Alert archive / Wyoming / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 77, NWS Cheyenne, WY

July 5, 2012Converse County, Niobrara County, Platte County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jul 5, 2012, 5:44 PM MDT for Converse County, Niobrara County, Platte County, Wyoming. It was in force for 46 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 5, 2012, 5:44 PM MDT (23:44 UTC)
Expired: Jul 5, 2012, 6:30 PM MDT
In force: 46 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 70.0 mph

Counties Converse County, WY, Niobrara County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 143 km from the middle of the area, began a volume at 23:44 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
Jul 5, 5:56 PM MDT	HAIL 0.5	Glendo, WY	PEA TO DIME SIZED HAIL. WIND GUSTS TO 35 MPH.
Jul 5, 6:03 PM MDT	HAIL 1	1 N Glendo, WY	LARGEST HAIL WAS QUARTER SIZED. THE MAJORITY WERE PEA SIZED.

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
Jul 5, 4:10 PM MDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 11.7 hours before the alert went out and 249 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1568 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

702 
WUUS55 KCYS 052344
SVRCYS
WYC009-027-031-060030-
/O.NEW.KCYS.SV.W.0077.120705T2344Z-120706T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
544 PM MDT THU JUL 5 2012

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN CONVERSE COUNTY IN EAST CENTRAL WYOMING...
  SOUTHWESTERN NIOBRARA COUNTY IN EAST CENTRAL WYOMING...
  NORTHERN PLATTE COUNTY IN SOUTHEAST WYOMING...

* UNTIL 630 PM MDT

* AT 540 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THIS STORM WAS LOCATED 6
  MILES SOUTHWEST OF SIBLEY PEAK...OR 24 MILES NORTH OF WHEATLAND...
  AND MOVING NORTHEAST AT 20 MPH.

* LOCATIONS IMPACTED INCLUDE...
  SIBLEY PEAK...GLENDO...GLENDO RESERVOIR AND TWO MOON CAMPGROUND.

THIS INCLUDES INTERSTATE 25 IN WYOMING BETWEEN MILE MARKERS 93 AND
118.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...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 4245 10465 4238 10465 4219 10513 4242 10529
      4243 10528 4245 10532 4271 10483
TIME...MOT...LOC 2344Z 234DEG 18KT 4239 10508
WIND...HAIL 70MPH 1.00IN

$$

MAZUR

2 follow-up statements

872 
WWUS55 KCYS 060002
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
602 PM MDT THU JUL 5 2012

WYC009-027-031-060030-
/O.CON.KCYS.SV.W.0077.000000T0000Z-120706T0030Z/
NIOBRARA WY-CONVERSE WY-PLATTE WY-
602 PM MDT THU JUL 5 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHEASTERN
PLATTE...EXTREME SOUTHEASTERN CONVERSE AND SOUTHWESTERN NIOBRARA
COUNTIES UNTIL 630 PM MDT...

AT 558 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THIS STORM WAS LOCATED NEAR
SIBLEY PEAK...OR 26 MILES NORTH OF WHEATLAND...MOVING NORTHEAST AT 20
MPH.

LOCATIONS IMPACTED INCLUDE...
  GLENDO...GLENDO RESERVOIR AND TWO MOON CAMPGROUND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AROUND 75 
MPH AND LARGE DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY 
STRUCTURE AND STAY AWAY FROM WINDOWS.

THIS IS AN EXTREMELY DANGEROUS SITUATION WITH VERY STRONG WIND 
SPEEDS EXPECTED. MOBILE HOMES AND HIGH PROFILE VEHICLES ARE 
ESPECIALLY SUSCEPTIBLE TO WINDS OF THIS MAGNITUDE AND MAY BE 
OVERTURNED. MOVE IMMEDIATELY TO A STURDY BUILDING AND STAY AWAY FROM 
WINDOWS.

&&

LAT...LON 4244 10465 4240 10465 4239 10465 4224 10500
      4252 10519 4271 10483
TIME...MOT...LOC 0000Z 234DEG 18KT 4244 10499
WIND...HAIL 80MPH 1.00IN

$$

MAZUR

533 
WWUS55 KCYS 060022
SVSCYS

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
622 PM MDT THU JUL 5 2012

WYC009-027-031-060030-
/O.EXP.KCYS.SV.W.0077.000000T0000Z-120706T0030Z/
NIOBRARA WY-CONVERSE WY-PLATTE WY-
622 PM MDT THU JUL 5 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN PLATTE COUNTY 
WILL EXPIRE AT 630 PM MDT...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED
AREA.  HOWEVER GUSTY WINDS AND HEAVY RAIN ARE STILL POSSIBLE WITH
THIS THUNDERSTORM.

LAT...LON 4244 10465 4240 10465 4239 10465 4224 10500
      4252 10519 4271 10483
TIME...MOT...LOC 0020Z 234DEG 18KT 4250 10488

$$

MAZUR

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 4, 8:43 PM MDT	Special Weather Statement	CYS	Albany	32 min
Jul 4, 8:52 PM MDT	Severe Thunderstorm Warning	CYS	Albany	20 min
Jul 4, 9:23 PM MDT	Special Weather Statement	CYS	Albany	37 min
Jul 5, 2:44 PM MDT	Special Weather Statement	CYS	Albany	31 min
Jul 5, 2:50 PM MDT	Special Weather Statement	CYS		25 min
Jul 5, 3:01 PM MDT	Special Weather Statement	CYS	Converse	29 min
Jul 5, 3:02 PM MDT	Special Weather Statement	CYS	Converse	28 min
Jul 5, 3:11 PM MDT	Severe Thunderstorm Warning	CYS	Converse	39 min
Jul 5, 3:21 PM MDT	Special Weather Statement	CYS		24 min
Jul 5, 3:48 PM MDT	Special Weather Statement	CYS	Platte	42 min
Jul 5, 3:55 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Converse	50 min
Jul 5, 4:01 PM MDT	Special Weather Statement	CYS	Converse	44 min
Jul 5, 4:39 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Platte	51 min
Jul 5, 4:47 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Converse, Platte	43 min
Jul 5, 5:02 PM MDT	Flash Flood Warning	CYS	Albany	5 hr
Jul 5, 5:26 PM MDT	Special Weather Statement	CYS	Platte	49 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2012 Every severe thunderstorm warning in 2012

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.