Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 30, NWS Sioux Falls, SD

June 20, 2011Plymouth County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jun 20, 2011, 9:37 PM CDT for Plymouth County, Iowa. It was in force for 23 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
Jun 20, 2011, 9:37 PM CDT (02:37 UTC)
Expired
Jun 20, 2011, 10:00 PM CDT
In force
23 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

County Plymouth County, IA

The radar

The Sioux Falls radar (KFSD), 106 km from the middle of the area, began a volume at 02:39 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
Jun 20, 9:40 PM CDTTORNADO8 Nw Kingsley, IANUMEROUS FARM BUILDINGS AND GRAIN BINS DAMAGED.

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
Jun 20, 6:53 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 2.6 hours before the alert went out and 160 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 2011-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4194 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 2011-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 166 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
4194 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
898 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
166 m²/s²
0-3 km storm-relative helicity
182 m²/s²
Significant tornado parameter
4.6
Supercell composite
17.5

Open this sounding in Storm Lab

The text

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

406 
WFUS53 KFSD 210237
TORFSD
IAC149-210300-
/O.NEW.KFSD.TO.W.0030.110621T0237Z-110621T0300Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
937 PM CDT MON JUN 20 2011

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  EASTERN PLYMOUTH COUNTY IN NORTHWEST IOWA...

* UNTIL 1000 PM CDT

* AT 937 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
  DANGEROUS STORM WAS LOCATED 8 MILES NORTHWEST OF KINGSLEY...OR 10
  MILES SOUTH OF LE MARS...AND MOVING NORTH AT 40 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
  LE MARS AROUND 945 PM CDT...
  REMSEN AROUND 955 PM CDT...

OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDE OYENS.

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 4291 9617 4290 9591 4259 9600 4256 9616
      4262 9625
TIME...MOT...LOC 0237Z 195DEG 34KT 4268 9608

$$

LIEBL
2 follow-up statements
849 
WWUS53 KFSD 210244
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
944 PM CDT MON JUN 20 2011

IAC149-210300-
/O.CON.KFSD.TO.W.0030.000000T0000Z-110621T0300Z/
PLYMOUTH IA-
944 PM CDT MON JUN 20 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR EASTERN PLYMOUTH COUNTY
UNTIL 1000 PM CDT...

AT 945 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED 6 MILES SOUTHWEST OF REMSEN...OR 7 MILES SOUTHEAST
OF LE MARS...MOVING NORTH AT 40 MPH.

THIS DANGEROUS STORM WILL BE NEAR...
  REMSEN AROUND 955 PM CDT...

OTHER LOCATIONS IMPACTED BY THIS TORNADO INCLUDE OYENS.

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 4269 9598 4264 9609 4273 9622 4291 9617
      4290 9591
TIME...MOT...LOC 0245Z 195DEG 34KT 4275 9605

$$

LIEBL
824 
WWUS53 KFSD 210255
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
955 PM CDT MON JUN 20 2011

IAC149-210305-
/O.EXP.KFSD.TO.W.0030.000000T0000Z-110621T0300Z/
PLYMOUTH IA-
955 PM CDT MON JUN 20 2011

...THE TORNADO WARNING FOR EASTERN PLYMOUTH COUNTY WILL EXPIRE AT
1000 PM CDT...

THE TORNADO THREAT HAS DIMINISHED...THEREFORE THE TORNADO WARNING HAS
EXPIRED. HOWEVER...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT
FOR THE AREA...HOWEVER GUSTY WINDS AND HEAVY RAIN ARE STILL POSSIBLE
WITH THIS THUNDERSTORM.

LAT...LON 4269 9598 4264 9609 4273 9622 4291 9617
      4290 9591
TIME...MOT...LOC 0255Z 195DEG 34KT 4284 9602

$$

LIEBL

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 20, 9:12 PM CDTSevere Thunderstorm WarningFSDCherokee, Ida, Plymouth, Woodbury33 min
Jun 20, 9:18 PM CDTFlash Flood WarningFSDPlymouth, Sioux, Woodbury2 hr
Jun 20, 9:34 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Cherokee, Clay, Ida, O'Brien, Plymouth and 1 more41 min
Jun 20, 9:39 PM CDTFlash Flood WarningFSDLyon, Sioux3 hr
Jun 20, 10:14 PM CDTSevere Thunderstorm WarningFSDClay, Dickinson, Lyon, O'Brien, Osceola, Sioux46 min
Jun 20, 10:20 PM CDTSevere Thunderstorm WarningFSDBuena Vista40 min
Jun 20, 10:22 PM CDTTornado WarningFSDClay, Dickinson, O'Brien, Osceola23 min
Jun 20, 10:38 PM CDTTornado WarningFSDDickinson, Osceola37 min
Jun 20, 10:46 PM CDTSevere Thunderstorm WarningFSDClay, Dickinson, Lyon, Osceola29 min
Jun 21, 12:55 AM CDTRiver Flood WarningFSDClay, Dickinson9 days
Jun 21, 12:55 AM CDTRiver Flood WarningFSDCherokee11 days
Jun 21, 12:55 AM CDTRiver Flood WarningFSDLyon5 days
Jun 21, 12:55 AM CDTRiver Flood WarningFSDClay6 days
Jun 21, 6:34 AM CDTRiver Flood WarningFSDLyon14 hr
Jun 21, 6:34 AM CDTRiver Flood WarningFSDO'Brien30 hr
Jun 21, 6:34 AM CDTRiver Flood WarningFSDSioux30 hr

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.