Alert archive / Utah / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 8, NWS Salt Lake City, UT

April 21, 20115 counties in Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Apr 21, 2011, 12:55 PM MDT for 5 counties in Utah. It was in force for 35 min. 10 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
Apr 21, 2011, 12:55 PM MDT (18:55 UTC)
Expired
Apr 21, 2011, 1:30 PM MDT
In force
35 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon

Counties Juab County, UT, Morgan County, UT, Salt Lake County, UT, Tooele County, UT, Utah County, UT

The radar

The Salt Lake City radar (KMTX), 82 km from the middle of the area, began a volume at 18:54 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

TimeReportWhereRemark
Apr 21, 1:00 PM MDTNON-TSTM WND GST 653 W Faust, UTFAUST SENSOR
Apr 21, 1:05 PM MDTTSTM WND GST 584 Nne Stansbury Park, UTLAKE POINT SENSOR
Apr 21, 1:14 PM MDTTSTM WND GST 672 W Salt Lake City, UTSALT LAKE CITY AIRPORT SENSOR
Apr 21, 1:15 PM MDTTSTM WND DMGSlc Intl Arpt, UTLIGHT POLE FELL ON 2 CARS AT SALT LAKE INTERNATIONAL AIRPORT
Apr 21, 1:15 PM MDTTSTM WND GST 834 Ne Vernon, UTVERNON HILL SENSOR
Apr 21, 1:20 PM MDTTSTM WND GST 625 Sw West Valley City, UTBACCUS SENSOR
Apr 21, 1:24 PM MDTTSTM WND GST 619 Sw Lehi, UT
Apr 21, 1:25 PM MDTTSTM WND DMG2 Wnw Salt Lake City, UTLARGE TREES DOWN IN ROSE PARK
Apr 21, 1:30 PM MDTTSTM WND DMG1 N Salt Lake City, UT18-24 INCH DIAMETER TREE SNAPPED AND LANDED ON HOUSE CAUSING MINOR ROOF DAMAGE IN THE AVENUES
Apr 21, 1:30 PM MDTTSTM WND GST 625 Ne Holladay, UTPARLEYS CANYON AT QUARRY, UT - UTQRY

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 12:00Z, 6.9 hours before the alert went out and 27 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 2011-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 411 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°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 2011-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 square meters per square second.1939587897Sfc1 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
411 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
1122 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

130 
WUUS55 KSLC 211855
SVRSLC
UTC023-029-035-045-049-211930-
/O.NEW.KSLC.SV.W.0008.110421T1855Z-110421T1930Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1255 PM MDT THU APR 21 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL JUAB COUNTY IN UTAH
  SOUTHWESTERN MORGAN COUNTY IN UTAH
  SALT LAKE COUNTY IN UTAH
  SOUTHEASTERN TOOELE COUNTY IN UTAH
  WESTERN UTAH COUNTY IN UTAH

* UNTIL 130 PM MDT

* AT 1250 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM 7 MILES NORTH OF GRANTSVILLE TO 26 MILES WEST OF LITTLE SAHARA
  STATE PARK...MOVING EAST AT 50 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  ERDA... STOCKTON... STANSBURY PARK... VERNON... LAKE POINT...
  TOOELE... FAUST... LOFGREEN... MAGNA... COPPERTON... WEST VALLEY
  CITY... KEARNS... LITTLE SAHARA STATE PARK... HERRIMAN AND WEST
  JORDAN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3968 11210 3960 11280 4076 11247 4083 11230
      4077 11226 4093 11200 4092 11195 4086 11197
      4083 11192 4085 11175 4091 11176 4092 11170
TIME...MOT...LOC 1855Z 254DEG 43KT 4070 11235 3971 11265

$$

CRK
2 follow-up statements
399 
WUUS55 KSLC 211856 CCA
SVRSLC
UTC023-029-035-045-049-211930-
/O.COR.KSLC.SV.W.0008.110421T1855Z-110421T1930Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1255 PM MDT THU APR 21 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL JUAB COUNTY IN UTAH
  SOUTHWESTERN MORGAN COUNTY IN UTAH
  SALT LAKE COUNTY IN UTAH
  SOUTHEASTERN TOOELE COUNTY IN UTAH
  WESTERN UTAH COUNTY IN UTAH

