Alert archive / Iowa / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 201, NWS Sioux Falls, SD

August 23, 2012Lyon County, Iowa; Rock County, Minnesota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 23, 2012, 7:45 PM CDT for Lyon County, Iowa; Rock County, Minnesota. It was in force for 45 min. 5 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: Aug 23, 2012, 7:45 PM CDT (00:45 UTC)
Expired: Aug 23, 2012, 8:30 PM CDT
In force: 45 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Lyon County, IA, Rock County, MN

The radar

The Sioux Falls radar (KFSD), 50 km from the middle of the area, began a volume at 00:44 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 23, 8:15 PM CDT	TSTM WND DMG	Ene Hills, MN	TREE DAMAGE INCLUDING 3 LARGE TREES BLOWN DOWN
Aug 23, 8:15 PM CDT	HAIL 0.75	Hills, MN	PEA TO DIME SIZE HAIL PAST TEN MINUTES
Aug 23, 8:15 PM CDT	HAIL 1	1 Nw Steen, MN
Aug 23, 8:18 PM CDT	TSTM WND DMG	E Hills, MN	3 INCH DIAMETER TREE BRANCHES DOWN
Aug 23, 8:18 PM CDT	HAIL 1.25	E Hills, MN

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 0.8 hours before the alert went out and 240 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: 190 J/kg
Mixed-layer CIN: -124 J/kg
Mixed-layer LCL: 2452 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 73 m²/s²
0-3 km storm-relative helicity: 169 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

183 
WUUS53 KFSD 240045
SVRFSD
IAC119-MNC133-240130-
/O.NEW.KFSD.SV.W.0201.120824T0045Z-120824T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
745 PM CDT THU AUG 23 2012

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN LYON COUNTY IN NORTHWEST IOWA...
  SOUTHERN ROCK COUNTY IN SOUTHWEST MINNESOTA...

* UNTIL 830 PM CDT

* AT 744 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS
  LOCATED 6 MILES EAST OF HILLS...OR 7 MILES SOUTH OF LUVERNE...AND
  MOVING SOUTHEAST AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  STEEN AROUND 750 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE
HAIL AND DAMAGING WINDS. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 4339 9609 4353 9644 4363 9625 4353 9605
      4350 9605 4350 9600 4349 9598
TIME...MOT...LOC 0044Z 293DEG 11KT 4355 9623
WIND...HAIL 60MPH 1.00IN

$$

CHAPMAN

3 follow-up statements

368 
WWUS53 KFSD 240110
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
810 PM CDT THU AUG 23 2012

IAC119-MNC133-240130-
/O.CON.KFSD.SV.W.0201.000000T0000Z-120824T0130Z/
LYON IA-ROCK MN-
810 PM CDT THU AUG 23 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHERN ROCK 
AND NORTHERN LYON COUNTIES UNTIL 830 PM CDT...

AT 810 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
HILLS...OR 9 MILES NORTHWEST OF ROCK RAPIDS...MOVING SOUTHEAST AT 10
MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  ROCK RAPIDS AROUND 830 PM CDT...

OTHER LOCATIONS IMPACTED BY THIS SEVERE THUNDERSTORM INCLUDE STEEN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PREPARE IMMEDIATELY FOR LARGE HAIL AND DAMAGING WINDS IF YOU ARE IN
THE PATH OF THIS STORM. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 4348 9605 4339 9609 4353 9644 4360 9623
      4353 9605
TIME...MOT...LOC 0110Z 309DEG 9KT 4352 9626
WIND...HAIL 60MPH 1.00IN

$$

CHAPMAN

272 
WWUS53 KFSD 240124
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
824 PM CDT THU AUG 23 2012

IAC119-MNC133-240130-
/O.CON.KFSD.SV.W.0201.000000T0000Z-120824T0130Z/
LYON IA-ROCK MN-
824 PM CDT THU AUG 23 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHERN ROCK 
AND NORTHERN LYON COUNTIES UNTIL 830 PM CDT...

AT 823 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
HILLS...OR 11 MILES NORTHWEST OF ROCK RAPIDS...MOVING EAST AT 10 MPH.

THIS SEVERE THUNDERSTORM WILL AFFECT MAINLY RURAL AREAS OF NORTH
CENTRAL LYON AND SOUTHERN ROCK COUNTIES...INCLUDING THE FOLLOWING
LOCATIONS STEEN.

AT 818 PM CDT...A TRAINED WEATHER SPOTTER REPORTED SEVERAL 3 INCH
TREE BRANCHES DOWN AND HALF DOLLAR SIZE HAIL IN HILLS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PREPARE IMMEDIATELY FOR LARGE HAIL AND DAMAGING WINDS IF YOU ARE IN
THE PATH OF THIS STORM. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 4348 9605 4339 9609 4353 9644 4360 9623
      4353 9605
TIME...MOT...LOC 0123Z 290DEG 7KT 4352 9634
WIND...HAIL 60MPH 1.00IN

$$
CHAPMAN

596 
WWUS53 KFSD 240131
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
831 PM CDT THU AUG 23 2012

IAC119-MNC133-240141-
/O.EXP.KFSD.SV.W.0201.000000T0000Z-120824T0130Z/
LYON IA-ROCK MN-
831 PM CDT THU AUG 23 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN ROCK AND NORTHERN 
LYON 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 HAIL TO NICKEL SIZE...WIND GUSTS TO 50 MPH...AND 
HEAVY RAIN ARE STILL POSSIBLE WITH THIS THUNDERSTORM.

LAT...LON 4348 9605 4339 9609 4353 9644 4360 9623
      4353 9605
TIME...MOT...LOC 0124Z 290DEG 7KT 4352 9634

$$

CHAPMAN

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 23, 7:01 PM CDT	Severe Thunderstorm Warning	FSD	Nobles, Rock	44 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2012 Severe Thunderstorm Warnings in Minnesota, 2012 Every severe thunderstorm warning in 2012

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.