Alert archive / Nebraska / Tornado Warnings in 2011

Tornado Warning 6, NWS Cheyenne, WY

May 9, 2011Box Butte County, Dawes County, Nebraska

NWS Cheyenne, WY issued this tornado warning at May 9, 2011, 8:17 PM MDT for Box Butte County, Dawes County, Nebraska. It was in force for 30 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 9, 2011, 8:17 PM MDT (02:17 UTC)
Expired: May 9, 2011, 8:47 PM MDT
In force: 30 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon

Counties Box Butte County, NE, Dawes County, NE

The radar

The Rapid City radar (KUDX), 161 km from the middle of the area, began a volume at 02:17 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 9, 8:22 PM MDT	HAIL 2.75	15 S Chadron, NE
May 9, 8:46 PM MDT	HAIL 0.75	5 W Hay Springs, NE	MARBLE SIZE HAIL HEAVY RAIN AND LOW VISIBILITY REPORTED ALONG COUNTY LINE WEST OF HAY SPRINGS.

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 9, 2:26 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 2.3 hours before the alert went out and 155 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: 231 J/kg
Mixed-layer CIN: -129 J/kg
Mixed-layer LCL: 581 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 114 m²/s²
0-3 km storm-relative helicity: 247 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

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

451 
WFUS55 KCYS 100217
TORCYS
NEC013-045-100300-
/O.NEW.KCYS.TO.W.0006.110510T0217Z-110510T0300Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
817 PM MDT MON MAY 9 2011

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* TORNADO WARNING FOR...
  NORTH CENTRAL BOX BUTTE COUNTY IN THE PANHANDLE OF NEBRASKA...
  DAWES COUNTY IN THE PANHANDLE OF NEBRASKA...

* UNTIL 900 PM MDT

* AT 811 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING A TORNADO. THESE
  DANGEROUS STORMS WERE LOCATED ALONG A LINE EXTENDING FROM CRAWFORD
  TO 6 MILES EAST OF BOX BUTTE DAM...AND MOVING TO THE NORTHEAST AT
  35 MPH. 

* LOCATIONS IMPACTED INCLUDE...
  BOX BUTTE DAM
  CHADRON.

THIS TORNADO WARNING REPLACES THE PREVIOUS TORNADO WARNING FOR 
NORTHWEST BOX BUTTE...SOUTHWEST DAWES AND EAST CENTRAL DAWES COUNTIES. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4237 10296 4265 10344 4301 10333 4299 10278
      4280 10278 4275 10276 4250 10276
TIME...MOT...LOC 0215Z 336DEG 34KT 4265 10330 4241 10294

$$

MSW

2 follow-up statements

764 
WWUS55 KCYS 100234
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
834 PM MDT MON MAY 9 2011

NEC013-100243-
/O.CAN.KCYS.TO.W.0006.000000T0000Z-110510T0300Z/
BOX BUTTE NE-
834 PM MDT MON MAY 9 2011

...THE TORNADO WARNING FOR NORTH CENTRAL BOX BUTTE COUNTY IS
CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF
THE WARNED AREA.

LAT...LON 4244 10285 4276 10336 4301 10333 4299 10278
      4280 10278 4275 10276 4250 10276
TIME...MOT...LOC 0233Z 336DEG 34KT 4288 10315 4251 10277

$$

NEC045-100300-
/O.CON.KCYS.TO.W.0006.000000T0000Z-110510T0300Z/
DAWES NE-
834 PM MDT MON MAY 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHEASTERN DAWES COUNTY
UNTIL 900 PM MDT...

AT 827 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING A TORNADO.  THESE
DANGEROUS STORMS WERE LOCATED ALONG A LINE EXTENDING FROM 8 MILES
NORTHWEST OF CHADRON AIRPORT TO 10 MILES SOUTHWEST OF HAY SPRINGS...
MOVING TO THE NORTHEAST AT 40 MPH.

LOCATIONS IMPACTED INCLUDE...
  WHITNEY LAKE...WHITNEY...CHADRON STATE PARK AND CHADRON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4244 10285 4276 10336 4301 10333 4299 10278
      4280 10278 4275 10276 4250 10276
TIME...MOT...LOC 0233Z 336DEG 34KT 4288 10315 4251 10277

$$

MSW

719 
WWUS55 KCYS 100247
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
847 PM MDT MON MAY 9 2011

NEC045-100256-
/O.CAN.KCYS.TO.W.0006.000000T0000Z-110510T0300Z/
DAWES NE-
847 PM MDT MON MAY 9 2011

...THE TORNADO WARNING FOR NORTHEASTERN DAWES COUNTY IS CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAVE WEAKENED AND MOVED
EAST OF THE COUNTY AS OF 845 PM. FOR THAT REASON...THE TORNADO WARNING
WHICH WAS IN EFFECT UNTIL 9 PM FOR NORTHEAST DAWES COUNTY HAS BEEN
CANCELLED. STORMS PRODUCING HEAVY RAINFALL AND STRONG WIND GUSTS ARE
STILL POSSIBLE IN THE NORTHEAST CORNER OF THE COUNTY THROUGH 930 PM. 

LAT...LON 4244 10285 4276 10336 4301 10333 4299 10278
      4280 10278 4275 10276 4250 10276
TIME...MOT...LOC 0246Z 336DEG 34KT 4238 10314 4214 10278

$$

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 9, 6:03 PM MDT	Severe Thunderstorm Warning	CYS	Sioux	57 min
May 9, 6:55 PM MDT	Tornado Warning	CYS	Dawes, Sioux	35 min
May 9, 7:32 PM MDT	Tornado Warning	CYS	Dawes, Sioux	43 min
May 9, 7:53 PM MDT	Tornado Warning	CYS	Box Butte, Dawes, Sioux	28 min

Nearby

Tornado Warnings in Nebraska, 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.