Alert archive / Iowa / Tornado Warnings in 2012

Tornado Warning 10, NWS Sioux Falls, SD

April 21, 2012Dickinson County, Iowa; Jackson County, Minnesota

NWS Sioux Falls, SD issued this tornado warning at Apr 21, 2012, 4:38 PM CDT for Dickinson County, Iowa; Jackson County, Minnesota. It was in force for 37 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
Apr 21, 2012, 4:38 PM CDT (21:38 UTC)
Expired
Apr 21, 2012, 5:15 PM CDT
In force
37 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

Counties Dickinson County, IA, Jackson County, MN

The radar

The Sioux Falls radar (KFSD), 145 km from the middle of the area, began a volume at 21:38 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

Minneapolis, MN (KMPX), launched 12:00Z, 9.6 hours before the alert went out and 186 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, Minneapolis, MN at 12:00Z on 2012-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Minneapolis, MN at 12:00Z on 2012-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1566 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
85 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.

032 
WFUS53 KFSD 212138
TORFSD
IAC059-MNC063-212215-
/O.NEW.KFSD.TO.W.0010.120421T2138Z-120421T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
438 PM CDT SAT APR 21 2012

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHEASTERN DICKINSON COUNTY IN NORTHWEST IOWA...
  SOUTHEASTERN JACKSON COUNTY IN SOUTHWEST MINNESOTA...

* UNTIL 515 PM CDT

* AT 438 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD 6
  MILES NORTH OF ORLEANS...OR 7 MILES NORTH OF SPIRIT LAKE. A TORNADO
  MAY DEVELOP AT ANY TIME! DOPPLER RADAR SHOWED THIS TORNADIC STORM
  MOVING SOUTHEAST AT 30 MPH.

* THE TORNADO WILL BE NEAR...
  SUPERIOR AROUND 450 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 4350 9486 4349 9490 4329 9491 4351 9514
      4359 9506 4351 9484
TIME...MOT...LOC 2138Z 310DEG 25KT 4350 9505

$$

HANKO
2 follow-up statements
877 
WWUS53 KFSD 212153
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
453 PM CDT SAT APR 21 2012

IAC059-MNC063-212215-
/O.CON.KFSD.TO.W.0010.000000T0000Z-120421T2215Z/
DICKINSON IA-JACKSON MN-
453 PM CDT SAT APR 21 2012

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHEASTERN JACKSON AND
NORTHEASTERN DICKINSON COUNTIES UNTIL 515 PM CDT...

AT 453 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR SUPERIOR...OR 8 MILES EAST OF SPIRIT LAKE...
MOVING SOUTHEAST AT 30 MPH.

THIS TORNADO WILL AFFECT MAINLY RURAL AREAS OF NORTHEASTERN DICKINSON
AND SOUTHEASTERN JACKSON 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.

&&

LAT...LON 4346 9505 4354 9498 4351 9484 4350 9486
      4349 9490 4334 9491
TIME...MOT...LOC 2153Z 310DEG 25KT 4343 9494

$$

HANKO
960 
WWUS53 KFSD 212202
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
502 PM CDT SAT APR 21 2012

IAC059-MNC063-212213-
/O.CAN.KFSD.TO.W.0010.000000T0000Z-120421T2215Z/
DICKINSON IA-JACKSON MN-
502 PM CDT SAT APR 21 2012

...THE TORNADO WARNING FOR SOUTHEASTERN JACKSON AND NORTHEASTERN
DICKINSON COUNTIES IS CANCELLED...

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

LAT...LON 4346 9505 4354 9498 4351 9484 4350 9486
      4349 9490 4334 9491
TIME...MOT...LOC 2203Z 310DEG 25KT 4338 9487

$$

HANKO

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 4:21 PM CDTTornado WarningFSDClay24 min
Apr 21, 4:45 PM CDTTornado WarningFSDClay14 min
Apr 21, 4:00 PM CDTTornado WarningFSDJackson30 min

Nearby

Tornado Warnings in Iowa, 2012Tornado Warnings in Minnesota, 2012Every tornado warning in 2012Tornadoes in 2012

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.