Alert archive / Utah / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 21, NWS Salt Lake City, UT

September 1, 2012Juab County, Sanpete County, Utah County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Sep 1, 2012, 1:47 PM MDT for Juab County, Sanpete County, Utah County, Utah. It was in force for 43 min. 1 report 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
Sep 1, 2012, 1:47 PM MDT (19:47 UTC)
Expired
Sep 1, 2012, 2:30 PM MDT
In force
43 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon

Counties Juab County, UT, Sanpete County, UT, Utah County, UT

The radar

The Salt Lake City radar (KMTX), 176 km from the middle of the area, began a volume at 19:48 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
Sep 1, 2:15 PM MDTHAIL 1Nephi, UTPENNY TO QUARTER SIZED HAIL BETWEEN MM230-235 ON INTERSTATE 15.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 1, 12:59 PM MDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 12:00Z, 7.8 hours before the alert went out and 114 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 2012-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 158 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 2012-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 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
158 J/kg
Mixed-layer CIN
-127 J/kg
Mixed-layer LCL
978 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

633 
WUUS55 KSLC 011947
SVRSLC
UTC023-039-049-012030-
/O.NEW.KSLC.SV.W.0021.120901T1947Z-120901T2030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
147 PM MDT SAT SEP 1 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN JUAB COUNTY IN UTAH
  NORTH CENTRAL SANPETE COUNTY IN UTAH
  SOUTH CENTRAL UTAH COUNTY IN UTAH

* UNTIL 230 PM MDT

* AT 143 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL...
  AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 6
  MILES NORTH OF MILLS...OR 16 MILES SOUTHWEST OF NEPHI...MOVING
  NORTHEAST AT 35 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  LEVAN... NEPHI... MONA AND FOUNTAIN GREEN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS IN EXCESS OF 60 MPH
AND/OR LARGE HAIL AT LEAST ONE INCH IN DIAMETER. FOR YOUR
PROTECTION...MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM MDT
SATURDAY EVENING FOR CENTRAL UTAH AND SOUTHWEST WYOMING.

&&

LAT...LON 4001 11184 3988 11143 3959 11148 3946 11206
      3961 11219
TIME...MOT...LOC 1948Z 234DEG 31KT 3959 11202

$$

MPS
3 follow-up statements
677 
WWUS55 KSLC 012003
SVSSLC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
203 PM MDT SAT SEP 1 2012

UTC023-039-049-012030-
/O.CON.KSLC.SV.W.0021.000000T0000Z-120901T2030Z/
JUAB UT-SANPETE UT-UTAH UT-
203 PM MDT SAT SEP 1 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 PM MDT
FOR SOUTH CENTRAL UTAH...NORTH CENTRAL SANPETE AND NORTHEASTERN JUAB
COUNTIES...

AT 201 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS
LOCATED NEAR NEPHI...MOVING NORTHEAST AT 35 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  NEPHI... MONA AND FOUNTAIN GREEN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM MDT
SATURDAY EVENING FOR CENTRAL UTAH AND SOUTHWEST WYOMING.

&&

LAT...LON 3952 11200 3968 11209 4001 11184 3988 11143
      3959 11148
TIME...MOT...LOC 2003Z 234DEG 31KT 3967 11188

$$

MPS
665 
WWUS55 KSLC 012016
SVSSLC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
216 PM MDT SAT SEP 1 2012

UTC023-039-049-012030-
/O.CON.KSLC.SV.W.0021.000000T0000Z-120901T2030Z/
JUAB UT-SANPETE UT-UTAH UT-
216 PM MDT SAT SEP 1 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 PM MDT
FOR SOUTH CENTRAL UTAH...NORTH CENTRAL SANPETE AND EAST CENTRAL JUAB
COUNTIES...

AT 213 PM MDT... CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
NEPHI...MOVING NORTHEAST AT 35 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  NEPHI
  FOUNTAIN GREEN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM IS CAPABLE OF PRODUCING A SIGNIFICANT AMOUNT OF HAIL. HAIL
MAY ACCUMULATE ON AREA ROADS INCLUDING I-15 NEAR NEPHI RESULTING IN 
DANGEROUS TRAVEL CONDITIONS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM MDT
SATURDAY EVENING FOR CENTRAL UTAH AND SOUTHWEST WYOMING.

