Alert archive / South Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 1606
The Storm Prediction Center issued this mesoscale discussion at Aug 26, 2021, 8:36 AM CDT for Big Stone County, Lac qui Parle County, Minnesota; 16 counties in South Dakota. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Aug 26, 2021, 8:36 AM CDT (13:36 UTC)
- Expired
- Aug 26, 2021, 10:00 AM CDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
Counties Big Stone County, MN, Lac qui Parle County, MN, Beadle County, SD, Brookings County, SD, Buffalo County, SD, Clark County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Grant County, SD, Hamlin County, SD, Hand County, SD, Jerauld County, SD, Kingsbury County, SD, Miner County, SD, Roberts County, SD, Sanborn County, SD, Spink County, SD
The radar
The Aberdeen radar (KABR), 107 km from the middle of the area, began a volume at 13:39 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Aberdeen, SD (KABR), launched 12:00Z, 1.6 hours before the alert went out and 55 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
- 1092 m above ground
- 0-6 km bulk shear
- 62 kt
- 0-1 km storm-relative helicity
- 365 m²/s²
- 0-3 km storm-relative helicity
- 490 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.4
The text
As transmitted.
935
ACUS11 KWNS 261337
SWOMCD
SPC MCD 261336
MNZ000-SDZ000-261500-
Mesoscale Discussion 1606
NWS Storm Prediction Center Norman OK
0836 AM CDT Thu Aug 26 2021
Areas affected...Eastern SD into extreme southwest MN
Concerning...Severe potential...Watch possible
Valid 261336Z - 261500Z
Probability of Watch Issuance...40 percent
SUMMARY...Sporadic strong-to-severe wind gusts will remain possible
this morning as a thunderstorm cluster moves southeastward. Watch
issuance is possible.
DISCUSSION...Sporadic strong to occasionally severe wind gusts have
been noted over the last 1-2 hours in association with a
thunderstorm cluster moving southeastward across eastern SD. This
convection is elevated and will likely remain so through the
morning, given rather substantial downstream MLCINH. However,
increasing low-level moisture transport may allow the cluster to
become rooted closer to the surface with time and allow it to tap
into larger MUCAPE (in excess of 2000 J/kg) as it tracks
southeastward.
Effective shear in excess of 40 kt will continue to support some
organization with this cluster, with a short-term severe wind threat
likely spreading into a larger portion of eastern SD and far
southwest MN. The longer-term evolution of this cluster remains
uncertain, due to potential stabilizing effects from a downstream
thunderstorm cluster across Iowa, but watch issuance is possible to
cover the threat through the late morning hours.
..Dean/Dial.. 08/26/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MPX...FSD...ABR...
LAT...LON 44569926 45089852 45599771 45709737 45609644 44969612
44669623 44349667 44079731 43869770 43789825 43829894
43889917 44079938 44569926SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 9:05 AM CDT | Severe Thunderstorm Watch | SPC | Big Stone, Chippewa, Kandiyohi, Lac qui Parle, Lincoln, Lyon and 11 more | 4 hr |
| Aug 26, 10:43 AM CDT | Mesoscale Discussion | SPC | Lac qui Parle, Lincoln, Lyon, Murray, Pipestone, Redwood and 1 more | 92 min |
| Aug 26, 1:12 PM CDT | Mesoscale Discussion | SPC | Fillmore, Houston, Winona | 93 min |
| Aug 26, 1:53 PM CDT | Mesoscale Discussion | SPC | Carver, Dakota, Goodhue, Hennepin, Le Sueur, Ramsey and 3 more | 97 min |
| Aug 26, 2:35 AM CDT | Mesoscale Discussion | SPC | Brown, Campbell, Corson, Dewey, Edmunds, Faulk and 6 more | 2 hr |
| Aug 26, 3:10 AM CDT | Mesoscale Discussion | SPC | Bon Homme, Charles Mix, Clay, Hutchinson, Turner, Yankton | 3 hr |
| Aug 26, 5:34 PM CDT | Mesoscale Discussion | SPC | Clay, Lincoln, Turner, Union, Yankton | 116 min |
Nearby
Mesoscale Discussions in South Dakota, 2021Mesoscale Discussions in Minnesota, 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.