Alert archive / Iowa / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 66, NWS Sioux Falls, SD

May 12, 2011Ida County, Woodbury County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at May 12, 2011, 5:45 PM CDT for Ida County, Woodbury County, Iowa. It was in force for 45 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: May 12, 2011, 5:45 PM CDT (22:45 UTC)
Expired: May 12, 2011, 6:30 PM CDT
In force: 45 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Hail: 1.0 in
Wind: 58.0 mph

Counties Ida County, IA, Woodbury County, IA

The radar

The Omaha radar (KOAX), 132 km from the middle of the area, began a volume at 22:44 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
May 12, 6:00 PM CDT	HAIL 1.5	4 Sw Holstein, IA

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

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.8 hours before the alert went out and 132 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: 353 J/kg
Mixed-layer CIN: -73 J/kg
Mixed-layer LCL: 759 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 82 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

727 
WUUS53 KFSD 122245
SVRFSD
IAC093-193-122330-
/O.NEW.KFSD.SV.W.0066.110512T2245Z-110512T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
545 PM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  IDA COUNTY IN NORTHWEST IOWA...
  EASTERN WOODBURY COUNTY IN NORTHWEST IOWA...

* UNTIL 630 PM CDT

* AT 543 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE       
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZED  
  HAIL. THIS STORM WAS LOCATED NEAR BATTLE CREEK...OR 10 MILES WEST  
  OF IDA GROVE...AND MOVING NORTHEAST AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  IDA GROVE AROUND 610 PM CDT...
  HOLSTEIN AROUND 630 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS EXHIBITED SOME WEAK ROTATION. TORNADOES CAN DEVELOP
QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH ONE IS NOT IMMEDIATELY
LIKELY...IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF
SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL
INTERIOR ROOM.

&&

LAT...LON 4230 9585 4256 9576 4256 9550 4253 9545
      4241 9543 4221 9544 4220 9546 4220 9577
TIME...MOT...LOC 2243Z 206DEG 9KT 4235 9567
WIND...HAIL <58MPH <1.00IN

$$

LIEBL

1 follow-up statement

131 
WWUS53 KFSD 122256
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
556 PM CDT THU MAY 12 2011

IAC093-193-122330-
/O.CON.KFSD.SV.W.0066.000000T0000Z-110512T2330Z/
WOODBURY IA-IDA IA-
556 PM CDT THU MAY 12 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR IDA AND
EASTERN WOODBURY COUNTIES UNTIL 630 PM CDT...

AT 556 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING GOLF BALL SIZE HAIL.  THIS
STORM WAS LOCATED NEAR BATTLE CREEK...OR 9 MILES WEST OF IDA GROVE...
MOVING NORTHEAST AT 10 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  IDA GROVE AROUND 615 PM CDT...
  HOLSTEIN AROUND 630 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS EXHIBITED SOME WEAK ROTATION. TORNADOES CAN DEVELOP
QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH ONE IS NOT IMMEDIATELY
LIKELY...IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF
SAFETY INSIDE A STURDY STRUCTURE... SUCH AS A BASEMENT OR SMALL
INTERIOR ROOM.

&&

LAT...LON 4230 9585 4256 9576 4256 9550 4253 9545
      4241 9543 4221 9544 4220 9546 4220 9577
TIME...MOT...LOC 2256Z 208DEG 8KT 4237 9565
WIND...HAIL <58MPH 1.75IN

$$

LIEBL

The office that day

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

Issued	Product	Office	Counties	Lasted
May 11, 7:07 PM CDT	Severe Thunderstorm Warning	FSD	Lyon, Osceola	23 min
May 11, 7:27 PM CDT	Severe Thunderstorm Warning	FSD	Osceola	33 min
May 12, 5:21 PM CDT	Severe Thunderstorm Warning	FSD	Ida, Woodbury	24 min
May 12, 5:53 PM CDT	Severe Thunderstorm Warning	FSD	Woodbury	52 min
May 12, 6:28 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Ida, Woodbury	47 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.