Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 68, NWS Cheyenne, WY

July 2, 2021Niobrara County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jul 2, 2021, 5:42 PM MDT for Niobrara County, Wyoming. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 2, 2021, 5:42 PM MDT (23:42 UTC)
Expired: Jul 2, 2021, 6:30 PM MDT
In force: 48 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

County Niobrara County, WY

The radar

The Rapid City radar (KUDX), 141 km from the middle of the area, began a volume at 23:45 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.

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 11.7 hours before the alert went out and 134 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: 317 J/kg
Mixed-layer CIN: -153 J/kg
Mixed-layer LCL: 1062 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: 35 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

680 
WUUS55 KCYS 022342
SVRCYS
WYC027-030030-
/O.NEW.KCYS.SV.W.0068.210702T2342Z-210703T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
542 PM MDT Fri Jul 2 2021

The National Weather Service in Cheyenne has issued a

* Severe Thunderstorm Warning for...
  Northeastern Niobrara County in east central Wyoming...

* Until 630 PM MDT.

* At 541 PM MDT, a severe thunderstorm was located near Mule Creek
  Junction, or 26 miles west of Edgemont, moving east at 10 mph.

  HAZARD...Golf ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees.

* Locations impacted include...
  Mule Creek Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move immediately to shelter inside a strong building. Stay
away from windows.

&&

LAT...LON 4324 10405 4330 10446 4344 10445 4350 10406
TIME...MOT...LOC 2341Z 274DEG 9KT 4337 10433 

HAIL...1.75IN
WIND...60MPH
 
$$

Hammer

1 follow-up statement

662 
WWUS55 KCYS 030006
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
606 PM MDT Fri Jul 2 2021

WYC027-030030-
/O.CON.KCYS.SV.W.0068.000000T0000Z-210703T0030Z/
Niobrara WY-
606 PM MDT Fri Jul 2 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM MDT
FOR NORTHEASTERN NIOBRARA COUNTY...

At 605 PM MDT, a severe thunderstorm was located over Mule Creek
Junction, or 22 miles west of Edgemont, moving east at 10 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Mule Creek Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

LAT...LON 4324 10405 4332 10441 4345 10438 4350 10406
TIME...MOT...LOC 0005Z 273DEG 9KT 4337 10427 

HAIL...1.75IN
WIND...60MPH
 
$$

Hammer

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 1, 7:53 PM MDT	Areal Flood Advisory	CYS	Albany, Converse, Platte	116 min
Jul 2, 4:19 PM MDT	Special Weather Statement	CYS	Albany	26 min
Jul 2, 4:59 PM MDT	Special Weather Statement	CYS	Niobrara	31 min
Jul 2, 5:07 PM MDT	Special Weather Statement	CYS	Niobrara	38 min
Jul 2, 5:28 PM MDT	Special Weather Statement	CYS	Niobrara	47 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2021 Every severe thunderstorm warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.