Alert archive / Minnesota / Mesoscale Discussions in 2021
Mesoscale Discussion 990
The Storm Prediction Center issued this mesoscale discussion at Jun 17, 2021, 7:02 PM CDT for 6 counties in Iowa; 17 counties in Minnesota; 17 counties in Wisconsin. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Jun 17, 2021, 7:02 PM CDT (00:02 UTC)
- Expired
- Jun 17, 2021, 8:30 PM CDT
- In force
- 88 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 276
All 40 counties
Allamakee County, IA, Howard County, IA, Mitchell County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Blue Earth County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Le Sueur County, MN, Mower County, MN, Nicollet County, MN, Olmsted County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Winona County, MN, Adams County, WI, Buffalo County, WI, Clark County, WI, Eau Claire County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Marathon County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Portage County, WI, Richland County, WI, Trempealeau County, WI, Vernon County, WI, Waushara County, WI, Wood County, WI
The radar
The La Crosse radar (KARX), 55 km from the middle of the area, began a volume at 00:02 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 00:00Z, 0.0 hours before the alert went out and 170 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
- 61 J/kg
- Mixed-layer CIN
- -387 J/kg
- Mixed-layer LCL
- 1555 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- -13 m²/s²
- 0-3 km storm-relative helicity
- 56 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
623
ACUS11 KWNS 180002
SWOMCD
SPC MCD 180002
WIZ000-IAZ000-MNZ000-180130-
Mesoscale Discussion 0990
NWS Storm Prediction Center Norman OK
0702 PM CDT Thu Jun 17 2021
Areas affected...South-Central/Southeast MN...West-Central
WI...North-Central/Northeast IA
Concerning...Severe Thunderstorm Watch 276...
Valid 180002Z - 180130Z
The severe weather threat for Severe Thunderstorm Watch 276
continues.
SUMMARY...The threat for severe thunderstorms continues across much
of the Upper MS Valley. Large hail is the primary threat, with some
damaging wind gusts possible as well. Parts of
south-central/southeast MN are being monitored for additional watch
issuance.
DISCUSSION...Recent surface analysis places the cold front from
about 10 miles east-southeast of EAU southwestward through
south-central MN and far northwest IA. A corridor of slightly higher
dewpoints exists along this frontal boundary, with mid 60s dewpoints
extending into far west-central WI. A few storms have developed
along this front in far west-central WI, where surface temperatures
were a few degrees higher, which resulted in less convective
inhibition. Environment near these storms supports strong updrafts
and the potential for quick upscale growth on storm outflow. Severe
threat with these storms will likely persist into more of central
WI.
Farther west (across southwest MN), a few storms have recently
developed, likely as a result of persistent warm air advection
across the region. Character of the reflectivity also suggests thee
storms are elevated. Steep mid-level lapse rates and resulting
strong buoyancy could result in a few updrafts capable of producing
large hail. Some additional development appears possible across this
area with new echos now beginning to appear. Overall storm coverage
remains uncertain given the warm low to mid-level temperatures and
resulting convective inhibition. However, persistent isentropic
ascent coupled with the approach of a subtle vorticity maximum and
southward pushing 850mb front suggest potential for additional
storms.
..Mosier/Guyer.. 06/18/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GRB...MKX...ARX...MPX...DMX...
LAT...LON 44449451 44889213 45038995 44738908 44158899 43389005
43209213 43249378 44449451SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 17, 9:01 PM CDT | Mesoscale Discussion | SPC | Allamakee, Howard, Mitchell, Winneshiek | 89 min |
| Jun 17, 10:01 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 10 more | 6 hr |
| Jun 17, 10:52 PM CDT | Mesoscale Discussion | SPC | Allamakee, Howard, Winneshiek | 83 min |
| Jun 18, 1:34 AM CDT | Mesoscale Discussion | SPC | Allamakee | 116 min |
| Jun 17, 7:22 PM CDT | Severe Thunderstorm Watch | SPC | Blue Earth, Brown, Dakota, Faribault, Freeborn, Goodhue and 9 more | 4 hr |
| Jun 18, 5:03 PM CDT | Mesoscale Discussion | SPC | Becker, Beltrami, Cass, Clay, Clearwater, Crow Wing and 9 more | 87 min |
Nearby
Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Wisconsin, 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.