Alert archive / Utah / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 43, NWS Salt Lake City, UT

July 28, 2021Box Elder County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Jul 28, 2021, 3:50 PM MDT for Box Elder County, Utah. It was in force for 25 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 28, 2021, 3:50 PM MDT (21:50 UTC)
Expired
Jul 28, 2021, 4:15 PM MDT
In force
25 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

County Box Elder County, UT

The radar

The Salt Lake City radar (KMTX), 54 km from the middle of the area, began a volume at 21:52 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, 9.8 hours before the alert went out and 110 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 2021-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 104 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 2021-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
104 J/kg
Mixed-layer CIN
-191 J/kg
Mixed-layer LCL
2082 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

995 
WUUS55 KSLC 282150
SVRSLC
UTC003-282215-
/O.NEW.KSLC.SV.W.0043.210728T2150Z-210728T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
350 PM MDT Wed Jul 28 2021

The National Weather Service in Salt Lake City has issued a

* Severe Thunderstorm Warning for...
  Northeastern Box Elder County in northern Utah...

* Until 415 PM MDT

* At 349 PM MDT, a severe thunderstorm was located 7 miles east of
  Howell, or 9 miles northwest of Tremonton, and is nearly
  stationary.

  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...
  Tremonton, Riverside, Garland, Bothwell and Thatcher. 

This includes the following highways...
 Interstate 15 between mile markers 381 and 386.
 Interstate 84 between mile markers 29 and 41.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4165 11226 4170 11240 4186 11237 4179 11211
TIME...MOT...LOC 2149Z 198DEG 2KT 4174 11231 

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

Webber
2 follow-up statements
007 
WWUS55 KSLC 282202
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
402 PM MDT Wed Jul 28 2021

UTC003-282215-
/O.CON.KSLC.SV.W.0043.000000T0000Z-210728T2215Z/
Box Elder UT-
402 PM MDT Wed Jul 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM MDT
FOR NORTHEASTERN BOX ELDER COUNTY...

At 401 PM MDT, a severe thunderstorm was located 7 miles east of
Howell, or 10 miles northwest of Tremonton, and is nearly stationary.

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...
Tremonton, Riverside, Garland, Bothwell and Thatcher. 

This includes the following highways...
 Interstate 15 between mile markers 381 and 386.
 Interstate 84 between mile markers 29 and 41.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4165 11226 4170 11240 4186 11237 4179 11211
TIME...MOT...LOC 2201Z 198DEG 2KT 4175 11231 

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

AD
664 
WWUS55 KSLC 282214
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
414 PM MDT Wed Jul 28 2021

UTC003-282223-
/O.EXP.KSLC.SV.W.0043.000000T0000Z-210728T2215Z/
Box Elder UT-
414 PM MDT Wed Jul 28 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN BOX ELDER COUNTY
WILL EXPIRE AT 415 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 and heavy rain are still possible with this thunderstorm.

LAT...LON 4165 11226 4170 11240 4186 11237 4179 11211
TIME...MOT...LOC 2213Z 198DEG 2KT 4175 11231 

$$

AD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 28, 11:57 AM MDTSpecial Weather StatementSLCCache48 min
Jul 28, 12:19 PM MDTFlash Flood WarningSLCCache3 hr
Jul 28, 1:55 PM MDTFlash Flood WarningSLCMorgan3 hr
Jul 28, 2:17 PM MDTFlash Flood Warning Considerable damage threatSLCEmery3 hr
Jul 28, 3:47 PM MDTFlash Flood WarningSLCDavis, Morgan3 hr

Nearby

Severe Thunderstorm Warnings in Utah, 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.