Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 4, NWS Omaha, NE

March 22, 2011Harrison County, Pottawattamie County, Iowa

NWS Omaha, NE issued this tornado warning at Mar 22, 2011, 5:03 PM CDT for Harrison County, Pottawattamie County, Iowa. It was in force for 27 min. 2 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
Mar 22, 2011, 5:03 PM CDT (22:03 UTC)
Expired
Mar 22, 2011, 5:30 PM CDT
In force
27 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon

Counties Harrison County, IA, Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 63 km from the middle of the area, began a volume at 22:04 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
Mar 22, 5:03 PM CDTHAIL 11 Ne Missouri Valley, IAWALL CLOUD SPOTTED WITH STORM.
Mar 22, 5:04 PM CDTHAIL 1.755 E Missouri Valley, IA

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
Mar 22, 2:03 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.1 hours before the alert went out and 63 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°0°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.

590 
WFUS53 KOAX 222203
TOROAX
IAC085-155-222230-
/O.NEW.KOAX.TO.W.0004.110322T2203Z-110322T2230Z/

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

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHERN HARRISON COUNTY IN SOUTHWEST IOWA...
  NORTHWESTERN POTTAWATTAMIE COUNTY IN SOUTHWEST IOWA...

* UNTIL 530 PM CDT

* AT 500 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO 2      
  MILES EAST OF MISSOURI VALLEY...OR 23 MILES NORTHEAST OF OMAHA.  
  DOPPLER RADAR SHOWED THIS TORNADO MOVING NORTHEAST AT 50 MPH.

* LOCATIONS IMPACTED INCLUDE...
  LOGAN...PERSIA AND WOODBINE.

THE WARNED AREA INCLUDES INTERSTATE 29 IN IOWA BETWEEN MILE MARKERS
72 AND 75.

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 4145 9587 4161 9598 4181 9556 4160 9556
      4160 9553 4155 9550
TIME...MOT...LOC 2203Z 243DEG 29KT 4158 9581

$$

FOBERT
2 follow-up statements
921 
WWUS53 KOAX 222209
SVSOAX

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

IAC155-222217-
/O.CAN.KOAX.TO.W.0004.000000T0000Z-110322T2230Z/
POTTAWATTAMIE IA-
509 PM CDT TUE MAR 22 2011

...THE TORNADO WARNING FOR NORTHWESTERN POTTAWATTAMIE COUNTY IS
CANCELLED...

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

LAT...LON 4151 9589 4161 9598 4181 9556 4160 9556
      4160 9553 4155 9550
TIME...MOT...LOC 2207Z 243DEG 29KT 4161 9575

$$

IAC085-222230-
/O.CON.KOAX.TO.W.0004.000000T0000Z-110322T2230Z/
HARRISON IA-
509 PM CDT TUE MAR 22 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHERN HARRISON COUNTY
UNTIL 530 PM CDT...

AT 504 PM CDT...TRAINED WEATHER SPOTTERS REPORTED GOLF BALL SIZE 
HAIL 5 MILES EAST OF MISSOURI VALLEY.  THIS STORM EARLIER PRODUCED A 
TORNADO THAT WAS ON THE GROUND FOR AROUND 7 MINUTES FROM 455 UNTIL 
502 PM.  THIS STORM WAS 26 MILES NORTHEAST OF OMAHA...MOVING 
NORTHEAST AT 45 MPH.

LOCATIONS IMPACTED INCLUDE...
  PERSIA AND WOODBINE.

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 4151 9589 4161 9598 4181 9556 4160 9556
      4160 9553 4155 9550
TIME...MOT...LOC 2207Z 243DEG 29KT 4161 9575

$$

FOBERT
905 
WWUS53 KOAX 222215
SVSOAX

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

IAC085-222230-
/O.CON.KOAX.TO.W.0004.000000T0000Z-110322T2230Z/
HARRISON IA-
515 PM CDT TUE MAR 22 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHERN HARRISON COUNTY
UNTIL 530 PM CDT...

AT 514 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO 2 TO 3 
MILES EAST OF LOGAN...OR 30 MILES NORTHEAST OF OMAHA...MOVING 
NORTHEAST AT 35 MPH.

LOCATIONS IMPACTED INCLUDE...
  PERSIA.

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 4151 9589 4161 9598 4181 9556 4160 9556
      4160 9553 4155 9550
TIME...MOT...LOC 2214Z 243DEG 29KT 4166 9566

$$

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, 5:08 PM CDTTornado WarningOAXMontgomery22 min
Mar 22, 5:19 PM CDTTornado WarningOAXShelby26 min
Mar 22, 5:31 PM CDTTornado WarningOAXHarrison, Shelby29 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.