Alert archive / Iowa / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 49, NWS Des Moines, IA

May 11, 20116 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 11, 2011, 5:44 PM CDT for 6 counties in Iowa. It was in force for 46 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: May 11, 2011, 5:44 PM CDT (22:44 UTC)
Expired: May 11, 2011, 6:30 PM CDT
In force: 46 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Clarke County, IA, Decatur County, IA, Lucas County, IA, Madison County, IA, Ringgold County, IA, Warren County, IA

The radar

The Des Moines radar (KDMX), 99 km from the middle of the area, began a volume at 22:47 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
May 11, 6:04 PM CDT	TSTM WND GST 60	Ene Kellerton, IA	OBSERVER REPORTED WIND GUSTS AT LEAST 60 MPH HEAVY RAIN BLOWING HORIZONTALLY.
May 11, 6:08 PM CDT	TSTM WND GST 60	5 Nne Grand River, IA	SPOTTER REPORTED AT LEAST 60 MPH WIND. WIND BLOWING RAIN HORIZONTALLY AND STRONGLY SHOOK THEIR VEHICLE.

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
May 11, 2:53 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.7 hours before the alert went out and 209 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: 909 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 1123 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 177 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.2

Open this sounding in Storm Lab

The text

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

819 
WUUS53 KDMX 112244
SVRDMX
IAC039-053-117-121-159-181-112330-
/O.NEW.KDMX.SV.W.0049.110511T2244Z-110511T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
544 PM CDT WED MAY 11 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CLARKE COUNTY IN SOUTH CENTRAL IOWA...
  WESTERN DECATUR COUNTY IN SOUTH CENTRAL IOWA...
  NORTHWESTERN LUCAS COUNTY IN SOUTH CENTRAL IOWA...
  SOUTHEASTERN MADISON COUNTY IN SOUTH CENTRAL IOWA...
  EASTERN RINGGOLD COUNTY IN SOUTH CENTRAL IOWA...
  SOUTHERN WARREN COUNTY IN SOUTH CENTRAL IOWA...

* UNTIL 630 PM CDT

* AT 542 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 NEAR
  LAMONI...AND MOVING NORTHEAST AT 75 MPH.

* LOCATIONS IMPACTED INCLUDE...
  OSCEOLA...BEACONSFIELD...DECATUR CITY...GRAND RIVER...VAN WERT...
  WELDON...MURRAY...WOODBURN...TRURO...NEW VIRGINIA...ST. CHARLES...
  ST. MARYS AND LACONA.

THIS INCLUDES INTERSTATE 35 BETWEEN MILE MARKERS 3 AND 54.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO AN INTERIOR ROOM AND STAY AWAY FROM WINDOWS. IF YOU ARE IN A
MOBILE HOME...GET OUT NOW...AND SEEK SHELTER IN A REINFORCED
BUILDING.

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. SEVERE
THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO WARNING. IF A
TORNADO IS SPOTTED...IMMEDIATELY MOVE TO THE BASEMENT OR SMALL
INTERIOR ROOM OF A REINFORCED BUILDING.

&&

LAT...LON 4061 9417 4090 9405 4090 9402 4097 9402
      4135 9386 4121 9333 4057 9393 4057 9404
TIME...MOT...LOC 2244Z 205DEG 63KT 4070 9398
WIND...HAIL 60MPH 1.00IN

$$

BOKSA

2 follow-up statements

467 
WWUS53 KDMX 112317
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
617 PM CDT WED MAY 11 2011

IAC039-053-117-121-159-181-112330-
/O.CON.KDMX.SV.W.0049.000000T0000Z-110511T2330Z/
WARREN IA-RINGGOLD IA-MADISON IA-LUCAS IA-CLARKE IA-DECATUR IA-
617 PM CDT WED MAY 11 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHWESTERN
DECATUR...CLARKE...NORTHWESTERN LUCAS...SOUTHEASTERN MADISON...
NORTHEASTERN RINGGOLD AND SOUTHERN WARREN COUNTIES UNTIL 630 PM
CDT...

