Alert archive / Utah / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 63, NWS Salt Lake City, UT

August 13, 2021Washington County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Aug 13, 2021, 4:40 PM MDT for Washington 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 13, 2021, 4:40 PM MDT (22:40 UTC)
Expired: Aug 13, 2021, 5:15 PM MDT
In force: 35 min
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Washington County, UT

The radar

The Cedar City radar (KICX), 60 km from the middle of the area, began a volume at 22:44 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, 10.7 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 487 J/kg
Mixed-layer CIN: -323 J/kg
Mixed-layer LCL: 2453 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

422 
WUUS55 KSLC 132240
SVRSLC
UTC053-132315-
/O.NEW.KSLC.SV.W.0063.210813T2240Z-210813T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Salt Lake City UT
440 PM MDT Fri Aug 13 2021

The National Weather Service in Salt Lake City has issued a

* Severe Thunderstorm Warning for...
  Central Washington County in southwestern Utah...

* Until 515 PM MDT

* At 439 PM MDT, a severe thunderstorm was located 11 miles southwest
  of New Harmony, or 28 miles west of Zion National Park, moving
  south at 20 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...
  Pine Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3736 11362 3750 11343 3738 11335 3727 11343
TIME...MOT...LOC 2239Z 022DEG 17KT 3737 11345 

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

$$

AD

2 follow-up statements

419 
WWUS55 KSLC 132256
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
456 PM MDT Fri Aug 13 2021

UTC053-132315-
/O.CON.KSLC.SV.W.0063.000000T0000Z-210813T2315Z/
Washington UT-
456 PM MDT Fri Aug 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM MDT
FOR CENTRAL WASHINGTON COUNTY...

At 455 PM MDT, a severe thunderstorm was located 9 miles northwest of
Quail Creek State Park, or 29 miles west of Zion National Park,
moving south at 20 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...
Pine Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3736 11362 3750 11343 3738 11335 3727 11343
TIME...MOT...LOC 2255Z 022DEG 17KT 3730 11349 

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

$$

AD

489 
WWUS55 KSLC 132311
SVSSLC

Severe Weather Statement
National Weather Service Salt Lake City UT
511 PM MDT Fri Aug 13 2021

UTC053-132320-
/O.EXP.KSLC.SV.W.0063.000000T0000Z-210813T2315Z/
Washington UT-
511 PM MDT Fri Aug 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL WASHINGTON COUNTY WILL
EXPIRE AT 515 PM MDT...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. However small hail and heavy rain are still 
possible with this thunderstorm.

LAT...LON 3736 11362 3750 11343 3738 11335 3727 11343
TIME...MOT...LOC 2310Z 022DEG 17KT 3725 11351 

$$

AD

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 6:26 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Washington	114 min
Aug 13, 4:20 PM MDT	Severe Thunderstorm Warning	SLC	Iron, Washington	25 min
Aug 13, 5:14 PM MDT	Severe Thunderstorm Warning	SLC	Washington	16 min

Nearby

Severe Thunderstorm Warnings in Utah, 2021 Every 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.