Alert archive / Iowa / Tornado Warnings in 2011

Tornado Warning 52, NWS Des Moines, IA

July 11, 2011Marshall County, Story County, Iowa

NWS Des Moines, IA issued this tornado warning at Jul 11, 2011, 3:53 AM CDT for Marshall County, Story County, Iowa. It was in force for 37 min. 6 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: Jul 11, 2011, 3:53 AM CDT (08:53 UTC)
Expired: Jul 11, 2011, 4:30 AM CDT
In force: 37 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon

Counties Marshall County, IA, Story County, IA

The radar

The Des Moines radar (KDMX), 65 km from the middle of the area, began a volume at 08:55 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

Time	Report	Where	Remark
Jul 11, 4:04 AM CDT	TSTM WND DMG	1 Sw Marshalltown, IA	POWER POLES SNAPPED IN HALF NEAR HIGHWAY 30...330 JUNCTION.
Jul 11, 4:05 AM CDT	TSTM WND DMG	S Marshalltown, IA	1 TO 2 MILES OF TOPPED TREES ALONG THE HAVERHILL BLACKTOP JUST SOUTH OF MARSHALLTOWN.
Jul 11, 4:09 AM CDT	TSTM WND DMG	Marshalltown, IA	EXTENSIVE DAMAGE REPORTED IN MARSHALLTOWN...TREES OVER ROADS...TREES ON HOMES...GAS LEAKS...POSSIBLE STRUCTURAL DAMAGE.
Jul 11, 4:13 AM CDT	TSTM WND DMG	1 W Le Grand, IA	SEMI BLOWN OVER ON HIGHWAY 30...NEAR LE GRAND
Jul 11, 4:20 AM CDT	TSTM WND GST 80	3 W Marshalltown, IA	MEASURED ON PERSONAL WEATHER STATION. DAMAGE NOTED INCLUDES FENCES DOWN...TREES SNAPPED...AND SIDING RIPPED FROM HOUSES.
Jul 11, 4:23 AM CDT	TSTM WND DMG	3 W Marshalltown Airpor, IA	NUMEROUS LARGE TREES DOWN WITH A COUPLE ON THE HOUSE. OUTBUILDING DAMAGE AT THE RESIDENCE AS WELL. A FUNNEL CLOUD WAS REPORTED NEAR TIME DAMAGE OCCURRED.

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.

Issued	Product	Office	Lasted
Jul 11, 1:21 AM CDT	Severe Thunderstorm Watch	SPC	4 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 8.9 hours before the alert went out and 217 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: 3733 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 850 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 165 m²/s²
Significant tornado parameter: 3.4
Supercell composite: 14.3

Open this sounding in Storm Lab

The text

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

758 
WFUS53 KDMX 110853
TORDMX
IAC127-169-110930-
/O.NEW.KDMX.TO.W.0052.110711T0853Z-110711T0930Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
353 AM CDT MON JUL 11 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* TORNADO WARNING FOR...
  MARSHALL COUNTY IN CENTRAL IOWA...
  SOUTHEASTERN STORY COUNTY IN CENTRAL IOWA...

* UNTIL 430 AM CDT

* AT 350 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
  STORM WAS LOCATED 6 MILES SOUTHWEST OF STATE CENTER...OR 19 MILES
  EAST OF AMES...AND MOVING NORTHEAST AT 45 MPH.

* LOCATIONS IMPACTED INCLUDE...
  MARSHALLTOWN...STATE CENTER...MELBOURNE...CLEMONS...ALBION...
  MARSHALLTOWN AIRPORT AND LE GRAND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IMMEDIATELY SEEK SHELTER IN A BASEMENT...
OR IN AN INTERIOR ROOM OF A REINFORCED BUILDING. STAY AWAY FROM
WINDOWS.

IF YOU ARE OUTSIDE...IN A MOBILE HOME...OR IN A VEHICLE...SEEK
SHELTER IN A NEARBY REINFORCED BUILDING. AS A LAST RESORT...FIND THE
LOWEST SPOT AVAILABLE AND COVER YOUR HEAD.

TORNADOES ARE DIFFICULT TO SEE AT NIGHT...ACT QUICKLY. TAKE COVER
NOW!

