Alert archive / Utah / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 79, NWS Salt Lake City, UT

August 17, 2021Juab County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Aug 17, 2021, 6:10 PM MDT for Juab County, Utah. It was in force for 35 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
Aug 17, 2021, 6:10 PM MDT (00:10 UTC)
Expired
Aug 17, 2021, 6:45 PM MDT
In force
35 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

County Juab County, UT

The radar

The Salt Lake City radar (KMTX), 182 km from the middle of the area, began a volume at 00:11 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 00:00Z, 0.2 hours before the alert went out and 122 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 00:00Z on 2021-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 920 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2021-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 square meters per square second.193958Sfc1 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
920 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
3268 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3

Open this sounding in Storm Lab

The text

As transmitted.

695 
WUUS55 KSLC 180010
SVRSLC
UTC023-180045-
/O.NEW.KSLC.SV.W.0079.210818T0010Z-210818T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
610 PM MDT Tue Aug 17 2021

The National Weather Service in Salt Lake City has issued a

* Severe Thunderstorm Warning for...
  East central Juab County in central Utah...

* Until 645 PM MDT

* At 610 PM MDT, a severe thunderstorm was located 12 miles west of
  Nephi, moving northeast at 45 mph.

  HAZARD...60 mph wind gusts and half dollar size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees. 

* Locations impacted include...
  Nephi and Mona. 

This includes Interstate 15 between mile markers 213 and 234.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3969 11171 3959 11172 3955 11210 3968 11219
      3986 11179 3975 11170
TIME...MOT...LOC 0010Z 240DEG 38KT 3965 11204 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

MPS
2 follow-up statements
154 
WWUS55 KSLC 180029
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
629 PM MDT Tue Aug 17 2021

UTC023-180045-
/O.CON.KSLC.SV.W.0079.000000T0000Z-210818T0045Z/
Juab UT-
629 PM MDT Tue Aug 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM MDT
FOR EAST CENTRAL JUAB COUNTY...

At 628 PM MDT, a severe thunderstorm was located over Nephi, moving
northeast at 45 mph.

HAZARD...60 mph wind gusts and penny size hail. 

SOURCE...Radar indicated. 

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

Locations impacted include...
Nephi and Mona. 

This includes Interstate 15 between mile markers 217 and 234.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3964 11172 3959 11202 3973 11207 3986 11179
      3975 11170 3969 11171
TIME...MOT...LOC 0028Z 240DEG 38KT 3975 11181 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

MPS
168 
WWUS55 KSLC 180044
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
644 PM MDT Tue Aug 17 2021

UTC023-180053-
/O.EXP.KSLC.SV.W.0079.000000T0000Z-210818T0045Z/
Juab UT-
644 PM MDT Tue Aug 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL JUAB COUNTY WILL
EXPIRE AT 645 PM MDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However small hail and gusty winds are still
possible with this thunderstorm.

LAT...LON 3964 11172 3959 11202 3973 11207 3986 11179
      3975 11170 3969 11171
TIME...MOT...LOC 0043Z 240DEG 38KT 3980 11170 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 6:05 PM MDTFlash Flood Warning Considerable damage threatSLCMillard3 hr
Aug 17, 6:31 PM MDTSevere Thunderstorm WarningSLCMillard59 min
Aug 17, 6:39 PM MDTSpecial Weather StatementSLCUtah36 min
Aug 17, 6:49 PM MDTSevere Thunderstorm WarningSLCUtah, Wasatch26 min
Aug 17, 6:57 PM MDTFlash Flood Warning Considerable damage threatSLCKane, San Juan5 hr
Aug 17, 7:14 PM MDTSevere Thunderstorm WarningSLCSummit, Wasatch31 min
Aug 17, 8:52 PM MDTSpecial Weather StatementSLCSalt Lake38 min
Aug 17, 9:30 PM MDTSpecial Weather StatementSLCTooele30 min
Aug 17, 9:55 PM MDTSpecial Weather StatementSLCKane35 min
Aug 17, 9:58 PM MDTSpecial Weather StatementSLCJuab32 min
Aug 17, 10:00 PM MDTSpecial Weather StatementSLCJuab30 min
Aug 17, 10:17 PM MDTSpecial Weather StatementSLCSalt Lake28 min
Aug 18, 12:23 AM MDTSpecial Weather StatementSLC52 min
Aug 18, 12:31 AM MDTSpecial Weather StatementSLCMillard44 min
Aug 18, 12:45 AM MDTSpecial Weather StatementSLCJuab45 min
Aug 18, 1:42 AM MDTSpecial Weather StatementSLCJuab48 min
Aug 18, 4:38 AM MDTFlash Flood Warning Considerable damage threatSLCIron5 hr
Aug 18, 4:41 AM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Aug 18, 6:02 AM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington4 hr
Aug 18, 7:30 AM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington90 min
Aug 18, 7:55 AM MDTAreal Flood WarningSLCGarfield, Iron, Kane, Washington6 hr
Aug 18, 8:58 AM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington92 min
Aug 18, 11:05 AM MDTSevere Thunderstorm WarningSLCTooele40 min
Aug 18, 11:45 AM MDTSpecial Weather StatementSLCSalt Lake45 min
Aug 18, 12:11 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne6 hr
Aug 18, 12:17 PM MDTAreal Flood AdvisorySLCDavis, Salt Lake, Tooele2 hr
Aug 18, 12:29 PM MDTSpecial Weather StatementSLC31 min
Aug 18, 12:34 PM MDTSevere Thunderstorm WarningSLCJuab, Tooele56 min
Aug 18, 12:47 PM MDTSpecial Weather StatementSLCPiute28 min
Aug 18, 1:05 PM MDTFlash Flood Warning Considerable damage threatSLCWayne3 hr
Aug 18, 1:12 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield2 hr
Aug 18, 1:14 PM MDTSpecial Weather StatementSLCBeaver31 min
Aug 18, 1:24 PM MDTAreal Flood WarningSLCJuab, Salt Lake, Tooele, Utah3 hr
Aug 18, 1:24 PM MDTSevere Thunderstorm WarningSLCJuab, Tooele, Utah81 min
Aug 18, 1:39 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington3 hr
Aug 18, 1:57 PM MDTAreal Flood AdvisorySLCSalt Lake, Utah2 hr
Aug 18, 2:27 PM MDTFlash Flood Warning Considerable damage threatSLCUtah3 hr
Aug 18, 2:37 PM MDTFlash Flood Warning Considerable damage threatSLCUtah113 min
Aug 18, 2:51 PM MDTSpecial Weather StatementSLCSummit24 min
Aug 18, 2:56 PM MDTSpecial Weather StatementSLCGarfield49 min
Aug 18, 3:14 PM MDTSpecial Weather StatementSLCKane46 min
Aug 18, 3:18 PM MDTSpecial Weather StatementSLCWasatch27 min
Aug 18, 3:25 PM MDTFlash Flood Warning Considerable damage threatSLCUtah3 hr
Aug 18, 3:41 PM MDTSpecial Weather StatementSLCSanpete49 min
Aug 18, 3:46 PM MDTFlash Flood Warning Considerable damage threatSLCEmery, Wayne3 hr
Aug 18, 4:16 PM MDTSpecial Weather StatementSLCKane44 min
Aug 18, 4:22 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield3 hr
Aug 18, 5:41 PM MDTSpecial Weather StatementSLC49 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.