Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 7, NWS Omaha, NE

March 22, 2011Harrison County, Shelby County, Iowa

NWS Omaha, NE issued this tornado warning at Mar 22, 2011, 5:31 PM CDT for Harrison County, Shelby County, Iowa. It was in force for 29 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
Mar 22, 2011, 5:31 PM CDT (22:31 UTC)
Expired
Mar 22, 2011, 6:00 PM CDT
In force
29 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon

Counties Harrison County, IA, Shelby County, IA

The radar

The Omaha radar (KOAX), 87 km from the middle of the area, began a volume at 22:33 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Mar 22, 2:03 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.5 hours before the alert went out and 87 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 12:00Z on 2011-03-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 486 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, Omaha, NE at 12:00Z on 2011-03-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 477 square meters per square second.1939587897Sfc1 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
486 J/kg
Mixed-layer CIN
-475 J/kg
Mixed-layer LCL
777 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
477 m²/s²
0-3 km storm-relative helicity
501 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.

267 
WFUS53 KOAX 222231
TOROAX
IAC085-165-222300-
/O.NEW.KOAX.TO.W.0007.110322T2231Z-110322T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
531 PM CDT TUE MAR 22 2011

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHEASTERN HARRISON COUNTY IN SOUTHWEST IOWA...
  NORTHWESTERN SHELBY COUNTY IN SOUTHWEST IOWA...

* UNTIL 600 PM CDT

* AT 528 PM CDT...WEATHER SERVICE METEOROLOGISTS DETECTED A 
  A TORNADO 8 MILES WEST OF EARLING...OR 41 MILES NORTHEAST OF       
  OMAHA. DOPPLER RADAR SHOWED THIS TORNADO MOVING NORTHEAST AT 40    
  MPH.

* LOCATIONS IMPACTED INCLUDE...
  EARLING...DEFIANCE AND WESTPHALIA.

THE WARNED AREA INCLUDES HIGHWAY 59 IN IOWA BETWEEN MILE MARKERS 85 
AND 91.  THIS WARNING REPLACES THE WARNING ISSUED EARLIER FOR SHELBY 
COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A TORNADO IS ON THE GROUND. 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 4160 9556 4179 9560 4186 9556 4186 9514
TIME...MOT...LOC 2230Z 219DEG 34KT 4177 9556

$$

FOBERT
2 follow-up statements
654 
WWUS53 KOAX 222239
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
539 PM CDT TUE MAR 22 2011

IAC085-222249-
/O.CAN.KOAX.TO.W.0007.000000T0000Z-110322T2300Z/
HARRISON IA-
539 PM CDT TUE MAR 22 2011

...THE TORNADO WARNING FOR NORTHEASTERN HARRISON COUNTY IS
CANCELLED...

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

LAT...LON 4160 9556 4186 9556 4186 9514
TIME...MOT...LOC 2239Z 219DEG 34KT 4183 9547

$$

IAC165-222300-
/O.CON.KOAX.TO.W.0007.000000T0000Z-110322T2300Z/
SHELBY IA-
539 PM CDT TUE MAR 22 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHWESTERN SHELBY COUNTY
UNTIL 600 PM CDT...

AT 538 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS
DANGEROUS STORM WAS LOCATED NEAR EARLING...OR 48 MILES NORTHEAST OF
OMAHA...MOVING NORTHEAST AT 40 MPH.

LOCATIONS IMPACTED INCLUDE...
  DEFIANCE.

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 4160 9556 4186 9556 4186 9514
TIME...MOT...LOC 2239Z 219DEG 34KT 4183 9547

$$

FOBERT
092 
WWUS53 KOAX 222256
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
556 PM CDT TUE MAR 22 2011

IAC165-222306-
/O.EXP.KOAX.TO.W.0007.000000T0000Z-110322T2300Z/
SHELBY IA-
556 PM CDT TUE MAR 22 2011

...THE TORNADO WARNING FOR NORTHWESTERN SHELBY COUNTY WILL EXPIRE AT
600 PM CDT...

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

LAT...LON 4160 9556 4186 9556 4186 9514
TIME...MOT...LOC 2256Z 219DEG 34KT 4195 9533

$$

FOBERT

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 22, 4:10 PM CDTSevere Thunderstorm WarningOAXFremont, Mills50 min
Mar 22, 4:48 PM CDTSevere Thunderstorm WarningOAXHarrison42 min
Mar 22, 4:53 PM CDTTornado WarningOAXHarrison37 min
Mar 22, 4:57 PM CDTSevere Thunderstorm WarningOAXMontgomery, Pottawattamie33 min
Mar 22, 5:03 PM CDTTornado WarningOAXHarrison, Pottawattamie27 min
Mar 22, 5:08 PM CDTTornado WarningOAXMontgomery22 min
Mar 22, 5:19 PM CDTTornado WarningOAXShelby26 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.