Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 143, NWS Cheyenne, WY

September 13, 2021Albany County, Carbon County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Sep 13, 2021, 3:59 AM MDT for Albany County, Carbon County, Wyoming. It was in force for 46 min. 1 report 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: Sep 13, 2021, 3:59 AM MDT (09:59 UTC)
Expired: Sep 13, 2021, 4:45 AM MDT
In force: 46 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Albany County, WY, Carbon County, WY

The radar

The Cheyenne radar (KCYS), 154 km from the middle of the area, began a volume at 10:00 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
Sep 13, 4:02 AM MDT	TSTM WND GST 62	15 E Sinclair, WY	MESONET STATION WY15 14.5 E SINCLAIR (WYDOT).

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 10.0 hours before the alert went out and 215 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: 55 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 3003 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 127 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

730 
WUUS55 KCYS 130959
SVRCYS
WYC001-007-131045-
/O.NEW.KCYS.SV.W.0143.210913T0959Z-210913T1045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Cheyenne WY
359 AM MDT Mon Sep 13 2021

The National Weather Service in Cheyenne has issued a

* Severe Thunderstorm Warning for...
  East central Carbon County in south central Wyoming...
  Northwestern Albany County in southeastern Wyoming...

* Until 445 AM MDT.

* At 359 AM MDT, severe thunderstorms were located along a line
  extending from 9 miles east of Seminoe Campground to 7 miles
  southeast of Teton Reservoir, moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Hanna, Medicine Bow, Elk Mountain and Arlington. 

This includes Interstate 80 in Wyoming between mile markers 225 and
276.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4194 10599 4154 10614 4159 10717 4193 10692
TIME...MOT...LOC 0959Z 274DEG 38KT 4217 10671 4156 10713 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Mokry

2 follow-up statements

600 
WWUS55 KCYS 131007
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
407 AM MDT Mon Sep 13 2021

WYC001-007-131045-
/O.CON.KCYS.SV.W.0143.000000T0000Z-210913T1045Z/
Carbon WY-Albany WY-
407 AM MDT Mon Sep 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 AM MDT
FOR EAST CENTRAL CARBON AND NORTHWESTERN ALBANY COUNTIES...

At 406 AM MDT, severe thunderstorms were located along a line
extending from 13 miles east of Seminoe Campground to 11 miles east 
of Teton Reservoir, moving east at 45 mph. Walcott Junction WYDOT 
sensor along Interstate 80 measuring wind gusts of 62 mph. 

HAZARD...60 mph wind gusts.

SOURCE...WYDOT sensor along Interstate 80.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Hanna, Medicine Bow, Elk Mountain and Arlington. 

This includes Interstate 80 in Wyoming between mile markers 225 and
276.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4194 10599 4154 10614 4159 10717 4193 10692
TIME...MOT...LOC 1006Z 274DEG 38KT 4217 10663 4156 10705 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Mokry

387 
WWUS55 KCYS 131039
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
439 AM MDT Mon Sep 13 2021

WYC001-007-131048-
/O.EXP.KCYS.SV.W.0143.000000T0000Z-210913T1045Z/
Carbon WY-Albany WY-
439 AM MDT Mon Sep 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL CARBON AND
NORTHWESTERN ALBANY COUNTIES WILL EXPIRE AT 445 AM MDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

LAT...LON 4194 10599 4154 10614 4159 10717 4193 10692
TIME...MOT...LOC 1038Z 274DEG 38KT 4215 10622 4154 10664 

$$

Mokry

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 13, 3:45 AM MDT	Special Weather Statement	CYS	Carbon	45 min
Sep 13, 4:40 AM MDT	Special Weather Statement	CYS	Albany	50 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.