Alert archive / Wyoming / Tornado Warnings in 2011

Tornado Warning 28, NWS Cheyenne, WY

July 12, 2011Laramie County, Wyoming

NWS Cheyenne, WY issued this tornado warning at Jul 12, 2011, 6:03 PM MDT for Laramie County, Wyoming. It was in force for 27 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: Jul 12, 2011, 6:03 PM MDT (00:03 UTC)
Expired: Jul 12, 2011, 6:30 PM MDT
In force: 27 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 24 km from the middle of the area, began a volume at 00:05 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
Jul 12, 6:34 PM MDT	HAIL 1	5 Sw Hillsdale, WY	JUST EAST OF MILE MARKER 375 ON INTERSTATE 80
Jul 12, 6:36 PM MDT	HAIL 2	6 Sw Hillsdale, WY

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

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 0.1 hours before the alert went out and 189 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: 596 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1449 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 256 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.2

Open this sounding in Storm Lab

The text

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

319 
WFUS55 KCYS 130003 RRA
TORCYS
WYC021-130030-
/O.NEW.KCYS.TO.W.0028.110713T0003Z-110713T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
603 PM MDT TUE JUL 12 2011

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL LARAMIE COUNTY IN SOUTHEAST WYOMING...

* UNTIL 630 PM MDT

* AT 601 PM MDT...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD 9
  MILES EAST OF CHEYENNE. A TORNADO MAY DEVELOP AT ANY TIME. DOPPLER
  RADAR SHOWED THIS DANGEROUS STORM MOVING NORTHEAST AT 20 MPH.

* LOCATIONS IMPACTED INCLUDE...
  HILLSDALE.

THIS INCLUDES INTERSTATE 80 IN WYOMING BETWEEN MILE MARKERS 372 AND
377.

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 4135 10452 4121 10441 4111 10460 4122 10469
TIME...MOT...LOC 0003Z 231DEG 15KT 4118 10461

$$

RE

2 follow-up statements

687 
WWUS55 KCYS 130018
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
618 PM MDT TUE JUL 12 2011

WYC021-130030-
/O.CON.KCYS.TO.W.0028.000000T0000Z-110713T0030Z/
LARAMIE WY-
618 PM MDT TUE JUL 12 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL LARAMIE COUNTY
UNTIL 630 PM MDT...

AT 615 PM MDT...TRAINED WEATHER SPOTTERS CONTINUE TO REPORT FUNNEL 
CLOUDS EAST OF CHEYENNE.  A TORNADO MAY DEVELOP AT ANY TIME. THIS
DANGEROUS STORM WAS LOCATED 10 MILES WEST OF BURNS...OR 13 MILES 
EAST OF CHEYENNE...MOVING NORTHEAST AT 15 MPH.

LOCATIONS IMPACTED INCLUDE...
  HILLSDALE.

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 4135 10452 4121 10441 4111 10460 4122 10469
TIME...MOT...LOC 0017Z 231DEG 15KT 4122 10455

$$

RE

230 
WWUS55 KCYS 130031
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
631 PM MDT TUE JUL 12 2011

WYC021-130041-
/O.EXP.KCYS.TO.W.0028.000000T0000Z-110713T0030Z/
LARAMIE WY-
631 PM MDT TUE JUL 12 2011

...THE TORNADO WARNING FOR CENTRAL LARAMIE COUNTY HAS EXPIRED...

THE TORNADO THREAT HAS DIMINISHED...THEREFORE THE TORNADO WARNING HAS
EXPIRED. HOWEVER...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT
FOR THE AREA.

LAT...LON 4135 10452 4121 10441 4111 10460 4122 10469
TIME...MOT...LOC 0018Z 231DEG 15KT 4122 10455

$$

RE

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 6:03 PM MDT	Tornado Warning	CYS	Goshen, Laramie, Platte	30 min
Jul 12, 6:56 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	45 min
Jul 12, 7:09 PM MDT	Flash Flood Warning	CYS	Goshen, Laramie	8 hr
Jul 12, 7:46 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	32 min
Jul 12, 10:26 PM MDT	Flash Flood Warning	CYS	Goshen, Laramie, Platte	4 hr

Nearby

Tornado Warnings in Wyoming, 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.