Alert archive / Nebraska / Mesoscale Discussions in 2021

Mesoscale Discussion 176

March 14, 202110 counties in Nebraska; 8 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Mar 14, 2021, 11:40 AM MDT for 10 counties in Nebraska; 8 counties in South Dakota. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Mar 14, 2021, 11:40 AM MDT (17:40 UTC)
Expired: Mar 14, 2021, 3:45 PM MDT
In force: 4 hr
Issued by: the Storm Prediction Center
Concerning: Blizzard

Counties Box Butte County, NE, Brown County, NE, Cherry County, NE, Dawes County, NE, Grant County, NE, Keya Paha County, NE, Morrill County, NE, Scotts Bluff County, NE, Sheridan County, NE, Sioux County, NE, Bennett County, SD, Custer County, SD, Fall River County, SD, Jackson County, SD, Mellette County, SD, Oglala Lakota County, SD, Todd County, SD, Tripp County, SD

The radar

The North Platte radar (KLNX), 130 km from the middle of the area, began a volume at 17:39 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

Rapid City, SD (KUNR), launched 12:00Z, 5.7 hours before the alert went out and 174 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: 1271 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 131 m²/s²
0-3 km storm-relative helicity: 270 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

983 
ACUS11 KWNS 141740
SWOMCD
SPC MCD 141740 
NEZ000-SDZ000-142145-

Mesoscale Discussion 0176
NWS Storm Prediction Center Norman OK
1240 PM CDT Sun Mar 14 2021

Areas affected...Northwest Nebraska and southwest South Dakota

Concerning...Blizzard 

Valid 141740Z - 142145Z

SUMMARY...Heavy snow and blizzard conditions are expected through
the afternoon.

DISCUSSION...Snowfall rates have increased substantially across
northwest Nebraska and southwest South Dakota over the last hour.
Expect snowfall rates to continue to increase and persist through
the afternoon as strong 700mb warm air advection continues across
the region. In addition to the very heavy snowfall rates,
blizzard/near blizzard conditions are ongoing across the region.
Winds are around 25 to 30 knots with gusts 35 to 45 knots.
Visibilities are currently 1/4 mi and 1/2 mi across northwest
Nebraska and southwest South Dakota, but less than 1/4 mi visibility
is likely in the next few hours. South central South Dakota/north
central Nebraska currently have temperatures in the upper 30s with
rain, but rain should change to snow across these areas in the next
few hours as cooler temperatures aloft move eastward.

..Bentley.. 03/14/2021

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

ATTN...WFO...FSD...ABR...LBF...UNR...CYS...

LAT...LON   43470402 43830357 44030222 43790068 43679966 43269933
            42809921 42429938 42100043 41910124 41810170 41710222
            41700289 41700370 42050402 43470402

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 13, 7:15 PM MST	Mesoscale Discussion	SPC	Banner, Kimball, Scotts Bluff, Sioux	6 hr
Mar 13, 7:39 PM MST	Mesoscale Discussion	SPC	Banner, Kimball, Scotts Bluff, Sioux	6 hr
Mar 14, 1:55 AM MST	Mesoscale Discussion	SPC	Banner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 3 more	6 hr
Mar 14, 9:21 AM MDT	Mesoscale Discussion	SPC	Banner, Box Butte, Cheyenne, Kimball, Morrill, Scotts Bluff	4 hr
Mar 14, 5:20 PM MDT	Mesoscale Discussion	SPC	Boyd, Burt, Cedar, Dakota, Dixon, Keya Paha and 3 more	6 hr

Nearby

Mesoscale Discussions in Nebraska, 2021 Mesoscale Discussions in South Dakota, 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.