Alert archive / South Dakota / Tornado Warnings in 2011

Tornado Warning 41, NWS Sioux Falls, SD

August 22, 2011Lake County, Minnehaha County, Moody County, South Dakota

NWS Sioux Falls, SD issued this tornado warning at Aug 22, 2011, 11:41 PM CDT for Lake County, Minnehaha County, Moody County, South Dakota. It was in force for 34 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
Aug 22, 2011, 11:41 PM CDT (04:41 UTC)
Expired
Aug 23, 2011, 12:15 AM CDT
In force
34 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

Counties Lake County, SD, Minnehaha County, SD, Moody County, SD

The radar

The Sioux Falls radar (KFSD), 31 km from the middle of the area, began a volume at 04:44 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
Aug 22, 11:55 PM CDTHAIL 0.5Chester, SD

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 4.7 hours before the alert went out and 169 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, Aberdeen, SD at 00:00Z on 2011-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2620 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 00:00Z on 2011-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 86 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
2620 J/kg
Mixed-layer CIN
-134 J/kg
Mixed-layer LCL
1327 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
86 m²/s²
0-3 km storm-relative helicity
107 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.8

Open this sounding in Storm Lab

The text

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

250 
WFUS53 KFSD 230441
TORFSD
SDC079-099-101-230515-
/O.NEW.KFSD.TO.W.0041.110823T0441Z-110823T0515Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1141 PM CDT MON AUG 22 2011

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHEASTERN LAKE COUNTY IN EAST CENTRAL SOUTH DAKOTA...
  NORTHWESTERN MINNEHAHA COUNTY IN SOUTHEAST SOUTH DAKOTA...
  SOUTHWESTERN MOODY COUNTY IN EAST CENTRAL SOUTH DAKOTA...

* UNTIL 1215 AM CDT

* AT 1141 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
  DANGEROUS STORM WAS LOCATED 6 MILES WEST OF COLTON...OR 15 MILES
  SOUTH OF MADISON...AND MOVING SOUTHEAST AT 25 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
  COLTON AROUND 1155 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.

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

&&

LAT...LON 4391 9668 4365 9683 4380 9713 4397 9704
TIME...MOT...LOC 0441Z 296DEG 21KT 4379 9704

$$

HANKO
1 follow-up statement
441 
WWUS53 KFSD 230459
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1159 PM CDT MON AUG 22 2011

SDC079-230509-
/O.CAN.KFSD.TO.W.0041.000000T0000Z-110823T0515Z/
LAKE SD-
1159 PM CDT MON AUG 22 2011

...THE TORNADO WARNING FOR SOUTHEASTERN LAKE COUNTY IS CANCELLED...

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

LAT...LON 4394 9688 4391 9668 4365 9683 4375 9698
      4385 9693 4385 9689 4393 9689
TIME...MOT...LOC 0459Z 296DEG 21KT 4374 9691

$$

SDC099-101-230515-
/O.CON.KFSD.TO.W.0041.000000T0000Z-110823T0515Z/
MOODY SD-MINNEHAHA SD-
1159 PM CDT MON AUG 22 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTH CENTRAL MINNEHAHA
AND SOUTHWESTERN MOODY COUNTIES UNTIL 1215 AM CDT...

AT 1159 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS
DANGEROUS STORM WAS LOCATED NEAR COLTON...OR 17 MILES NORTHWEST OF
SIOUX FALLS...MOVING SOUTHEAST AT 25 MPH.

THIS TORNADO WILL AFFECT MAINLY RURAL AREAS OF NORTH CENTRAL
MINNEHAHA AND SOUTHWESTERN MOODY COUNTIES.

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.

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

&&

LAT...LON 4394 9688 4391 9668 4365 9683 4375 9698
      4385 9693 4385 9689 4393 9689
TIME...MOT...LOC 0459Z 296DEG 21KT 4374 9691

$$

HANKO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 22, 9:43 PM CDTSevere Thunderstorm WarningFSDLake, McCook, Miner47 min
Aug 22, 10:17 PM CDTSevere Thunderstorm WarningFSDLake, McCook, Minnehaha, Moody43 min
Aug 22, 10:27 PM CDTSevere Thunderstorm WarningFSDLake, Miner33 min
Aug 22, 10:56 PM CDTSevere Thunderstorm WarningFSDLake, Miner49 min
Aug 22, 11:11 PM CDTTornado WarningFSDLake, McCook, Minnehaha34 min
Aug 22, 11:23 PM CDTSevere Thunderstorm WarningFSDMinnehaha, Moody52 min
Aug 23, 12:12 AM CDTSevere Thunderstorm WarningFSDMinnehaha48 min
Aug 23, 3:43 AM CDTHeat AdvisoryFSDBon Homme, Clay, Hutchinson, Lincoln, Turner, Union and 1 more11 hr

Nearby

Tornado Warnings in South Dakota, 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.