Alert archive / South Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 917
The Storm Prediction Center issued this mesoscale discussion at Jun 10, 2021, 10:50 PM MDT for 11 counties in South Dakota. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Jun 10, 2021, 10:50 PM MDT (04:50 UTC)
- Expired
- Jun 11, 2021, 12:15 AM MDT
- In force
- 85 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 253
Counties Dewey County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Stanley County, SD, Sully County, SD, Ziebach County, SD
The radar
The Rapid City radar (KUDX), 103 km from the middle of the area, began a volume at 04:50 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, 4.8 hours before the alert went out and 108 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
- 1559 J/kg
- Mixed-layer CIN
- -71 J/kg
- Mixed-layer LCL
- 2700 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 88 m²/s²
- 0-3 km storm-relative helicity
- 177 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 15.0
The text
As transmitted.
283
ACUS11 KWNS 110451
SWOMCD
SPC MCD 110450
SDZ000-110615-
Mesoscale Discussion 0917
NWS Storm Prediction Center Norman OK
1150 PM CDT Thu Jun 10 2021
Areas affected...Western into central SD
Concerning...Severe Thunderstorm Watch 253...
Valid 110450Z - 110615Z
The severe weather threat for Severe Thunderstorm Watch 253
continues.
SUMMARY...A swath of significant severe wind appears increasingly
likely through 06Z.
DISCUSSION...A 78 mph wind gust was recently reported across
northwest SD, and a 72 mph gust with storms across southwest SD. In
addition, a cluster moving over the KUDX radar was producing 70-80
kt radar velocities at very low elevation above ground. With
additional strong updrafts noted across west-central SD, and a cold
front accelerating into the region, the potential for a swath of
significant severe wind should increase over the next 1-2 hours as
outflows continue to consolidate and stronger low-level flow near
and behind the cold front begins to catch up with ongoing
convection, within an environment of strong buoyancy and effective
shear.
..Dean.. 06/11/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...UNR...
LAT...LON 43320265 44030288 44550294 45290260 45510106 45470035
44580008 43590001 43510035 43370149 43320265SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 10, 7:28 PM MDT | Mesoscale Discussion | SPC | Bennett, Butte, Corson, Custer, Dewey, Fall River and 17 more | 92 min |
| Jun 10, 8:08 PM MDT | Severe Thunderstorm Watch | SPC | Bennett, Butte, Campbell, Corson, Custer, Dewey and 20 more | 6 hr |
| Jun 10, 10:07 PM MDT | Mesoscale Discussion | SPC | Bennett, Butte, Corson, Custer, Dewey, Fall River and 8 more | 83 min |
| Jun 10, 11:52 PM MDT | Mesoscale Discussion | SPC | Aurora, Beadle, Bon Homme, Brookings, Brown, Brule and 35 more | 53 min |
| Jun 11, 1:15 AM MDT | Severe Thunderstorm Watch | SPC | Aurora, Beadle, Bon Homme, Brookings, Brown, Brule and 34 more | 5 hr |
| Jun 11, 3:37 AM MDT | Mesoscale Discussion | SPC | Aurora, Beadle, Brookings, Brown, Charles Mix, Clark and 21 more | 83 min |
Nearby
Mesoscale Discussions in South 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.