Alert archive / Wyoming / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 4, NWS Cheyenne, WY

May 9, 2011Goshen County, Niobrara County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at May 9, 2011, 5:43 PM MDT for Goshen County, Niobrara County, Wyoming. It was in force for 43 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 9, 2011, 5:43 PM MDT (23:43 UTC)
Expired: May 9, 2011, 6:26 PM MDT
In force: 43 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.5 in
Wind: 60.0 mph

Counties Goshen County, WY, Niobrara County, WY

The radar

The Cheyenne radar (KCYS), 175 km from the middle of the area, began a volume at 23:43 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, 5:45 PM MDT	HAIL 1	Manville, WY

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 12:00Z, 11.7 hours before the alert went out and 201 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: 90 J/kg
Mixed-layer CIN: -588 J/kg
Mixed-layer LCL: 782 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 108 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.

259 
WUUS55 KCYS 092343
SVRCYS
WYC015-027-100030-
/O.NEW.KCYS.SV.W.0004.110509T2343Z-110510T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
543 PM MDT MON MAY 9 2011

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN GOSHEN COUNTY IN SOUTHEAST WYOMING...
  SOUTHERN NIOBRARA COUNTY IN EAST CENTRAL WYOMING...

* UNTIL 630 PM MDT

* AT 539 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING PING PONG BALL
  SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS
  WERE LOCATED ALONG A LINE EXTENDING FROM 7 MILES SOUTH OF MANNING
  RANCH TO LUSK TO 6 MILES SOUTH OF JAY EM...AND MOVING NORTHEAST AT
  25 MPH.

* LOCATIONS IMPACTED INCLUDE...
  LUSK AND LANCE CREEK.

THIS REPLACES THE PREVIOUSLY ISSUED WARNING.  A SEVERE THUNDERSTORM
WATCH REMAINS IN EFFECT UNTIL 9 PM. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

IF YOU ARE IN THE PATH OF THESE STORMS...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 4283 10405 4228 10434 4258 10466 4261 10466
      4261 10470 4278 10489 4321 10488
TIME...MOT...LOC 2342Z 246DEG 20KT 4289 10485 4270 10445
          4239 10430
WIND...HAIL 60MPH 1.50IN

$$

2 follow-up statements

640 
WWUS55 KCYS 100006
SVSCYS

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

WYC015-027-100030-
/O.CON.KCYS.SV.W.0004.000000T0000Z-110510T0030Z/
NIOBRARA WY-GOSHEN WY-
606 PM MDT MON MAY 9 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHEASTERN
GOSHEN AND SOUTHERN NIOBRARA COUNTIES UNTIL 630 PM MDT...

AT 604 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING PING PONG BALL SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
LOCATED ALONG A LINE EXTENDING FROM 6 MILES SOUTHWEST OF LANCE CREEK
TO 8 MILES EAST OF LUSK TO 6 MILES SOUTHEAST OF PRAIRIE CENTER...
MOVING TO THE NORTHEAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE...
  LANCE CREEK.

AT 545 PM...ONE INCH DIAMETER HAIL WAS REPORTED IN MANVILLE.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

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 4321 10488 4283 10406 4247 10426 4258 10446
      4261 10470 4285 10480
TIME...MOT...LOC 0005Z 246DEG 20KT 4294 10469 4275 10429
          4244 10414
WIND...HAIL 60MPH 1.50IN

$$

MSW

938 
WWUS55 KCYS 100026
SVSCYS

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

WYC015-027-100035-
/O.CAN.KCYS.SV.W.0004.000000T0000Z-110510T0030Z/
NIOBRARA WY-GOSHEN WY-
626 PM MDT MON MAY 9 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN GOSHEN AND
SOUTHERN NIOBRARA COUNTIES IS CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAS WEAKENED BELOW
SEVERE LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR
PROPERTY.  HOWEVER SMALL HAIL...WIND GUSTS TO 50 MPH AND HEAVY RAIN 
ARE STILL POSSIBLE WITH THESE THUNDERSTORMS.

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

LAT...LON 4321 10488 4283 10406 4247 10426 4258 10446
      4261 10470 4285 10480
TIME...MOT...LOC 0025Z 246DEG 20KT 4299 10455 4279 10415
          4248 10400

$$

MSW

The office that day

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

Issued	Product	Office	Counties	Lasted
May 9, 4:23 PM MDT	Severe Thunderstorm Warning	CYS	Platte	37 min
May 9, 4:57 PM MDT	Severe Thunderstorm Warning	CYS	Converse, Goshen, Niobrara, Platte	48 min
May 9, 4:59 PM MDT	Severe Thunderstorm Warning	CYS	Converse, Goshen, Niobrara, Platte	46 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 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.