Alert archive / Utah / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 51, NWS Salt Lake City, UT

July 31, 2021Morgan County, Rich County, Summit County, Utah; Uinta County, Wyoming

NWS Salt Lake City, UT issued this severe thunderstorm warning at Jul 31, 2021, 2:47 PM MDT for Morgan County, Rich County, Summit County, Utah; Uinta County, Wyoming. It was in force for 28 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 31, 2021, 2:47 PM MDT (20:47 UTC)
Expired
Jul 31, 2021, 3:15 PM MDT
In force
28 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Morgan County, UT, Rich County, UT, Summit County, UT, Uinta County, WY

The radar

The Salt Lake City radar (KMTX), 97 km from the middle of the area, began a volume at 20:49 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 nearest sounding before it

Salt Lake City I, UT (KSLC), launched 12:00Z, 8.8 hours before the alert went out and 57 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, Salt Lake City I, UT at 12:00Z on 2021-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 149 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, Salt Lake City I, UT at 12:00Z on 2021-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.1939Sfc1 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
149 J/kg
Mixed-layer CIN
-128 J/kg
Mixed-layer LCL
1716 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

022 
WUUS55 KSLC 312047
SVRSLC
UTC029-033-043-WYC041-312115-
/O.NEW.KSLC.SV.W.0051.210731T2047Z-210731T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
247 PM MDT Sat Jul 31 2021

The National Weather Service in Salt Lake City has issued a

* Severe Thunderstorm Warning for...
  Southern Rich County in northern Utah...
  East central Morgan County in northern Utah...
  Northwestern Summit County in northern Utah...
  Southwestern Uinta County in southwestern Wyoming...

* Until 315 PM MDT

* At 246 PM MDT, a severe thunderstorm was located near Coalville,
  moving northeast 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...
  Coalville, Henefer, Emory, Croydon, Castle Rock, Echo and Echo
  Reservoir.

This includes the following highways...
 Interstate 84 between mile markers 110 and 119.
 Interstate 80 in Utah between mile markers 163 and 190.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near Lost Creek Reservoir, get away from the water and move 
indoors or inside a vehicle. Remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

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

&&

LAT...LON 4090 11139 4106 11157 4129 11126 4110 11101
TIME...MOT...LOC 2046Z 225DEG 20KT 4101 11139 

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

ND
2 follow-up statements
596 
WWUS55 KSLC 312056
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
256 PM MDT Sat Jul 31 2021

UTC029-033-043-WYC041-312115-
/O.CON.KSLC.SV.W.0051.000000T0000Z-210731T2115Z/
Rich UT-Morgan UT-Summit UT-Uinta WY-
256 PM MDT Sat Jul 31 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 315 PM MDT
FOR SOUTHERN RICH...EAST CENTRAL MORGAN...NORTHWESTERN SUMMIT AND
SOUTHWESTERN UINTA COUNTIES...

At 256 PM MDT, a severe thunderstorm was located 9 miles north of
Coalville, moving northeast 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...
Coalville, Henefer, Emory, Croydon, Castle Rock, Echo and Echo
Reservoir.

This includes the following highways...
 Interstate 84 between mile markers 110 and 119.
 Interstate 80 in Utah between mile markers 163 and 190.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near Lost Creek Reservoir, get away from the water and move 
indoors or inside a vehicle. remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

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

&&

LAT...LON 4090 11139 4106 11157 4129 11126 4110 11101
TIME...MOT...LOC 2056Z 225DEG 20KT 4105 11134 

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

ND
956 
WWUS55 KSLC 312108
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
308 PM MDT Sat Jul 31 2021

UTC029-033-043-WYC041-312118-
/O.EXP.KSLC.SV.W.0051.000000T0000Z-210731T2115Z/
Rich UT-Morgan UT-Summit UT-Uinta WY-
308 PM MDT Sat Jul 31 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN RICH...EAST CENTRAL
MORGAN...NORTHWESTERN SUMMIT AND SOUTHWESTERN UINTA COUNTIES WILL
EXPIRE AT 315 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 small hail
and gusty winds are still possible with this thunderstorm.

LAT...LON 4090 11139 4106 11157 4129 11126 4110 11101
TIME...MOT...LOC 2108Z 225DEG 20KT 4108 11129 

$$

ND

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 7:17 PM MDTSpecial Weather StatementSLCBeaver43 min
Jul 30, 7:31 PM MDTSpecial Weather StatementSLC44 min
Jul 31, 12:31 PM MDTSpecial Weather StatementSLCSummit44 min
Jul 31, 1:12 PM MDTSpecial Weather StatementSLCIron33 min
Jul 31, 1:23 PM MDTFlash Flood Warning Considerable damage threatSLCDuchesne, Wasatch3 hr
Jul 31, 1:30 PM MDTSevere Thunderstorm WarningSLCIron, Washington30 min
Jul 31, 1:39 PM MDTSpecial Weather StatementSLCMorgan36 min
Jul 31, 2:10 PM MDTSpecial Weather StatementSLCMorgan50 min
Jul 31, 2:38 PM MDTSpecial Weather StatementSLCMorgan37 min
Jul 31, 2:52 PM MDTSpecial Weather StatementSLCRich23 min
Jul 31, 3:00 PM MDTAreal Flood AdvisorySLCIron107 min
Jul 31, 3:10 PM MDTSpecial Weather StatementSLCMorgan20 min
Jul 31, 3:16 PM MDTSevere Thunderstorm WarningSLCBox Elder, Cache, Weber29 min
Jul 31, 3:35 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Jul 31, 3:41 PM MDTSpecial Weather StatementSLCCache19 min
Jul 31, 4:00 PM MDTSevere Thunderstorm WarningSLCIron30 min
Jul 31, 4:06 PM MDTSpecial Weather StatementSLCBeaver24 min
Jul 31, 4:10 PM MDTFlash Flood Warning Considerable damage threatSLCUtah3 hr
Jul 31, 4:19 PM MDTFlash Flood Warning Considerable damage threatSLCDuchesne3 hr
Jul 31, 4:39 PM MDTSpecial Weather StatementSLCRich66 min
Jul 31, 5:01 PM MDTSpecial Weather StatementSLC29 min
Jul 31, 5:11 PM MDTFlash Flood Warning Considerable damage threatSLCWashington3 hr
Jul 31, 5:25 PM MDTSpecial Weather StatementSLCJuab35 min
Jul 31, 5:37 PM MDTSpecial Weather StatementSLCWashington38 min
Jul 31, 5:39 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington5 hr

Nearby

Severe Thunderstorm Warnings in Utah, 2021Severe 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.