Alert archive / Minnesota / Mesoscale Discussions in 2021
Mesoscale Discussion 1631
The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2021, 5:27 PM CDT for Emmet County, Iowa; 28 counties in Minnesota. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- Aug 28, 2021, 5:27 PM CDT (22:27 UTC)
- Expired
- Aug 28, 2021, 6:30 PM CDT
- In force
- 63 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 469
All 29 counties
Emmet County, IA, Blue Earth County, MN, Brown County, MN, Carver County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Goodhue County, MN, Jackson County, MN, Le Sueur County, MN, Lyon County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Pipestone County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Rock County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN
The radar
The Minneapolis radar (KMPX), 119 km from the middle of the area, began a volume at 22:31 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
Minneapolis, MN (KMPX), launched 12:00Z, 10.5 hours before the alert went out and 117 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
- 1550 J/kg
- Mixed-layer CIN
- -130 J/kg
- Mixed-layer LCL
- 676 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 139 m²/s²
- 0-3 km storm-relative helicity
- 193 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.3
The text
As transmitted.
513
ACUS11 KWNS 282227
SWOMCD
SPC MCD 282227
MNZ000-IAZ000-SDZ000-282330-
Mesoscale Discussion 1631
NWS Storm Prediction Center Norman OK
0527 PM CDT Sat Aug 28 2021
Areas affected...Southern Minnesota
Concerning...Tornado Watch 469...
Valid 282227Z - 282330Z
The severe weather threat for Tornado Watch 469 continues.
SUMMARY...A cluster of storms in southwestern Minnesota has shown
increasing damaging wind potential. The downstream environment
should continue to support organized convection. A downstream watch
is likely within the next hour or so.
DISCUSSION...A small cluster of thunderstorms has shown an increase
in the potential for strong wind gusts in southwest Minnesota. KFSD
velocity data show 60+ kts of outbound velocity in the lowest 1-2
km. This activity has had a history of QLCS tornadoes south of Sioux
Falls, SD. The environment ahead of the line is marginally
supportive of additional spin-ups along the leading edge of the
complex.
With the environment in southern Minnesota showing warming into the
low/mid 80s, buoyancy is increasing ahead of the line. An expected
increase in the low-level jet will also contribute to additional
low-level moistening this evening. This setup should favor
maintenance of the cluster for the next few hours. A downstream
watch is likely within the next hour or so.
..Wendt.. 08/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ARX...MPX...DMX...FSD...
LAT...LON 43899681 44379628 44779499 44849373 44699277 44189226
44109225 43679237 43509301 43359482 43519612 43619663
43899681SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 7:59 PM CDT | Mesoscale Discussion | SPC | Allamakee, Clayton, Fayette | 2 hr |
| Aug 27, 9:57 PM CDT | Mesoscale Discussion | SPC | Allamakee, Bremer, Chickasaw, Clayton, Fayette, Floyd and 3 more | 93 min |
| Aug 28, 2:43 PM CDT | Mesoscale Discussion | SPC | Lyon, Osceola, Plymouth, Sioux | 3 hr |
| Aug 28, 3:57 PM CDT | Severe Thunderstorm Watch | SPC | Lyon, O'Brien, Osceola, Plymouth, Sioux, Woodbury | 7 hr |
| Aug 28, 2:17 AM CDT | Mesoscale Discussion | SPC | Big Stone, Stevens, Swift, Traverse | 2 hr |
| Aug 28, 2:32 AM CDT | Severe Thunderstorm Watch | SPC | Big Stone, Traverse | 5 hr |
| Aug 28, 5:42 AM CDT | Mesoscale Discussion | SPC | Benton, Big Stone, Chippewa, Douglas, Grant, Kandiyohi and 11 more | 2 hr |
| Aug 28, 7:08 AM CDT | Severe Thunderstorm Watch | SPC | Big Stone, Chippewa, Douglas, Grant, Kandiyohi, Lac qui Parle and 13 more | 5 hr |
| Aug 28, 9:39 AM CDT | Mesoscale Discussion | SPC | Anoka, Benton, Chisago, Douglas, Grant, Isanti and 12 more | 2 hr |
| Aug 28, 10:34 AM CDT | Tornado Watch | SPC | Aitkin, Anoka, Benton, Carlton, Carver, Chisago and 14 more | 4 hr |
| Aug 28, 1:13 PM CDT | Mesoscale Discussion | SPC | Anoka, Chisago, Isanti, Kanabec, Pine | 2 hr |
| Aug 28, 3:44 PM CDT | Tornado Watch | SPC | Cottonwood, Jackson, Lincoln, Lyon, Murray, Nobles and 2 more | 5 hr |
| Aug 28, 5:59 PM CDT | Severe Thunderstorm Watch | SPC | Blue Earth, Brown, Carver, Faribault, Freeborn, Le Sueur and 11 more | 6 hr |
| Aug 28, 6:09 PM CDT | Mesoscale Discussion | SPC | Blue Earth, Brown, Cottonwood, Nicollet, Watonwan | 66 min |
Nearby
Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Iowa, 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.