Alert archive / Nevada / Mesoscale Discussions in 2021

Mesoscale Discussion 1415

August 1, 2021Elko County, Lincoln County, White Pine County, Nevada; Beaver County, Iron County, Millard County, Utah

The Storm Prediction Center issued this mesoscale discussion at Aug 1, 2021, 11:24 AM PDT for Elko County, Lincoln County, White Pine County, Nevada; Beaver County, Iron County, Millard County, Utah. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued
Aug 1, 2021, 11:24 AM PDT (18:24 UTC)
Expired
Aug 1, 2021, 1:00 PM PDT
In force
96 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Elko County, NV, Lincoln County, NV, White Pine County, NV, Beaver County, UT, Iron County, UT, Millard County, UT

The radar

The Cedar City radar (KICX), 164 km from the middle of the area, began a volume at 18:25 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, 6.4 hours before the alert went out and 260 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 2021-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 680 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, Las Vegas, NV at 12:00Z on 2021-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 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
680 J/kg
Mixed-layer CIN
-99 J/kg
Mixed-layer LCL
1983 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
27 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

091 
ACUS11 KWNS 011824
SWOMCD
SPC MCD 011824 
UTZ000-AZZ000-NVZ000-012000-

Mesoscale Discussion 1415
NWS Storm Prediction Center Norman OK
0124 PM CDT Sun Aug 01 2021

Areas affected...portions of eastern Nevada into western Utah

Concerning...Severe potential...Watch unlikely 

Valid 011824Z - 012000Z

Probability of Watch Issuance...5 percent

SUMMARY...A couple damaging gusts may occur in association with the
stronger wet downbursts. A WW issuance is not expected.

DISCUSSION...Thunderstorms are gradually increasing in coverage and
intensity this afternoon as convective temperatures are locally
being exceeded. Latest METAR observations show surface temperatures
climbing into the 80s across parts of the Great Basin into the Lower
Colorado River Valley as mostly clear skies (evident via visible
satellite) are allowing the boundary layer to destabilize. 18Z
mesoanalysis shows 7-8.5 C/km 0-3km lapse rates and 500-1000 J/kg
MLCAPE already in place, and with continued surface heating, up to 9
C/km low-level lapse rates and over 1000 J/kg MLCAPE may become
achievable on a widespread basis. 

Deep-layer vertical shear is lacking, suggesting that storm mode
should be short-lived single/multi-cellular. However, given
1.00-1.25 inch precipitable water values and aforementioned steep
low-level lapse rates in place, a couple of the more robust storms
(albeit brief) may support heavy enough storm cores to induce brief
but damaging (potentially severe) wind gusts through the afternoon.
Nonetheless, given the sparse and short-lived nature of the severe
threat, a WW issuance is not anticipated.

..Squitieri/Grams.. 08/01/2021

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

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

LAT...LON   36591538 39271589 41231545 41451453 41021348 39561295
            38621289 37561321 37061378 36751422 36371484 36591538

Nearby

Mesoscale Discussions in Nevada, 2021Mesoscale 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.