Alert archive / Wisconsin / Mesoscale Discussions in 2021
Mesoscale Discussion 1590
The Storm Prediction Center issued this mesoscale discussion at Aug 24, 2021, 7:10 AM CDT for 19 counties in Minnesota; 21 counties in Wisconsin. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- Aug 24, 2021, 7:10 AM CDT (12:10 UTC)
- Expired
- Aug 24, 2021, 8:45 AM CDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 460
All 40 counties
Blue Earth County, MN, Chisago County, MN, Dakota County, MN, Dodge County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Le Sueur County, MN, Mower County, MN, Olmsted County, MN, Ramsey County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Winona County, MN, Adams County, WI, Barron County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn 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, Polk County, WI, Portage County, WI, Saint Croix County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Wood County, WI
The radar
The Minneapolis radar (KMPX), 102 km from the middle of the area, began a volume at 12:10 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
Minneapolis, MN (KMPX), launched 12:00Z, 0.2 hours before the alert went out and 105 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
- 1192 J/kg
- Mixed-layer CIN
- -180 J/kg
- Mixed-layer LCL
- 1234 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 141 m²/s²
- 0-3 km storm-relative helicity
- 178 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.9
The text
As transmitted.
286
ACUS11 KWNS 241211
SWOMCD
SPC MCD 241210
WIZ000-MNZ000-241345-
Mesoscale Discussion 1590
NWS Storm Prediction Center Norman OK
0710 AM CDT Tue Aug 24 2021
Areas affected...Portions of southern/eastern MN into
western/central WI
Concerning...Severe Thunderstorm Watch 460...
Valid 241210Z - 241345Z
The severe weather threat for Severe Thunderstorm Watch 460
continues.
SUMMARY...Strong to severe wind gusts may continue this morning with
multiple clusters of storms. The need for a downstream Severe
Thunderstorm Watch is uncertain.
DISCUSSION...The primary MCS across central/eastern MN has produced
mainly sub-severe measured wind gusts as it moved over the Twin
Cities metro, likely owing to a shallow near-surface stable layer
evident on the 12Z sounding from MPX. Still, velocity data from KMPX
show strong outbound velocities at low levels, and the environment
downstream should remain at least somewhat conducive for
strong/gusty winds capable of producing occasional damage in the
short term. Another cluster of storms has developed across
west-central WI along and just north of the surface boundary. A
measured severe wind gust to 55 kt was reported at KEAU at 1145Z
with this lead cluster. The need for a downstream Severe
Thunderstorm Watch into more of southern MN and central WI remains
unclear, but convective trends will continue to be closely
monitored.
..Gleason/Thompson.. 08/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GRB...MKX...ARX...MPX...
LAT...LON 44229470 44439370 44889313 45549307 45599179 45339065
44968937 43678946 43539024 43579301 43939469 44229470SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 24, 1:10 AM CDT | Mesoscale Discussion | SPC | Anoka, Benton, Carver, Chippewa, Dakota, Douglas and 26 more | 95 min |
| Aug 24, 2:17 AM CDT | Severe Thunderstorm Watch | SPC | Anoka, Benton, Big Stone, Brown, Carver, Chippewa and 34 more | 7 hr |
| Aug 24, 3:00 AM CDT | Mesoscale Discussion | SPC | Anoka, Benton, Big Stone, Brown, Carver, Chippewa and 35 more | 2 hr |
| Aug 24, 5:00 AM CDT | Mesoscale Discussion | SPC | Anoka, Carver, Dakota, Hennepin, Kandiyohi, McLeod and 8 more | 90 min |
| Aug 24, 6:00 AM CDT | Mesoscale Discussion | SPC | Dodge, Faribault, Fillmore, Freeborn, Houston, Mower and 5 more | 90 min |
| Aug 24, 12:44 PM CDT | Mesoscale Discussion | SPC | Houston | 91 min |
| Aug 24, 9:13 AM CDT | Mesoscale Discussion | SPC | Brown, Calumet, Menominee, Oconto, Outagamie, Shawano and 3 more | 62 min |
| Aug 24, 1:52 PM CDT | Severe Thunderstorm Watch | SPC | Grant | 5 hr |
| Aug 24, 3:09 PM CDT | Mesoscale Discussion | SPC | Green, Rock, Walworth | 66 min |
| Aug 24, 3:55 PM CDT | Severe Thunderstorm Watch | SPC | Green, Lafayette, Rock, Walworth | 5 hr |
Nearby
Mesoscale Discussions in Wisconsin, 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.