Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 69, NWS Cheyenne, WY

July 2, 2021Niobrara County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jul 2, 2021, 6:30 PM MDT for Niobrara County, Wyoming. It was in force for 30 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, 6:30 PM MDT (00:30 UTC)
Expired: Jul 2, 2021, 7:00 PM MDT
In force: 30 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Niobrara County, WY

The radar

The Rapid City radar (KUDX), 139 km from the middle of the area, began a volume at 00:33 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 00:00Z, 0.5 hours before the alert went out and 132 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: 1233 J/kg
Mixed-layer CIN: -11 J/kg
Mixed-layer LCL: 2200 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 151 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.5

Open this sounding in Storm Lab

The text

As transmitted.

911 
WUUS55 KCYS 030030
SVRCYS
WYC027-030100-
/O.NEW.KCYS.SV.W.0069.210703T0030Z-210703T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
630 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 700 PM MDT.

* At 629 PM MDT, a severe thunderstorm was located over Mule Creek
  Junction, or 18 miles west of Edgemont, moving east at 10 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Mule Creek Junction.

This replaces the Severe Thunderstorm Warning which was previously 
in effect for the warned area. 

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 4321 10406 4328 10428 4342 10427 4344 10406
TIME...MOT...LOC 0029Z 272DEG 9KT 4335 10419 

HAIL...1.00IN
WIND...60MPH
 
$$

Hammer

1 follow-up statement

324 
WWUS55 KCYS 030053
SVSCYS

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

WYC027-030103-
/O.EXP.KCYS.SV.W.0069.000000T0000Z-210703T0100Z/
Niobrara WY-
653 PM MDT Fri Jul 2 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN NIOBRARA COUNTY
WILL EXPIRE AT 700 PM MDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However small hail 
is still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Cheyenne.

LAT...LON 4321 10406 4328 10428 4342 10427 4344 10406
TIME...MOT...LOC 0053Z 272DEG 9KT 4335 10412 

$$

Hammer

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 2, 6:22 PM MDT	Special Weather Statement	CYS		38 min
Jul 2, 6:44 PM MDT	Special Weather Statement	CYS	Platte	46 min
Jul 2, 7:00 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Niobrara, Platte	60 min
Jul 2, 7:05 PM MDT	Special Weather Statement	CYS	Niobrara	40 min
Jul 2, 7:47 PM MDT	Severe Thunderstorm Warning	CYS	Goshen	36 min
Jul 3, 12:27 PM MDT	Special Weather Statement	CYS	Platte	48 min
Jul 3, 12:35 PM MDT	Special Weather Statement	CYS	Laramie	40 min
Jul 3, 1:47 PM MDT	Special Weather Statement	CYS	Laramie	43 min
Jul 3, 2:42 PM MDT	Special Weather Statement	CYS	Goshen	48 min
Jul 3, 3:01 PM MDT	Severe Thunderstorm Warning	CYS	Goshen	30 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.