Alert archive / Utah / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 50, NWS Salt Lake City, UT

July 31, 2021Iron County, Washington County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Jul 31, 2021, 1:30 PM MDT for Iron County, Washington County, Utah. It was in force for 30 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 31, 2021, 1:30 PM MDT (19:30 UTC)
Expired
Jul 31, 2021, 2:00 PM MDT
In force
30 min
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

Counties Iron County, UT, Washington County, UT

The radar

The Cedar City radar (KICX), 90 km from the middle of the area, began a volume at 19:33 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

Las Vegas, NV (KVEF), launched 12:00Z, 7.5 hours before the alert went out and 213 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, Las Vegas, NV at 12:00Z on 2021-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 134 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, Las Vegas, NV at 12:00Z on 2021-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -17 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
134 J/kg
Mixed-layer CIN
-129 J/kg
Mixed-layer LCL
2161 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-17 m²/s²
0-3 km storm-relative helicity
49 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

365 
WUUS55 KSLC 311930
SVRSLC
UTC021-053-312000-
/O.NEW.KSLC.SV.W.0050.210731T1930Z-210731T2000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
130 PM MDT Sat Jul 31 2021

The National Weather Service in Salt Lake City has issued a

* Severe Thunderstorm Warning for...
  Northwestern Washington County in southwestern Utah...
  Southwestern Iron County in southern Utah...

* Until 200 PM MDT

* At 129 PM MDT, a severe thunderstorm was located 20 miles northeast
  of Beaver Dam, moving northwest at 15 mph.

  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...
  Modena.

This includes the following highways...
 Utah Route 18 between mile markers 50 and 51.
 Utah Route 56 between mile markers 2 and 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3792 11387 3772 11362 3758 11375 3769 11405
      3770 11405
TIME...MOT...LOC 1929Z 123DEG 12KT 3770 11377 

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

ND
2 follow-up statements
837 
WWUS55 KSLC 311945
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
145 PM MDT Sat Jul 31 2021

UTC053-311954-
/O.CAN.KSLC.SV.W.0050.000000T0000Z-210731T2000Z/
Washington UT-
145 PM MDT Sat Jul 31 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN WASHINGTON COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3792 11387 3775 11368 3763 11377 3769 11405
      3770 11405
TIME...MOT...LOC 1944Z 123DEG 12KT 3773 11383 

$$

UTC021-312000-
/O.CON.KSLC.SV.W.0050.000000T0000Z-210731T2000Z/
Iron UT-
145 PM MDT Sat Jul 31 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM MDT
FOR WEST CENTRAL IRON COUNTY...

At 144 PM MDT, a severe thunderstorm was located 19 miles northeast
of Beaver Dam, moving northwest at 15 mph.

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...
Modena.

This includes Utah Route 56 between mile markers 2 and 22.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3792 11387 3775 11368 3763 11377 3769 11405
      3770 11405
TIME...MOT...LOC 1944Z 123DEG 12KT 3773 11383 

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

ND
687 
WWUS55 KSLC 311954
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
154 PM MDT Sat Jul 31 2021

UTC021-312003-
/O.EXP.KSLC.SV.W.0050.000000T0000Z-210731T2000Z/
Iron UT-
154 PM MDT Sat Jul 31 2021

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL IRON COUNTY WILL
EXPIRE AT 200 PM MDT...
    
The severe thunderstorm which prompted the warning has weakened.
Therefore, the warning will be allowed to expire. However small hail 
and heavy rain are still possible with this thunderstorm.

LAT...LON 3792 11387 3775 11368 3763 11377 3769 11405
      3770 11405
TIME...MOT...LOC 1953Z 123DEG 12KT 3774 11385 

$$

ND

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 7:17 PM MDTSpecial Weather StatementSLCBeaver43 min
Jul 30, 7:31 PM MDTSpecial Weather StatementSLC44 min
Jul 31, 12:31 PM MDTSpecial Weather StatementSLCSummit44 min
Jul 31, 1:12 PM MDTSpecial Weather StatementSLCIron33 min
Jul 31, 1:23 PM MDTFlash Flood Warning Considerable damage threatSLCDuchesne, Wasatch3 hr
Jul 31, 1:39 PM MDTSpecial Weather StatementSLCMorgan36 min
Jul 31, 2:10 PM MDTSpecial Weather StatementSLCMorgan50 min
Jul 31, 2:38 PM MDTSpecial Weather StatementSLCMorgan37 min
Jul 31, 2:47 PM MDTSevere Thunderstorm WarningSLCMorgan, Rich, Summit28 min
Jul 31, 2:52 PM MDTSpecial Weather StatementSLCRich23 min
Jul 31, 3:00 PM MDTAreal Flood AdvisorySLCIron107 min
Jul 31, 3:10 PM MDTSpecial Weather StatementSLCMorgan20 min
Jul 31, 3:16 PM MDTSevere Thunderstorm WarningSLCBox Elder, Cache, Weber29 min
Jul 31, 3:35 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Jul 31, 3:41 PM MDTSpecial Weather StatementSLCCache19 min
Jul 31, 4:00 PM MDTSevere Thunderstorm WarningSLCIron30 min
Jul 31, 4:06 PM MDTSpecial Weather StatementSLCBeaver24 min
Jul 31, 4:10 PM MDTFlash Flood Warning Considerable damage threatSLCUtah3 hr
Jul 31, 4:19 PM MDTFlash Flood Warning Considerable damage threatSLCDuchesne3 hr
Jul 31, 4:39 PM MDTSpecial Weather StatementSLCRich66 min
Jul 31, 5:01 PM MDTSpecial Weather StatementSLC29 min
Jul 31, 5:11 PM MDTFlash Flood Warning Considerable damage threatSLCWashington3 hr
Jul 31, 5:25 PM MDTSpecial Weather StatementSLCJuab35 min
Jul 31, 5:37 PM MDTSpecial Weather StatementSLCWashington38 min
Jul 31, 5:39 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington5 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.