Alert archive / Nebraska / Tornado Warnings in 2011

Tornado Warning 3, NWS Cheyenne, WY

May 9, 2011Dawes County, Sioux County, Nebraska

NWS Cheyenne, WY issued this tornado warning at May 9, 2011, 6:55 PM MDT for Dawes County, Sioux County, Nebraska. It was in force for 35 min. 6 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, 6:55 PM MDT (00:55 UTC)
Expired: May 9, 2011, 7:30 PM MDT
In force: 35 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon

Counties Dawes County, NE, Sioux County, NE

The radar

The Rapid City radar (KUDX), 146 km from the middle of the area, began a volume at 00:58 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, 7:10 PM MDT	FUNNEL CLOUD	5 E Whitney, NE	A FUNNEL CLOUD WAS REPORTED JUST NORTH OF HIGHWAY 20...4 TO 5 MILES EAST OF WHITNEY.
May 9, 7:10 PM MDT	TORNADO	10 E Harrison, NE	911 CALL FROM THE PUBLIC REPORTED A TORNADO ON THE GROUND 10 MILES EAST OF HARRISON
May 9, 7:11 PM MDT	HAIL 1	17 E Harrison, NE	HAIL FALLING AS WE SPOKE.
May 9, 7:18 PM MDT	HAIL 0.25	10 Nw Crawford, NE
May 9, 7:18 PM MDT	HAIL 0.25	Crawford, NE
May 9, 7:30 PM MDT	HAIL 1.75	11 N Crawford, NE

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, 0.9 hours before the alert went out and 139 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.

935 
WFUS55 KCYS 100055
TORCYS
NEC045-165-100130-
/O.NEW.KCYS.TO.W.0003.110510T0055Z-110510T0130Z/

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

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHERN DAWES COUNTY IN THE PANHANDLE OF NEBRASKA...
  NORTHEASTERN SIOUX COUNTY IN THE PANHANDLE OF NEBRASKA...

* UNTIL 730 PM MDT

* AT 650 PM MDT...DOPPLER RADAR INDICATED A POSSIBLE TORNADO 10 MILES
  EAST OF HARRISON...OR 36 MILES WEST OF CHADRON. DOPPLER RADAR SHOWED
  THE STORM PRODUCING THE POSSIBLE TORNADO MOVING NORTHEAST AT 30 MPH.

  AT 636 A BRIEF TORNADO WAS REPORTED BY TRAINED SPOTTERS 5 MILES EAST
  OF HARRISON.  

* LOCATIONS IMPACTED INCLUDE...
  CHADRON...CRAWFORD...WHITNEY LAKE...AGATE DAM RESERVOIR...CHADRON
  AIRPORT...FORT ROBINSON AND WHITNEY.

THIS WARNING REPLACES THE PREVIOUSLY ISSUED SEVERE THUNDERSTORM WARNING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF IN THE PATH OF THE TORNADIC STORM...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 4295 10278 4245 10362 4276 10387 4301 10363
      4300 10288
TIME...MOT...LOC 0052Z 216DEG 25KT 4273 10368

$$

MSW

2 follow-up statements

884 
WWUS55 KCYS 100112
SVSCYS

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

NEC045-165-100130-
/O.CON.KCYS.TO.W.0003.000000T0000Z-110510T0130Z/
DAWES NE-SIOUX NE-
712 PM MDT MON MAY 9 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHEASTERN SIOUX AND
NORTHERN DAWES COUNTIES UNTIL 730 PM MDT...

AT 707 PM MDT...THE PUBLIC REPORTED A TORNADO.  THIS TORNADO WAS
LOCATED 10 MILES EAST OF HARRISON...MOVING TO THE NORTHEAST AT 30 MPH. 

AT 710 PM...A TORNADO WAS REPORTED 10 MILES EAST OF HARRISON. 

LOCATIONS IMPACTED INCLUDE...
  WHITNEY LAKE...AGATE DAM RESERVOIR...CHADRON AIRPORT AND WHITNEY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A TORNADO IS ON THE GROUND. 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 4295 10278 4250 10357 4281 10371 4301 10363
      4300 10288
TIME...MOT...LOC 0110Z 216DEG 25KT 4283 10358

$$

MSW

773 
WWUS55 KCYS 100135
SVSCYS

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

NEC045-165-100144-
/O.EXP.KCYS.TO.W.0003.000000T0000Z-110510T0130Z/
DAWES NE-SIOUX NE-
735 PM MDT MON MAY 9 2011

...THE TORNADO WARNING FOR NORTHEASTERN SIOUX AND NORTHERN DAWES
COUNTIES IS BEING REISSUED...

PLEASE REFER TO THAT BULLETIN FOR THE LATEST SEVERE WEATHER
INFORMATION.  THE NEW TORNADO WARNING IS IN EFFECT UNTIL 815 PM FOR
NORTHERN DAWES AND NORTHEAST SIOUX COUNTIES.  THE SEVERE THUNDERSTORM
WILL ALSO PRODUCE LARGE HAIL...STRONG WIND GUSTS AND HEAVY RAIN. 

IN ADDITION...STRONG THUNDERSTORMS MAY REDEVELOP...AND A SEVERE
THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 9 PM. 

LAT...LON 4295 10278 4250 10357 4281 10371 4301 10363
      4300 10288
TIME...MOT...LOC 0112Z 216DEG 25KT 4284 10357

$$

MSW

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, 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
May 9, 8:17 PM MDT	Tornado Warning	CYS	Box Butte, Dawes	30 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.