Alert archive / Idaho / Mesoscale Discussions in 2021

Mesoscale Discussion 131

February 26, 20214 counties in Idaho; Elko County, Nevada; Box Elder County, Utah

The Storm Prediction Center issued this mesoscale discussion at Feb 26, 2021, 3:30 PM MST for 4 counties in Idaho; Elko County, Nevada; Box Elder County, Utah. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Feb 26, 2021, 3:30 PM MST (22:30 UTC)
Expired: Feb 26, 2021, 5:30 PM MST
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Snow squall

Counties Bannock County, ID, Cassia County, ID, Oneida County, ID, Power County, ID, Elko County, NV, Box Elder County, UT

The radar

The Salt Lake City radar (KMTX), 141 km from the middle of the area, began a volume at 22:31 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, 10.5 hours before the alert went out and 90 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1346 m above ground
0-6 km bulk shear: 82 kt
0-1 km storm-relative helicity: 137 m²/s²
0-3 km storm-relative helicity: 233 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

638 
ACUS11 KWNS 262230
SWOMCD
SPC MCD 262230 
UTZ000-IDZ000-NVZ000-270030-

Mesoscale Discussion 0131
NWS Storm Prediction Center Norman OK
0430 PM CST Fri Feb 26 2021

Areas affected...Southeast ID...Northeast NV...Northern UT

Concerning...Snow Squall 

Valid 262230Z - 270030Z

SUMMARY...A snow squall producing brief blizzard-like conditions
should progress east-southeast before weakening after about 00-01Z.

DISCUSSION...Surface observations and radar reflectivity confirm the
presence of a snow squall along a cold front across a portion of the
Snake Valley in south-central ID extending west-southwest across
north-central NV. TWF measured a gust to 52 kt at 2141Z with less
than quarter-mile visibility in snow reported in the most recent
observation. JER also recorded a 35 kt gust at 2152Z with
quarter-mile visibility in snow. The snow squall is being supported
by a steep low-level lapse environment ahead of and along the front,
in addition to strong low-level northwesterlies behind the front per
time-series of CBX VWP data. Short-term guidance suggests this
strong flow regime is likely greatest now at peak heating and should
subside through the evening. 12Z HREF members and recent HRRR runs
that suggested the potential for a snow squall also indicate a
weakening trend to the squall after about 00-01Z. Until that time,
the squall may affect portions of the I-84 and I-15 corridors in ID
and far northern UT, and the I-80 corridor in NV.

..Grams.. 02/26/2021

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

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

LAT...LON   42851351 42971284 42811229 42481203 41861181 41411195
            41071266 40671383 40421510 40281643 40651717 40921752
            41271587 41851442 42311381 42851351

Nearby

Mesoscale Discussions in Idaho, 2021 Mesoscale Discussions in Nevada, 2021 Mesoscale Discussions in Utah, 2021 Every 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.