Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 9, NWS Omaha, NE

April 9, 2011Monona County, Iowa

NWS Omaha, NE issued this tornado warning at Apr 9, 2011, 6:39 PM CDT for Monona County, Iowa. It was in force for 35 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 9, 2011, 6:39 PM CDT (23:39 UTC)
Expired: Apr 9, 2011, 7:14 PM CDT
In force: 35 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon

County Monona County, IA

The radar

The Omaha radar (KOAX), 89 km from the middle of the area, began a volume at 23:38 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 watch it was issued in

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

Issued	Product	Office	Lasted
Apr 9, 5:48 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.7 hours before the alert went out and 89 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 462 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 354 m²/s²
0-3 km storm-relative helicity: 338 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.5

Open this sounding in Storm Lab

The text

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

581 
WFUS53 KOAX 092339
TOROAX
IAC133-100030-
/O.NEW.KOAX.TO.W.0009.110409T2339Z-110410T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
639 PM CDT SAT APR 9 2011

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* TORNADO WARNING FOR...
  WESTERN MONONA COUNTY IN WEST CENTRAL IOWA...

* UNTIL 730 PM CDT

* AT 633 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
  STORM WAS LOCATED NEAR WHITING...OR 30 MILES SOUTH OF SIOUX CITY...
  AND MOVING SOUTHEAST AT 15 MPH.

* LOCATIONS IMPACTED INCLUDE...
  WHITING...ONAWA...LEWIS AND CLARK STATE PARK...KENNEBEC...TURIN AND
  CASTANA.

THE WARNED AREA INCLUDES INTERSTATE 29 IN IOWA BETWEEN MILE MARKERS
112 AND 120.

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 4214 9591 4201 9585 4196 9600 4207 9627
      4213 9623
TIME...MOT...LOC 2339Z 298DEG 13KT 4208 9619

$$

NIETFELD

4 follow-up statements

919 
WWUS53 KOAX 092348
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
648 PM CDT SAT APR 9 2011

IAC133-100030-
/O.CON.KOAX.TO.W.0009.000000T0000Z-110410T0030Z/
MONONA IA-
648 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL MONONA COUNTY
UNTIL 730 PM CDT...

AT 643 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS
DANGEROUS STORM WAS LOCATED NEAR WHITING...OR 31 MILES SOUTHEAST OF
SIOUX CITY...MOVING EAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
  ONAWA...KENNEBEC...TURIN AND CASTANA.

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.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN OMAHA.

&&

LAT...LON 4196 9600 4208 9619 4213 9616 4214 9591
      4201 9585
TIME...MOT...LOC 2348Z 256DEG 21KT 4209 9612

$$

NIETFELD

317 
WWUS53 KOAX 100001
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
701 PM CDT SAT APR 9 2011

IAC133-100030-
/O.CON.KOAX.TO.W.0009.000000T0000Z-110410T0030Z/
MONONA IA-
701 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL MONONA COUNTY
UNTIL 730 PM CDT...

AT 657 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS
DANGEROUS STORM WAS LOCATED 6 MILES EAST OF WHITING...OR 32 MILES
SOUTHEAST OF SIOUX CITY...MOVING EAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
  CASTANA.

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.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN OMAHA.

&&

LAT...LON 4203 9586 4204 9603 4210 9608 4213 9607
      4214 9591
TIME...MOT...LOC 0001Z 255DEG 23KT 4213 9600

$$

NIETFELD

009 
WWUS53 KOAX 100004
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
704 PM CDT SAT APR 9 2011

IAC133-100030-
/O.CON.KOAX.TO.W.0009.000000T0000Z-110410T0030Z/
MONONA IA-
704 PM CDT SAT APR 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL MONONA COUNTY
UNTIL 730 PM CDT...

AT 702 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS
DANGEROUS STORM WAS LOCATED 8 MILES EAST OF WHITING...OR 33 MILES
SOUTHEAST OF SIOUX CITY...MOVING EAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
  MAINLY RURAL AREAS OF CENTRAL MONONA COUNTY.

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.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN OMAHA.

&&

LAT...LON 4207 9588 4210 9601 4211 9603 4213 9604
      4214 9591
TIME...MOT...LOC 0004Z 258DEG 24KT 4214 9597

$$

NIETFELD

587 
WWUS53 KOAX 100014
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
714 PM CDT SAT APR 9 2011

IAC133-100023-
/O.CAN.KOAX.TO.W.0009.000000T0000Z-110410T0030Z/
MONONA IA-
714 PM CDT SAT APR 9 2011

...THE TORNADO WARNING FOR CENTRAL MONONA COUNTY IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED 
AREA.  HOWEVER...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHEAST 
MONONA COUNTY UNTIL 745 PM.  

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT 
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE 
IN OMAHA.

LAT...LON 4207 9588 4210 9601 4211 9603 4213 9604
      4214 9591
TIME...MOT...LOC 0013Z 258DEG 24KT 4215 9589

$$

NIETFELD

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 9, 6:16 PM CDT	Severe Thunderstorm Warning	OAX	Monona	14 min
Apr 9, 6:33 PM CDT	Severe Thunderstorm Warning	OAX	Monona	27 min
Apr 9, 6:55 PM CDT	Severe Thunderstorm Warning	OAX	Monona	17 min

Nearby

Tornado Warnings in Iowa, 2011 Every tornado warning in 2011 Tornadoes 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.