Alert archive / South Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 1976
The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 9:10 AM CST for Boyd County, Keya Paha County, Nebraska; 17 counties in South Dakota. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 10, 2021, 9:10 AM CST (15:10 UTC)
- Expired
- Dec 10, 2021, 1:15 PM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Heavy snow
Counties Boyd County, NE, Keya Paha County, NE, Aurora County, SD, Bon Homme County, SD, Brule County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Lake County, SD, McCook County, SD, Miner County, SD, Sanborn County, SD, Todd County, SD, Tripp County, SD, Turner County, SD, Yankton County, SD
The radar
The North Platte radar (KLNX), 166 km from the middle of the area, began a volume at 15:13 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
Aberdeen, SD (KABR), launched 12:00Z, 3.2 hours before the alert went out and 206 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2000 m above ground
- 0-6 km bulk shear
- 79 kt
- 0-1 km storm-relative helicity
- -67 m²/s²
- 0-3 km storm-relative helicity
- -9 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
257
ACUS11 KWNS 101510
SWOMCD
SPC MCD 101510
SDZ000-NEZ000-101915-
Mesoscale Discussion 1976
NWS Storm Prediction Center Norman OK
0910 AM CST Fri Dec 10 2021
Areas affected...Far North-Central NE...South-Central into
Southeast/East-Central SD
Concerning...Heavy snow
Valid 101510Z - 101915Z
SUMMARY...Increasing snowfall rates are expected from north-central
NE into east-central SD over the next few hours.
DISCUSSION...Regional radar imagery currently depicts a band of
moderate snow from north-central NE/south-central SD northeastward
into portions of east-central SD. This snow band is expected to
become a bit more organized over the next few hours as both the
surface low (over the central High Plains) and associated
low/mid-level low move northeastward. At the same time, warm-air
advection throughout the northeastward periphery of the surface low
will strengthen, with the associated ascent contributing to
increased snowfall rates. Predominantly moderate snowfall is
anticipated over the next few hours, with rates occasionally
exceeding 1" per hour.
..Mosier.. 12/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FSD...OAX...ABR...LBF...UNR...
LAT...LON 42490073 42950147 43560080 44039896 44119666 43019731
42490073SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 9, 9:49 PM CST | Mesoscale Discussion | SPC | Box Butte, Brown, Cherry, Dawes, Keya Paha, Rock and 2 more | 5 hr |
| Dec 10, 2:39 AM CST | Mesoscale Discussion | SPC | Bennett, Custer, Fall River, Jackson, Mellette, Oglala Lakota and 2 more | 4 hr |
| Dec 10, 12:27 PM CST | Mesoscale Discussion | SPC | Bon Homme, Clay, Hanson, Hutchinson, Lake, Lincoln and 6 more | 4 hr |
Nearby
Mesoscale Discussions in South Dakota, 2021Mesoscale Discussions in Nebraska, 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.