Alert archive / Utah / Special Weather Statements in 2021

Special Weather Statement, NWS Salt Lake City, UT

August 21, 2021Duchesne County, Utah

NWS Salt Lake City, UT issued this special weather statement at Aug 21, 2021, 7:49 PM MDT for Duchesne County, Utah. It was in force for 41 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 21, 2021, 7:49 PM MDT (01:49 UTC)
Expired: Aug 21, 2021, 8:30 PM MDT
In force: 41 min
Issued by: NWS Salt Lake City, UT
Hail: 0.25 in
Wind: 55

County Duchesne County, UT

The radar

The Salt Lake City radar (KMTX), 194 km from the middle of the area, began a volume at 01:47 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, 1.8 hours before the alert went out and 130 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: 422 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 2862 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 171 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

315 
WWUS85 KSLC 220149
SPSSLC

Special Weather Statement
National Weather Service Salt Lake City UT
749 PM MDT Sat Aug 21 2021
 
UTZ112>114-220230-
Western Uinta Basin UT-Wasatch Plateau/Book Cliffs UT-
Western Uinta Mountains UT-
749 PM MDT Sat Aug 21 2021

...A strong thunderstorm will impact portions of central Duchesne
County through 830 PM MDT...

At 749 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles southeast of Tabiona, or 14 miles west of Duchesne, moving
northeast at 50 mph.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail. 

SOURCE...Radar indicated. 

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects. Minor damage to outdoor objects is 
         possible. 

Locations impacted include...
Tabiona, Altonah, Moon Lake, Mountain Home, Utahn and Talmage. 

This includes the following highways...
 US Route 40 between mile markers 63 and 79.
 Utah Route 35 between mile markers 39 and 59.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

&&

LAT...LON 4011 11062 4019 11084 4075 11061 4067 10998
      4062 10997
TIME...MOT...LOC 0149Z 219DEG 45KT 4025 11064 

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

$$

Webber

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 21, 6:06 PM MDT	Severe Thunderstorm Warning Considerable damage threat	SLC	Box Elder, Cache, Davis, Morgan, Rich, Salt Lake and 3 more	39 min
Aug 21, 6:29 PM MDT	Severe Thunderstorm Warning	SLC	Cache, Rich	61 min
Aug 21, 6:40 PM MDT	Severe Thunderstorm Warning Considerable damage threat	SLC	Box Elder, Cache, Davis, Morgan, Rich, Salt Lake and 3 more	50 min
Aug 21, 6:59 PM MDT	Areal Flood Advisory	SLC	Davis, Weber	2 hr
Aug 21, 7:08 PM MDT	Severe Thunderstorm Warning Considerable damage threat	SLC	Summit	37 min
Aug 21, 7:23 PM MDT	Special Weather Statement	SLC	Salt Lake	37 min
Aug 21, 7:33 PM MDT	Areal Flood Advisory	SLC	Davis, Morgan, Salt Lake, Summit	117 min
Aug 21, 7:41 PM MDT	Special Weather Statement	SLC	Summit	49 min
Aug 21, 8:09 PM MDT	Special Weather Statement	SLC	Summit	51 min
Aug 21, 8:14 PM MDT	Special Weather Statement	SLC		31 min
Aug 21, 8:19 PM MDT	Severe Thunderstorm Warning	SLC	Duchesne, Summit	26 min
Aug 21, 8:32 PM MDT	High Wind Warning	SLC	Utah	3 hr
Aug 21, 9:59 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Salt Lake	91 min
Aug 21, 7:45 PM MDT	Severe Thunderstorm Warning Destructive damage threat	SLC	Uinta	30 min
Aug 21, 8:07 PM MDT	Special Weather Statement	SLC	Uinta	38 min
Aug 21, 9:16 PM MDT	Special Weather Statement	SLC	Uinta	44 min

Nearby

Special Weather Statements in Utah, 2021 Every special weather statement 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.