Alert archive / Iowa / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 271, NWS Des Moines, IA

August 6, 2011Adair County, Guthrie County, Madison County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 6, 2011, 9:58 PM CDT for Adair County, Guthrie County, Madison County, Iowa. It was in force for 47 min. 1 report 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: Aug 6, 2011, 9:58 PM CDT (02:58 UTC)
Expired: Aug 6, 2011, 10:45 PM CDT
In force: 47 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Adair County, IA, Guthrie County, IA, Madison County, IA

The radar

The Des Moines radar (KDMX), 58 km from the middle of the area, began a volume at 03:01 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
Aug 6, 10:33 PM CDT	TSTM WND DMG	Macksburg, IA	ROOF DAMAGE TO AMERICAN LEGION BUILDING. TIME ESTIMATED.

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
Aug 6, 5:32 PM CDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 3.0 hours before the alert went out and 176 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: 3454 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 1012 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 110 m²/s²
Significant tornado parameter: 1.9
Supercell composite: 13.5

Open this sounding in Storm Lab

The text

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

675 
WUUS53 KDMX 070258
SVRDMX
IAC001-077-121-070345-
/O.NEW.KDMX.SV.W.0271.110807T0258Z-110807T0345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
958 PM CDT SAT AUG 6 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN ADAIR COUNTY IN SOUTHWEST IOWA...
  SOUTHEASTERN GUTHRIE COUNTY IN WEST CENTRAL IOWA...
  MADISON COUNTY IN SOUTH CENTRAL IOWA...

* UNTIL 1045 PM CDT

* AT 956 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 8 MILES
  SOUTHWEST OF STUART...OR 27 MILES NORTH OF CRESTON...AND MOVING
  SOUTHEAST AT 35 MPH.

* LOCATIONS IMPACTED INCLUDE...
  GREENFIELD...STUART...EARLHAM...WINTERSET...MACKSBURG...PATTERSON
  AND EAST PERU.

THIS INCLUDES INTERSTATE 80 BETWEEN MILE MARKERS 80 AND 99.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO AN INTERIOR ROOM AND STAY AWAY FROM WINDOWS.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS. TURN AROUND DON/T DROWN.

&&

LAT...LON 4137 9468 4161 9447 4154 9424 4150 9424
      4150 9413 4140 9379 4115 9395 4116 9422
TIME...MOT...LOC 0258Z 298DEG 32KT 4143 9443
WIND...HAIL 60MPH 1.00IN

$$

AW

1 follow-up statement

337 
WWUS53 KDMX 070334
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1034 PM CDT SAT AUG 6 2011

IAC077-070344-
/O.CAN.KDMX.SV.W.0271.000000T0000Z-110807T0345Z/
GUTHRIE IA-
1034 PM CDT SAT AUG 6 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN GUTHRIE COUNTY IS
CANCELLED...

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

LAT...LON 4116 9422 4130 9453 4150 9438 4150 9413
      4140 9379 4115 9395
TIME...MOT...LOC 0334Z 298DEG 32KT 4131 9415

$$

IAC001-121-070345-
/O.CON.KDMX.SV.W.0271.000000T0000Z-110807T0345Z/
MADISON IA-ADAIR IA-
1034 PM CDT SAT AUG 6 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR EASTERN ADAIR
AND MADISON COUNTIES UNTIL 1045 PM CDT...

AT 1033 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 7 MILES
WEST OF WINTERSET...OR 21 MILES NORTHEAST OF CRESTON...MOVING
SOUTHEAST AT 35 MPH.

LOCATIONS IMPACTED INCLUDE...
  WINTERSET...MACKSBURG...EAST PERU AND PATTERSON.

THIS INCLUDES INTERSTATE 80 BETWEEN MILE MARKERS 89 AND 98.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PREPARE FOR DAMAGING WINDS...FALLING TREES AND FLYING DEBRIS. MOVE
INDOORS AND STAY AWAY FROM WINDOWS. IF YOU ARE IN A MOBILE HOME...GET
OUT NOW...AND SEEK SHELTER IN A REINFORCED BUILDING.

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCED
WARNING. IF A TORNADO IS SPOTTED...IMMEDIATELY MOVE TO THE BASEMENT
OR SMALL INTERIOR ROOM OF A REINFORCED BUILDING.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS. TURN AROUND DON/T DROWN.

&&

LAT...LON 4116 9422 4130 9453 4150 9438 4150 9413
      4140 9379 4115 9395
TIME...MOT...LOC 0334Z 298DEG 32KT 4131 9415
WIND...HAIL 60MPH 1.00IN

$$

AW

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 6, 7:34 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	26 min
Aug 6, 7:57 PM CDT	Severe Thunderstorm Warning	DMX	Audubon, Carroll, Crawford	48 min
Aug 6, 8:32 PM CDT	Severe Thunderstorm Warning	DMX	Audubon, Cass, Guthrie	43 min
Aug 6, 9:08 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Audubon, Cass, Guthrie	52 min
Aug 6, 9:26 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Cass, Ringgold, Taylor, Union	49 min
Aug 6, 9:41 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Audubon, Cass	49 min
Aug 6, 10:16 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Adams, Madison, Ringgold, Taylor, Union	44 min
Aug 6, 10:30 PM CDT	Tornado Warning	DMX	Adair, Madison	28 min
Aug 6, 10:45 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur	45 min
Aug 6, 10:46 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Madison, Warren	29 min
Aug 6, 11:08 PM CDT	Severe Thunderstorm Warning	DMX	Lucas, Wayne	52 min
Aug 6, 11:09 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Jasper, Lucas, Madison, Marion, Polk and 1 more	51 min
Aug 6, 11:32 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Monroe	43 min
Aug 6, 11:36 PM CDT	Tornado Warning	DMX	Lucas, Marion, Monroe	24 min
Aug 6, 11:48 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Marion, Poweshiek	57 min
Aug 7, 12:02 AM CDT	Severe Thunderstorm Warning	DMX	Davis, Wapello	58 min
Aug 7, 3:19 AM CDT	Severe Thunderstorm Warning	DMX	Butler, Franklin	41 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2011 Every severe thunderstorm warning 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.