Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 60, NWS Cheyenne, WY

June 18, 2021Laramie County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jun 18, 2021, 7:35 PM MDT for Laramie County, Wyoming. It was in force for 40 min. 5 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, 7:35 PM MDT (01:35 UTC)
Expired: Jun 18, 2021, 8:15 PM MDT
In force: 40 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Laramie County, WY

The radar

The Cheyenne radar (KCYS), 18 km from the middle of the area, began a volume at 01:36 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, 7:45 PM MDT	HAIL 1.5	4 Nw Cheyenne, WY	FACEBOOK POST. VANDEHEI AND I-25.
Jun 18, 7:55 PM MDT	HAIL 1.5	5 N Cheyenne, WY	QUARTER TO PING PONG BALL HAIL AT RANCHETTES.
Jun 18, 7:58 PM MDT	HAIL 1	3 Nnw Cheyenne, WY
Jun 18, 8:00 PM MDT	HAIL 1.25	6 Ne Cheyenne, WY
Jun 18, 8:05 PM MDT	HAIL 1.5	2 Nnw Cheyenne, WY

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, 1.6 hours before the alert went out and 197 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.

194 
WUUS55 KCYS 190135
SVRCYS
WYC021-190215-
/O.NEW.KCYS.SV.W.0060.210619T0135Z-210619T0215Z/

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

The National Weather Service in Cheyenne has issued a

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

* Until 815 PM MDT.

* At 734 PM MDT, a severe thunderstorm was located 9 miles north of
  Hillsdale, or 19 miles northeast of Cheyenne, moving east at 25 
  mph. Another possible severe thunderstorm was developing on the 
  north side of Cheyenne as well. 

  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...
  Cheyenne, Burns, Hillsdale, Ranchettes, North Cheyenne, Gun Barrel
  and Warren AFB.

This includes Interstate 25 in Wyoming between mile markers 13 and
23.
 
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 4116 10497 4130 10494 4150 10425 4121 10416
TIME...MOT...LOC 0134Z 258DEG 21KT 4134 10454 

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

Cox

2 follow-up statements

215 
WWUS55 KCYS 190148
SVSCYS

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

WYC021-190215-
/O.CON.KCYS.SV.W.0060.000000T0000Z-210619T0215Z/
Laramie WY-
748 PM MDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM MDT
FOR CENTRAL LARAMIE COUNTY...

At 747 PM MDT, a severe thunderstorm was located 8 miles north of 
Hillsdale, or 21 miles northeast of Cheyenne, moving east at 20 mph. 
Another severe thunderstorm was developing on the northern side of 
Cheyenne mainly along and north of Dell Range. 

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...
Cheyenne, Burns, Hillsdale, Ranchettes, North Cheyenne, Gun Barrel
and Warren AFB.

This includes Interstate 25 in Wyoming between mile markers 13 and
23.
 
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 4116 10497 4130 10494 4150 10425 4121 10416
TIME...MOT...LOC 0147Z 263DEG 18KT 4133 10447 

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

Cox

310 
WWUS55 KCYS 190201
SVSCYS

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

WYC021-190215-
/O.CON.KCYS.SV.W.0060.000000T0000Z-210619T0215Z/
Laramie WY-
801 PM MDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM MDT
FOR EAST CENTRAL LARAMIE COUNTY...

At 800 PM MDT, a severe thunderstorm was located near Gun Barrel, or
26 miles northeast of Cheyenne, moving east at 25 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...
Burns, Gun Barrel and Hillsdale. 

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 4119 10454 4137 10466 4150 10425 4121 10416
TIME...MOT...LOC 0200Z 258DEG 21KT 4135 10437 

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

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, 7:54 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	51 min
Jun 18, 8:13 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	47 min
Jun 18, 8:29 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	46 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.