410T0245Z/
BUENA VISTA IA-
920 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHEASTERN BUENA VISTA
COUNTY UNTIL 945 PM CDT...

AT 920 PM CDT...A TORNADO WAS REPORTED...PRODUCING.  THIS TORNADO WAS
LOCATED NEAR NEWELL...OR 13 MILES SOUTHEAST OF STORM LAKE...MOVING
NORTHEAST AT 20 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 4255 9492 4256 9518 4257 9517 4272 9492
      4271 9491 4265 9491 4256 9491
TIME...MOT...LOC 0220Z 240DEG 19KT 4257 9498

$$
203 
WWUS53 KFSD 100229
SVSFSD

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

IAC021-100245-
/O.CON.KFSD.TO.W.0006.000000T0000Z-110410T0245Z/
BUENA VISTA IA-
929 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHEASTERN BUENA VISTA
COUNTY UNTIL 945 PM CDT...

AT 929 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR NEWELL...OR 14 MILES EAST OF STORM LAKE...
MOVING NORTHEAST AT 20 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 4255 9492 4256 9518 4257 9517 4272 9492
      4271 9491 4265 9491 4256 9491
TIME...MOT...LOC 0229Z 240DEG 19KT 4259 9492

$$

CJ
315 
WWUS53 KFSD 100240
SVSFSD

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

IAC021-100250-
/O.EXP.KFSD.TO.W.0006.000000T0000Z-110410T0245Z/
BUENA VISTA IA-
940 PM CDT SAT APR 9 2011

...THE TORNADO WARNING FOR SOUTHEASTERN BUENA VISTA COUNTY WILL
EXPIRE AT 945 PM CDT...

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

LAT...LON 4255 9492 4256 9518 4257 9517 4272 9492
      4271 9491 4265 9491 4256 9491
TIME...MOT...LOC 0240Z 240DEG 19KT 4262 9485

$$

CJ

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 7:09 PM CDTSevere Thunderstorm WarningFSDIda, Woodbury36 min
Apr 9, 7:31 PM CDTTornado WarningFSDIda29 min
Apr 9, 7:44 PM CDTSevere Thunderstorm WarningFSDIda31 min
Apr 9, 7:46 PM CDTSevere Thunderstorm WarningFSDCherokee, Ida, Woodbury29 min
Apr 9, 7:56 PM CDTTornado WarningFSDIda34 min
Apr 9, 8:08 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Cherokee, Ida, Woodbury37 min
Apr 9, 8:11 PM CDTSevere Thunderstorm WarningFSDIda34 min
Apr 9, 8:19 PM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury41 min
Apr 9, 8:40 PM CDTSevere Thunderstorm WarningFSDCherokee35 min
Apr 9, 8:41 PM CDTSevere Thunderstorm WarningFSDIda19 min
Apr 9, 8:49 PM CDTSevere Thunderstorm WarningFSDBuena Vista41 min
Apr 9, 8:55 PM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury35 min
Apr 9, 9:08 PM CDTSevere Thunderstorm WarningFSDCherokee37 min
Apr 9, 9:15 PM CDTSevere Thunderstorm WarningFSDPlymouth, Sioux30 min
Apr 9, 9:17 PM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury43 min
Apr 9, 9:24 PM CDTSevere Thunderstorm WarningFSDCherokee, Plymouth, Woodbury36 min
Apr 9, 9:25 PM CDTSevere Thunderstorm WarningFSDBuena Vista20 min
Apr 9, 9:31 PM CDTTornado WarningFSDPlymouth, Woodbury29 min
Apr 9, 9:36 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Cherokee, Clay39 min
Apr 9, 9:46 PM CDTTornado WarningFSDBuena Vista29 min
Apr 9, 9:48 PM CDTTornado WarningFSDCherokee27 min
Apr 9, 9:58 PM CDTSevere Thunderstorm WarningFSDPlymouth32 min
Apr 9, 10:02 PM CDTTornado WarningFSDBuena Vista28 min
Apr 9, 10:09 PM CDTSevere Thunderstorm WarningFSDBuena Vista36 min
Apr 9, 10:13 PM CDTTornado WarningFSDBuena Vista, Cherokee47 min
Apr 9, 10:24 PM CDTSevere Thunderstorm WarningFSDCherokee, O'Brien, Plymouth, Sioux36 min
Apr 9, 10:31 PM CDTTornado WarningFSDCherokee29 min
Apr 9, 10:35 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Clay30 min
Apr 9, 10:50 PM CDTTornado WarningFSDBuena Vista, Cherokee40 min
Apr 9, 11:11 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Clay34 min
Apr 9, 11:27 PM CDTTornado WarningFSDBuena Vista, Clay18 min
Apr 9, 11:39 PM CDTTornado WarningFSDClay21 min
Apr 10, 12:24 AM CDTSevere Thunderstorm WarningFSDWoodbury36 min
Apr 10, 12:47 AM CDTSevere Thunderstorm WarningFSDCherokee, Ida28 min

Nearby

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