Alert archive / Utah / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 108, NWS Salt Lake City, UT

September 12, 2021Box Elder County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Sep 12, 2021, 3:37 PM MDT for Box Elder County, Utah. It was in force for 23 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
Sep 12, 2021, 3:37 PM MDT (21:37 UTC)
Expired
Sep 12, 2021, 4:00 PM MDT
In force
23 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Box Elder County, UT

The radar

The Salt Lake City radar (KMTX), 108 km from the middle of the area, began a volume at 21:36 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

Elko, NV (KLKN), launched 12:00Z, 9.6 hours before the alert went out and 76 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, Elko, NV at 12:00Z on 2021-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Elko, NV at 12:00Z on 2021-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1594 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

407 
WUUS55 KSLC 122137
SVRSLC
UTC003-122200-
/O.NEW.KSLC.SV.W.0108.210912T2137Z-210912T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
337 PM MDT Sun Sep 12 2021

The National Weather Service in Salt Lake City has issued a

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

* Until 400 PM MDT

* At 336 PM MDT, a severe thunderstorm was located 16 miles northeast
  of Montello, moving east at 30 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...
  Lucin.

This includes Utah Route 30 between mile markers 0 and 31.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4164 11343 4135 11331 4124 11404 4137 11405
      4142 11404
TIME...MOT...LOC 2136Z 250DEG 27KT 4137 11391 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

CRK
1 follow-up statement
779 
WWUS55 KSLC 122147
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
347 PM MDT Sun Sep 12 2021

UTC003-122200-
/O.CON.KSLC.SV.W.0108.000000T0000Z-210912T2200Z/
Box Elder UT-
347 PM MDT Sun Sep 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM MDT
FOR WEST CENTRAL BOX ELDER COUNTY...

At 346 PM MDT, a severe thunderstorm was located 21 miles northeast 
of Montello, moving east at 30 mph. An additional strong 
thunderstorm is approaching the Utah/Nevada border southwest of 
Lucin.

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...
Lucin.

This includes Utah Route 30 between mile markers 0 and 31.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4164 11343 4135 11331 4124 11404 4137 11405
      4142 11404
TIME...MOT...LOC 2146Z 250DEG 27KT 4140 11381 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

CRK

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 11, 6:19 PM MDTFlash Flood Warning Considerable damage threatSLCEmery, Garfield, Wayne3 hr
Sep 11, 6:30 PM MDTSpecial Weather StatementSLCJuab45 min
Sep 11, 7:16 PM MDTSpecial Weather StatementSLCJuab44 min
Sep 11, 7:24 PM MDTSpecial Weather StatementSLC51 min
Sep 11, 8:15 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Sep 11, 8:22 PM MDTSpecial Weather StatementSLCSanpete38 min
Sep 11, 9:06 PM MDTSpecial Weather StatementSLCSanpete39 min
Sep 12, 3:29 PM MDTSpecial Weather StatementSLCBox Elder46 min
Sep 12, 3:54 PM MDTSevere Thunderstorm WarningSLCBox Elder51 min
Sep 12, 4:13 PM MDTSpecial Weather StatementSLCBox Elder47 min
Sep 12, 4:31 PM MDTSevere Thunderstorm WarningSLCBox Elder44 min
Sep 12, 4:42 PM MDTSevere Thunderstorm WarningSLCBox Elder24 min
Sep 12, 5:08 PM MDTSevere Thunderstorm WarningSLCBox Elder20 min
Sep 12, 5:14 PM MDTSpecial Weather StatementSLC46 min
Sep 12, 5:54 PM MDTSevere Thunderstorm WarningSLCBox Elder51 min

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.