&&

LAT...LON 4188 9325 4205 9341 4221 9290 4221 9277
      4200 9277
TIME...MOT...LOC 0853Z 244DEG 41KT 4198 9323

$$

DONAVON

2 follow-up statements

351 
WWUS53 KDMX 110905
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
405 AM CDT MON JUL 11 2011

IAC127-169-110930-
/O.CON.KDMX.TO.W.0052.000000T0000Z-110711T0930Z/
STORY IA-MARSHALL IA-
405 AM CDT MON JUL 11 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR MARSHALL AND EAST CENTRAL
STORY COUNTIES UNTIL 430 AM CDT...

AT 400 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR STATE CENTER...OR 13 MILES WEST OF
MARSHALLTOWN...MOVING NORTHEAST AT 40 MPH.

LOCATIONS IMPACTED INCLUDE...
  MARSHALLTOWN...CLEMONS...ALBION...MARSHALLTOWN AIRPORT AND LE
  GRAND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IMMEDIATELY SEEK SHELTER IN A BASEMENT...
OR IN AN INTERIOR ROOM OF A REINFORCED BUILDING. STAY AWAY FROM
WINDOWS.

IF YOU ARE OUTSIDE...IN A MOBILE HOME...OR IN A VEHICLE...SEEK
SHELTER IN A NEARBY REINFORCED BUILDING. AS A LAST RESORT...FIND THE
LOWEST SPOT AVAILABLE AND COVER YOUR HEAD.

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

&&

LAT...LON 4190 9317 4207 9332 4221 9290 4221 9277
      4200 9277
TIME...MOT...LOC 0905Z 238DEG 35KT 4204 9311

$$

DONAVON

030 
WWUS53 KDMX 110921
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
421 AM CDT MON JUL 11 2011

IAC169-110931-
/O.CAN.KDMX.TO.W.0052.000000T0000Z-110711T0930Z/
STORY IA-
421 AM CDT MON JUL 11 2011

...THE TORNADO WARNING FOR EAST CENTRAL STORY COUNTY IS CANCELLED...

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

LAT...LON 4195 9297 4214 9310 4221 9290 4221 9277
      4200 9277
TIME...MOT...LOC 0921Z 248DEG 50KT 4212 9284

$$

IAC127-110930-
/O.CON.KDMX.TO.W.0052.000000T0000Z-110711T0930Z/
MARSHALL IA-
421 AM CDT MON JUL 11 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHEASTERN MARSHALL
COUNTY UNTIL 430 AM CDT...

AT 418 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR MARSHALLTOWN...MOVING EAST AT 60 MPH.

LOCATIONS IMPACTED INCLUDE...
  MAINLY RURAL AREAS OF NORTHEASTERN MARSHALL COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IMMEDIATELY SEEK SHELTER IN A BASEMENT...
OR IN AN INTERIOR ROOM OF A REINFORCED BUILDING. STAY AWAY FROM
WINDOWS.

IF YOU ARE OUTSIDE...IN A MOBILE HOME...OR IN A VEHICLE...SEEK
SHELTER IN A NEARBY REINFORCED BUILDING. AS A LAST RESORT...FIND THE
LOWEST SPOT AVAILABLE AND COVER YOUR HEAD.

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

&&

LAT...LON 4195 9297 4214 9310 4221 9290 4221 9277
      4200 9277
TIME...MOT...LOC 0921Z 248DEG 50KT 4212 9284

$$

DONAVON

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 11, 1:12 AM CDT	Severe Thunderstorm Warning	DMX	Emmet, Kossuth, Palo Alto	48 min
Jul 11, 2:10 AM CDT	Severe Thunderstorm Warning	DMX	Adair, Audubon, Cass, Guthrie	50 min
Jul 11, 2:24 AM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Hancock, Winnebago, Worth	51 min
Jul 11, 2:41 AM CDT	Severe Thunderstorm Warning	DMX	Adair, Dallas, Guthrie, Madison, Polk, Warren	49 min
Jul 11, 2:52 AM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Humboldt, Webster, Wright	38 min
Jul 11, 3:25 AM CDT	Severe Thunderstorm Warning	DMX	Boone, Marshall, Story	50 min
Jul 11, 3:34 AM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marion, Marshall, Polk, Story, Warren	41 min
Jul 11, 4:02 AM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marshall, Poweshiek, Tama	43 min
Jul 11, 4:18 AM CDT	Severe Thunderstorm Warning	DMX	Black Hawk, Tama	42 min
Jul 11, 4:32 AM CDT	Tornado Warning	DMX	Marshall, Tama	28 min
Jul 11, 4:57 AM CDT	Severe Thunderstorm Warning	DMX	Black Hawk	18 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.