Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 63, NWS Cheyenne, WY

June 18, 2021Laramie County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jun 18, 2021, 8:29 PM MDT for Laramie 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: Jun 18, 2021, 8:29 PM MDT (02:29 UTC)
Expired: Jun 18, 2021, 9:15 PM MDT
In force: 46 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 29 km from the middle of the area, began a volume at 02:29 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
Jun 18, 8:33 PM MDT	HAIL 0.7	9 Ssw Hillsdale, WY
Jun 18, 8:50 PM MDT	HAIL 0.7	7 W Carpenter, WY	PEA TO DIME SIZED.

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, 2.5 hours before the alert went out and 171 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: 580 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 2917 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 78 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted.

855 
WUUS55 KCYS 190229
SVRCYS
WYC021-190315-
/O.NEW.KCYS.SV.W.0063.210619T0229Z-210619T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
829 PM MDT Fri Jun 18 2021

The National Weather Service in Cheyenne has issued a

* Severe Thunderstorm Warning for...
  Southeastern Laramie County in southeastern Wyoming...

* Until 915 PM MDT.

* At 829 PM MDT, a severe thunderstorm was located 8 miles southwest
  of Hillsdale, or 11 miles east of Cheyenne, moving east at 20 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...
  Carpenter.

This includes Interstate 80 in Wyoming between mile markers 375 and
391.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4103 10460 4118 10458 4118 10424 4100 10433
TIME...MOT...LOC 0229Z 280DEG 18KT 4111 10457 

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

Cox

3 follow-up statements

879 
WWUS55 KCYS 190248
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
848 PM MDT Fri Jun 18 2021

WYC021-190315-
/O.CON.KCYS.SV.W.0063.000000T0000Z-210619T0315Z/
Laramie WY-
848 PM MDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM MDT
FOR SOUTHEASTERN LARAMIE COUNTY...

At 847 PM MDT, a severe thunderstorm was located near Carpenter, or
19 miles east of Cheyenne, moving east at 25 mph.

HAZARD...Ping pong 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...
Carpenter.

This includes Interstate 80 in Wyoming between mile markers 379 and
391.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4102 10454 4118 10450 4118 10424 4100 10433
TIME...MOT...LOC 0247Z 284DEG 21KT 4108 10443 

HAIL...1.50IN
WIND...60MPH
 
$$

Cox

910 
WWUS55 KCYS 190301
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
901 PM MDT Fri Jun 18 2021

WYC021-190315-
/O.CON.KCYS.SV.W.0063.000000T0000Z-210619T0315Z/
Laramie WY-
901 PM MDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM MDT
FOR SOUTHEASTERN LARAMIE COUNTY...

At 901 PM MDT, a severe thunderstorm was located over Carpenter, or
24 miles east of Cheyenne, moving east at 20 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...
Carpenter.

This includes Interstate 80 in Wyoming between mile markers 383 and
391.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4102 10448 4118 10441 4118 10424 4100 10433
TIME...MOT...LOC 0301Z 280DEG 18KT 4107 10434 

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

Cox

145 
WWUS55 KCYS 190311
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
911 PM MDT Fri Jun 18 2021

WYC021-190321-
/O.EXP.KCYS.SV.W.0063.000000T0000Z-210619T0315Z/
Laramie WY-
911 PM MDT Fri Jun 18 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN LARAMIE COUNTY
WILL EXPIRE AT 915 PM MDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However small hail
and heavy rain are still possible with this thunderstorm.

LAT...LON 4102 10448 4118 10441 4118 10424 4100 10433
TIME...MOT...LOC 0311Z 280DEG 18KT 4106 10427 

$$

Cox

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 18, 7:18 PM MDT	Red Flag Warning	CYS		25 hr
Jun 18, 7:21 PM MDT	Special Weather Statement	CYS	Laramie	39 min
Jun 18, 7:35 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	40 min
Jun 18, 7:54 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	51 min
Jun 18, 8:13 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	47 min
Jun 18, 8:30 PM MDT	Special Weather Statement	CYS	Laramie	45 min
Jun 19, 12:54 PM MDT	Fire Weather Watch	CYS		7 hr
Jun 19, 1:18 PM MDT	Special Weather Statement	CYS	Laramie	42 min
Jun 19, 1:51 PM MDT	Special Weather Statement	CYS	Laramie	24 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.