* UNTIL 130 PM MDT

* AT 1250 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM 7 MILES NORTH OF GRANTSVILLE TO 26 MILES WEST OF LITTLE SAHARA
  STATE PARK...MOVING EAST AT 50 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  ERDA... STOCKTON... STANSBURY PARK... VERNON... LAKE POINT...
  TOOELE... FAUST... LOFGREEN... MAGNA... COPPERTON... WEST VALLEY
  CITY... KEARNS... LITTLE SAHARA STATE PARK... HERRIMAN AND WEST
  JORDAN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3968 11210 3960 11280 4076 11247 4083 11230
      4077 11226 4093 11200 4092 11195 4086 11197
      4083 11192 4085 11175 4091 11176 4092 11170
TIME...MOT...LOC 1855Z 254DEG 43KT 4070 11235 3971 11265

$$

CRK
909 
WWUS55 KSLC 211916
SVSSLC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
116 PM MDT THU APR 21 2011

UTC023-029-035-045-049-211930-
/O.CON.KSLC.SV.W.0008.000000T0000Z-110421T1930Z/
JUAB UT-TOOELE UT-UTAH UT-SALT LAKE UT-MORGAN UT-
116 PM MDT THU APR 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 PM MDT
FOR SOUTHWESTERN MORGAN...SALT LAKE...WESTERN UTAH...SOUTHEASTERN
TOOELE AND CENTRAL JUAB COUNTIES...

AT 113 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM MAGNA TO 9 MILES WEST OF LITTLE SAHARA STATE PARK...
MOVING EAST AT 50 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  WEST VALLEY CITY... KEARNS... HERRIMAN... LITTLE SAHARA STATE
  PARK... WEST JORDAN... SOUTH JORDAN... TINTIC JUNCTION...
  TAYLORSVILLE... JERICHO... SALT LAKE CITY... SOUTH SALT LAKE...
  RIVERTON... BLUFFDALE... FAIRFIELD AND EUREKA

LAT...LON 3968 11210 3962 11263 4077 11226 4093 11200
      4092 11195 4086 11197 4083 11187 4085 11175
      4091 11176 4092 11170
TIME...MOT...LOC 1916Z 254DEG 43KT 4077 11203 3978 11234

$$

CRK

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 10:41 AM MDTWind AdvisorySLC10 hr
Apr 21, 11:03 AM MDTSpecial Weather StatementSLCTooele57 min
Apr 21, 11:12 AM MDTSevere Thunderstorm WarningSLCBox Elder, Tooele48 min
Apr 21, 11:39 AM MDTSpecial Weather StatementSLCRich51 min
Apr 21, 11:55 AM MDTSpecial Weather StatementSLCTooele50 min
Apr 21, 12:12 PM MDTSevere Thunderstorm WarningSLCBox Elder, Tooele48 min
Apr 21, 12:25 PM MDTHigh Wind WarningSLC6 hr
Apr 21, 12:29 PM MDTSevere Thunderstorm WarningSLCBox Elder46 min
Apr 21, 12:33 PM MDTSpecial Weather StatementSLCRich27 min
Apr 21, 12:37 PM MDTSevere Thunderstorm WarningSLCJuab, Tooele23 min
Apr 21, 12:43 PM MDTSevere Thunderstorm WarningSLCDavis, Weber17 min
Apr 21, 12:52 PM MDTSevere Thunderstorm WarningSLCBox Elder, Cache, Davis, Morgan, Tooele, Weber23 min
Apr 21, 1:12 PM MDTSevere Thunderstorm WarningSLCBox Elder, Cache, Davis, Morgan, Salt Lake, Tooele and 1 more48 min
Apr 21, 1:24 PM MDTSevere Thunderstorm WarningSLCJuab, Salt Lake, Tooele, Utah36 min
Apr 21, 1:45 PM MDTSevere Thunderstorm WarningSLCBox Elder, Cache, Davis, Morgan, Rich, Salt Lake and 3 more30 min
Apr 21, 1:55 PM MDTSpecial Weather StatementSLCUtah, Wasatch50 min
Apr 21, 2:10 PM MDTSpecial Weather StatementSLCCarbon50 min
Apr 21, 2:14 PM MDTSevere Thunderstorm WarningSLCCache, Morgan, Rich, Summit46 min
Apr 21, 2:16 PM MDTSevere Thunderstorm WarningSLCCarbon29 min
Apr 21, 2:41 PM MDTSevere Thunderstorm WarningSLCRich35 min
Apr 21, 2:44 PM MDTSevere Thunderstorm WarningSLCCarbon16 min

Nearby

Severe Thunderstorm Warnings in Utah, 2011Every severe thunderstorm warning in 2011

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.