&&

LAT...LON 3957 11191 3970 11196 3987 11177 3988 11143
      3959 11148
TIME...MOT...LOC 2016Z 234DEG 31KT 3971 11178

$$

MPS
447 
WWUS55 KSLC 012026
SVSSLC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
226 PM MDT SAT SEP 1 2012

UTC023-039-049-012036-
/O.EXP.KSLC.SV.W.0021.000000T0000Z-120901T2030Z/
JUAB UT-SANPETE UT-UTAH UT-
226 PM MDT SAT SEP 1 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL UTAH...NORTH
CENTRAL SANPETE AND EAST CENTRAL JUAB COUNTIES WILL EXPIRE AT 230 PM
MDT...

THE STORM HAS WEAKENED AND IS NO LONGER SEVERE. THEREFORE THE WARNING
HAS BEEN ALLOWED TO EXPIRE.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM MDT FOR 
THE AREA. CONDITIONS REMAIN FAVORABLE FOR THE DEVELOPMENT OF SEVERE 
THUNDERSTORMS. PLEASE STAY TUNED TO NOAA WEATHER RADIO OR LOCAL MEDIA
OUTLETS FOR ADDITIONAL SEVERE WEATHER INFORMATION.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM MDT
SATURDAY EVENING FOR CENTRAL UTAH AND SOUTHWEST WYOMING.

LAT...LON 3957 11191 3970 11196 3987 11177 3988 11143
      3959 11148
TIME...MOT...LOC 2026Z 234DEG 31KT 3976 11169

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 7:47 PM MDTSevere Thunderstorm WarningSLCBox Elder, Tooele58 min
Aug 31, 8:42 PM MDTSevere Thunderstorm WarningSLCBox Elder, Tooele78 min
Aug 31, 9:40 PM MDTSevere Thunderstorm WarningSLCBox Elder, Davis, Tooele, Weber35 min
Aug 31, 10:20 PM MDTSpecial Weather StatementSLCCache, Davis, Morgan, Rich, Weber70 min
Sep 1, 11:04 AM MDTSpecial Weather StatementSLCMillard56 min
Sep 1, 12:01 PM MDTSpecial Weather StatementSLCMillard59 min
Sep 1, 12:40 PM MDTSevere Thunderstorm WarningSLCJuab, Millard50 min
Sep 1, 1:19 PM MDTSpecial Weather StatementSLC41 min
Sep 1, 1:32 PM MDTSpecial Weather StatementSLCJuab43 min
Sep 1, 1:34 PM MDTFlash Flood WarningSLCJuab, Millard4 hr
Sep 1, 1:46 PM MDTSevere Thunderstorm WarningSLCMillard32 min
Sep 1, 2:05 PM MDTSpecial Weather StatementSLCEmery40 min
Sep 1, 2:34 PM MDTSpecial Weather StatementSLCUtah56 min
Sep 1, 2:38 PM MDTSevere Thunderstorm WarningSLCTooele37 min
Sep 1, 3:01 PM MDTFlash Flood WarningSLCCarbon, Emery3 hr
Sep 1, 3:17 PM MDTSevere Thunderstorm WarningSLCTooele58 min
Sep 1, 4:16 PM MDTSevere Thunderstorm WarningSLCBox Elder, Tooele59 min
Sep 1, 4:42 PM MDTSpecial Weather StatementSLCWeber48 min
Sep 1, 5:10 PM MDTSpecial Weather StatementSLCWeber20 min
Sep 1, 5:26 PM MDTSpecial Weather StatementSLCDavis49 min
Sep 1, 5:33 PM MDTSevere Thunderstorm WarningSLCTooele57 min
Sep 1, 5:40 PM MDTSevere Thunderstorm WarningSLCDavis30 min
Sep 1, 5:52 PM MDTSevere Thunderstorm WarningSLCDavis, Morgan, Summit, Weber38 min

Nearby

Severe Thunderstorm Warnings in Utah, 2012Every severe thunderstorm warning in 2012

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.