AT 612 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A SEVERE
THUNDERSTORM PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS
STORM WAS LOCATED 11 MILES NORTHWEST OF LEON...OR 18 MILES NORTH OF
LAMONI...MOVING NORTHEAST AT 40 MPH.

IN ADDITION...AT 608 PM CDT, DAMAGING WINDS OF AT LEAST 60 MPH WAS 
REPORTED FROM A SPOTTER IN NORTHWEST DECATUR COUNTY WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
  OSCEOLA...WELDON...MURRAY...WOODBURN...NEW VIRGINIA...TRURO...ST.
  CHARLES...ST. MARYS AND LACONA.

THIS INCLUDES INTERSTATE 35 BETWEEN MILE MARKERS 15 AND 54.

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.

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED... IMMEDIATELY MOVE TO THE BASEMENT OR SMALL INTERIOR ROOM
OF A REINFORCED BUILDING.

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

&&

LAT...LON 4080 9392 4083 9407 4090 9405 4090 9402
      4097 9402 4135 9386 4121 9333 4074 9377
      4073 9378
TIME...MOT...LOC 2316Z 204DEG 36KT 4091 9385
WIND...HAIL 60MPH <.75IN

$$

BOKSA

285 
WWUS53 KDMX 112333
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
633 PM CDT WED MAY 11 2011

IAC039-053-117-121-159-181-112342-
/O.EXP.KDMX.SV.W.0049.000000T0000Z-110511T2330Z/
WARREN IA-RINGGOLD IA-MADISON IA-LUCAS IA-CLARKE IA-DECATUR IA-
633 PM CDT WED MAY 11 2011

THIS INCLUDES INTERSTATE 35 BETWEEN MILE MARKERS 15 AND 54.

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN DECATUR...
CLARKE...NORTHWESTERN LUCAS...SOUTHEASTERN MADISON...NORTHEASTERN
RINGGOLD AND SOUTHERN WARREN COUNTIES HAS EXPIRED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
HOWEVER...ADDITIONAL STORMS WITH STRONG WIND GUSTS CAN BE EXPECTED 
THROUGH 730 PM.

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

LAT...LON 4080 9392 4083 9407 4090 9405 4090 9402
      4097 9402 4135 9386 4121 9333 4074 9377
      4073 9378
TIME...MOT...LOC 2317Z 204DEG 36KT 4092 9384

$$

BOKSA

The office that day

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

Issued	Product	Office	Counties	Lasted
May 11, 12:43 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Cass	47 min
May 11, 2:05 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Taylor	55 min
May 11, 2:22 PM CDT	Tornado Warning	DMX	Adams	23 min
May 11, 2:43 PM CDT	Flash Flood Warning	DMX	Adams, Taylor	6 hr
May 11, 2:51 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Taylor	39 min
May 11, 4:01 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Taylor	44 min
May 11, 4:11 PM CDT	Tornado Warning	DMX	Adams, Taylor	49 min
May 11, 4:42 PM CDT	Flash Flood Warning	DMX	Adams, Taylor	6 hr
May 11, 4:50 PM CDT	Tornado Warning	DMX	Adams, Union	40 min
May 11, 4:57 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Taylor	38 min
May 11, 5:32 PM CDT	Severe Thunderstorm Warning	DMX	Adams, Ringgold, Taylor, Union	43 min
May 11, 5:42 PM CDT	Tornado Warning	DMX	Union	33 min
May 11, 6:03 PM CDT	Flash Flood Warning	DMX	Union	6 hr
May 11, 6:06 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Clarke, Madison, Union	54 min
May 11, 6:37 PM CDT	Severe Thunderstorm Warning	DMX	Dallas, Madison, Polk, Warren	53 min
May 11, 6:42 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Lucas, Warren	48 min
May 11, 6:46 PM CDT	Severe Thunderstorm Warning	DMX	Wayne	44 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.