Alert archive / Utah / Mesoscale Discussions in 2021

Mesoscale Discussion 1726

September 11, 20214 counties in Utah

The Storm Prediction Center issued this mesoscale discussion at Sep 11, 2021, 4:19 PM MDT for 4 counties in Utah. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Sep 11, 2021, 4:19 PM MDT (22:19 UTC)
Expired
Sep 11, 2021, 5:45 PM MDT
In force
86 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Box Elder County, UT, Davis County, UT, Juab County, UT, Tooele County, UT

The radar

The Salt Lake City radar (KMTX), 97 km from the middle of the area, began a volume at 22:22 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

Elko, NV (KLKN), launched 12:00Z, 10.3 hours before the alert went out and 92 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, Elko, NV at 12:00Z on 2021-09-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Elko, NV at 12:00Z on 2021-09-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 46 square meters per square second.193958Sfc1 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1278 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
46 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

895 
ACUS11 KWNS 112220
SWOMCD
SPC MCD 112219 
UTZ000-NVZ000-112345-

Mesoscale Discussion 1726
NWS Storm Prediction Center Norman OK
0519 PM CDT Sat Sep 11 2021

Areas affected...far eastern Nevada and portions of western Utah

Concerning...Severe potential...Watch unlikely 

Valid 112219Z - 112345Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated severe wind gusts are possible through the
afternoon and evening.

DISCUSSION...A cluster of storms has developed in eastern Nevada.
These storms are currently not particularly strong, but the airmass
downstream is unstable with MLCAPE around 500 J/kg per SPC
mesoanalysis. The sub-cloud layer is well-mixed and therefore,
sufficient evaporative cooling may occur for severe wind gusts in
the stronger downdrafts. SPC mesoanalysis also shows this region to
be favorable for downbursts with DCAPE around 1000 J/kg. However,
the airmass is not nearly as warm as yesterday where DCAPE was at or
above 1500 and severe wind gusts were more numerous. Therefore, an
isolated severe wind gust or two is possible this afternoon/evening,
but a more widespread threat is not anticipated.

..Bentley/Grams.. 09/11/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...SLC...LKN...

LAT...LON   40691438 41571373 41931314 41921274 41721234 41311201
            40821190 40031217 39441269 38781341 38771397 39971436
            40691438

Nearby

Mesoscale Discussions in Utah, 2021Every mesoscale discussion 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.