Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 97, NWS Cheyenne, WY

July 9, 2021Goshen County, Platte County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Jul 9, 2021, 10:19 PM MDT for Goshen County, Platte County, Wyoming. It was in force for 41 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 9, 2021, 10:19 PM MDT (04:19 UTC)
Expired
Jul 9, 2021, 11:00 PM MDT
In force
41 min
Issued by
NWS Cheyenne, WY
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Goshen County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 83 km from the middle of the area, began a volume at 04:19 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 9, 2:16 PM MDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 4.3 hours before the alert went out and 266 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-pSkew-T log-p diagram, Denver, CO at 00:00Z on 2021-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 807 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2021-07-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
807 J/kg
Mixed-layer CIN
-117 J/kg
Mixed-layer LCL
3619 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
173 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

547 
WUUS55 KCYS 100419
SVRCYS
WYC015-031-100500-
/O.NEW.KCYS.SV.W.0097.210710T0419Z-210710T0500Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
1019 PM MDT Fri Jul 9 2021

The National Weather Service in Cheyenne has issued a

* Severe Thunderstorm Warning for...
  Southwestern Goshen County in southeastern Wyoming...
  Southern Platte County in southeastern Wyoming...

* Until 1100 PM MDT.

* At 1018 PM MDT, severe thunderstorms were located along a line
  extending from near Lakeview North to 6 miles west of Westview
  Circle, moving southeast at 35 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...
  Wheatland, Chugwater, Chugcreek, Lakeview North, Bordeaux, Westview
  Circle, Y-O Ranch, Grayrocks Reservoir and Slater.

This includes Interstate 25 in Wyoming between mile markers 53 and
88.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4167 10508 4211 10524 4223 10479 4181 10440
TIME...MOT...LOC 0418Z 332DEG 31KT 4213 10487 4206 10519 

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

Brothers
2 follow-up statements
523 
WWUS55 KCYS 100430
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
1030 PM MDT Fri Jul 9 2021

WYC015-031-100500-
/O.CON.KCYS.SV.W.0097.000000T0000Z-210710T0500Z/
Goshen WY-Platte WY-
1030 PM MDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1100 PM MDT
FOR SOUTHWESTERN GOSHEN AND SOUTHERN PLATTE COUNTIES...

At 1029 PM MDT, severe thunderstorms were located along a line
extending from 7 miles east of Chugcreek to 7 miles west of Bordeaux,
moving southeast at 40 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...
Wheatland, Chugwater, Chugcreek, Lakeview North, Bordeaux, Westview
Circle, Y-O Ranch, Grayrocks Reservoir and Slater.

This includes Interstate 25 in Wyoming between mile markers 53 and
84.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4167 10508 4208 10520 4218 10474 4181 10440
TIME...MOT...LOC 0429Z 329DEG 37KT 4202 10478 4195 10510 

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

Brothers
549 
WWUS55 KCYS 100459
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
1059 PM MDT Fri Jul 9 2021

WYC015-031-100508-
/O.EXP.KCYS.SV.W.0097.000000T0000Z-210710T0500Z/
Goshen WY-Platte WY-
1059 PM MDT Fri Jul 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN GOSHEN AND
SOUTHERN PLATTE COUNTIES WILL EXPIRE AT 1100 PM MDT...
    
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore, the warning will
be allowed to expire.  However small hail and gusty winds are still
possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
southeastern Wyoming.

LAT...LON 4167 10508 4208 10520 4218 10474 4181 10440
TIME...MOT...LOC 0458Z 332DEG 31KT 4181 10463 4174 10495 

$$

Brothers

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 7:25 PM MDTSevere Thunderstorm WarningCYSNiobrara50 min
Jul 9, 8:04 PM MDTSevere Thunderstorm WarningCYSNiobrara41 min
Jul 9, 8:31 PM MDTTornado WarningCYSNiobrara44 min
Jul 9, 9:47 PM MDTSpecial Weather StatementCYSPlatte28 min
Jul 9, 10:58 PM MDTSpecial Weather StatementCYSGoshen32 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2021Every 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.