Alert archive / Wyoming / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 93, NWS Salt Lake City, UT

August 21, 2021Uinta County, Wyoming

NWS Salt Lake City, UT issued this severe thunderstorm warning at Aug 21, 2021, 7:45 PM MDT for Uinta County, Wyoming. It was in force for 30 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: Aug 21, 2021, 7:45 PM MDT (01:45 UTC)
Expired: Aug 21, 2021, 8:15 PM MDT
In force: 30 min
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Destructive
Hail: 0.75 in
Wind: 80.0 mph

County Uinta County, WY

The radar

The Salt Lake City radar (KMTX), 172 km from the middle of the area, began a volume at 01:47 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
Aug 21, 7:54 PM MDT	TSTM WND GST 58	4 Ese Leroy, WY	MEASURED AT THE WYDOT SITE ALONG INTERSTATE 80 AT FRENCH
Aug 21, 8:00 PM MDT	TSTM WND GST 58	10 Wnw Ft Bridger, WY	MUDDY CREEK RAWS REPORTED A PEAK WIND GUST OF 58 MPH. TIME ESTIMATED.

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

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 00:00Z, 1.8 hours before the alert went out and 143 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: 422 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 2862 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 171 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

079 
WUUS55 KSLC 220145
SVRSLC
WYC041-220215-
/O.NEW.KSLC.SV.W.0093.210822T0145Z-210822T0215Z/

BULLETIN - EAS ACTIVATION REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
745 PM MDT Sat Aug 21 2021

The National Weather Service in Salt Lake City has issued a

* Severe Thunderstorm Warning for...
  Northern Uinta County in southwestern Wyoming...

* Until 815 PM MDT

* At 745 PM MDT, a severe thunderstorm was located 13 miles northeast
  of Evanston, moving northeast at 55 mph.

  THIS IS A DESTRUCTIVE STORM FOR NORTHERN UINTA COUNTY FROM 
INTERSTATE 80 NORTH. 

  HAZARD...80 mph wind gusts. 

  SOURCE...Observed at First Divide. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be heavily damaged. Expect 
           considerable damage to roofs, windows, and vehicles. 
           Extensive tree damage and power outages are likely. 

* Locations impacted include...
  Lyman, Mountain View, Ragen, Millburne, Church Buttes, Fort
  Bridger, Altamont, Piedmont, Carter and Leroy.

This includes Interstate 80 in Wyoming between mile markers 8 and 56.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4130 11006 4114 11090 4158 11089 4158 11004
TIME...MOT...LOC 0145Z 244DEG 47KT 4137 11075 

THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

CRK

2 follow-up statements

600 
WWUS55 KSLC 220157
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
757 PM MDT Sat Aug 21 2021

WYC041-220215-
/O.CON.KSLC.SV.W.0093.000000T0000Z-210822T0215Z/
Uinta WY-
757 PM MDT Sat Aug 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM MDT
FOR NORTHEASTERN UINTA COUNTY...

At 756 PM MDT, a severe thunderstorm was located 16 miles northwest
of Lyman, or 23 miles northeast of Evanston, moving northeast at 55
mph.

HAZARD...70 mph wind gusts. 

SOURCE...Automated observations reported wind gusts in excess of 78 
         mph earlier.  Wind gusts in excess of 55 mph are still 
         being reported along I-80 in Uinta County, Wyoming. 

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings. 

Locations impacted include...
Lyman, Mountain View, Ragen, Church Buttes, Fort Bridger, Carter and
Leroy.

This includes Interstate 80 in Wyoming between mile markers 20 and
56.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4130 11006 4123 11070 4158 11075 4158 11004
TIME...MOT...LOC 0156Z 244DEG 47KT 4143 11058 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

CRK

946 
WWUS55 KSLC 220208
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
808 PM MDT Sat Aug 21 2021

WYC041-220218-
/O.EXP.KSLC.SV.W.0093.000000T0000Z-210822T0215Z/
Uinta WY-
808 PM MDT Sat Aug 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN UINTA COUNTY WILL
EXPIRE AT 815 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 gusty
winds are still possible with this thunderstorm.

LAT...LON 4130 11006 4123 11070 4158 11075 4158 11004
TIME...MOT...LOC 0208Z 244DEG 47KT 4149 11042 

$$

CRK

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 21, 7:08 PM MDT	Severe Thunderstorm Warning Considerable damage threat	SLC	Uinta	37 min
Aug 21, 7:41 PM MDT	Special Weather Statement	SLC	Uinta	49 min
Aug 21, 8:07 PM MDT	Special Weather Statement	SLC	Uinta	38 min
Aug 21, 9:16 PM MDT	Special Weather Statement	SLC	Uinta	44 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.