Alert archive / South Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 894
The Storm Prediction Center issued this mesoscale discussion at Jun 8, 2021, 10:41 PM MDT for Adams County, Grant County, North Dakota; 6 counties in South Dakota. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Jun 8, 2021, 10:41 PM MDT (04:41 UTC)
- Expired
- Jun 9, 2021, 12:15 AM MDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 248...249
Counties Adams County, ND, Grant County, ND, Corson County, SD, Dewey County, SD, Haakon County, SD, Jackson County, SD, Oglala Lakota County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 67 km from the middle of the area, began a volume at 04:44 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 00:00Z, 4.7 hours before the alert went out and 74 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
- 2269 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 2498 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 49 m²/s²
- 0-3 km storm-relative helicity
- 162 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 9.2
The text
As transmitted.
640
ACUS11 KWNS 090442
SWOMCD
SPC MCD 090441
SDZ000-NDZ000-090615-
Mesoscale Discussion 0894
NWS Storm Prediction Center Norman OK
1141 PM CDT Tue Jun 08 2021
Areas affected...Western Dakotas
Concerning...Severe Thunderstorm Watch 248...249...
Valid 090441Z - 090615Z
The severe weather threat for Severe Thunderstorm Watch 248, 249
continues.
SUMMARY...Gusty winds,along with some hail threat, will be noted
with a squall line as it propagates east over the next few hours.
New severe thunderstorm watch is not currently anticipated.
DISCUSSION...Linear MCS has evolved over the western Dakotas late
this evening in advance of a short-wave trough that is ejecting
northeast across eastern MT/WY. Over the last half hour or so, it
appears that an MCV may be forming over Perkins County SD, just
north of Prairie City. With an expanding precip shield in the wake
of the squall line, this activity should continue to progress east
at roughly 30kt. Gusty winds remain the primary threat but the
downstream air mass is not as buoyant and it would appear this
activity has peaked in intensity. At this time a new ww is not
anticipated.
..Darrow.. 06/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...BIS...UNR...
LAT...LON 43320328 44180240 44830211 46120260 46530141 44920074
43810131 43320222 43320328SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 8, 7:35 PM MDT | Mesoscale Discussion | SPC | Billings, Bowman, Burke, Divide, Dunn, Golden Valley and 4 more | 85 min |
| Jun 8, 6:37 PM MDT | Mesoscale Discussion | SPC | Butte, Custer, Fall River, Lawrence, Meade, Pennington | 83 min |
| Jun 8, 7:00 PM MDT | Severe Thunderstorm Watch | SPC | Butte, Custer, Fall River, Harding, Lawrence, Meade and 2 more | 5 hr |
| Jun 8, 8:50 PM MDT | Mesoscale Discussion | SPC | Butte, Custer, Harding, Lawrence, Meade, Pennington and 1 more | 85 min |
Nearby
Mesoscale Discussions in South Dakota, 2021Mesoscale Discussions in North Dakota, 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.