Alert archive / Minnesota / Mesoscale Discussions in 2021
Mesoscale Discussion 1358
The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2021, 7:12 PM CDT for 7 counties in Minnesota; 6 counties in Wisconsin. It was in force for 93 min.
The area
The outline as issued.
The facts
- Issued
- Jul 26, 2021, 7:12 PM CDT (00:12 UTC)
- Expired
- Jul 26, 2021, 8:45 PM CDT
- In force
- 93 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 393
Counties Aitkin County, MN, Carlton County, MN, Cass County, MN, Crow Wing County, MN, Kanabec County, MN, Mille Lacs County, MN, Pine County, MN, Ashland County, WI, Bayfield County, WI, Burnett County, WI, Douglas County, WI, Sawyer County, WI, Washburn County, WI
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
International Fa, MN (KINL), launched 00:00Z, 0.2 hours before the alert went out and 208 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
- 2004 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- 108 m²/s²
- 0-3 km storm-relative helicity
- 306 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
208
ACUS11 KWNS 270012
SWOMCD
SPC MCD 270012
WIZ000-MNZ000-270145-
Mesoscale Discussion 1358
NWS Storm Prediction Center Norman OK
0712 PM CDT Mon Jul 26 2021
Areas affected...Northeast MN into northwest WI
Concerning...Severe Thunderstorm Watch 393...
Valid 270012Z - 270145Z
The severe weather threat for Severe Thunderstorm Watch 393
continues.
SUMMARY...The threat for very large hail and locally damaging wind
continues with ongoing supercell cluster across northeast MN. This
cluster will likely spread into northwest WI, where new watch
issuance is likely by 01Z.
DISCUSSION...At 00Z, an intense thunderstorm cluster with embedded
supercells is ongoing across northeast MN. The strongest cell within
this cluster earlier produced baseball-size hail, damaging wind, and
a tornado across northern MN. MLCAPE in excess of 1500 J/kg and
effective shear of 40-50 kt will continue to support supercell
structures as the cluster spreads southeastward, with renewed
development possible along the southwestern flank as the low-level
jet gradually increases this evening.
Some uncertainty remains regarding whether this cluster will evolve
into a forward propagating MCS, or persist as a supercell cluster.
In either case, a significant hail and wind threat is expected to
spread into northwest WI this evening, with a tornado or two also
possible if the supercell mode is maintained. A new severe
thunderstorm watch will likely be issued for northwest WI by 01Z.
..Dean/Grams.. 07/27/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DLH...MPX...
LAT...LON 47239444 47549316 47529205 47349131 47139072 46369045
45779022 45809189 45839353 46159444 47229464 47239444SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 26, 7:40 PM CDT | Mesoscale Discussion | SPC | Becker, Big Stone, Clay, Douglas, Grant, Otter Tail and 6 more | 95 min |
| Jul 26, 8:41 PM CDT | Mesoscale Discussion | SPC | Carlton, Pine | 94 min |
| Jul 27, 4:00 AM CDT | Mesoscale Discussion | SPC | Anoka, Benton, Carver, Chisago, Dakota, Hennepin and 11 more | 3 hr |
| Jul 27, 7:48 AM CDT | Mesoscale Discussion | SPC | Houston | 117 min |
| Jul 26, 7:25 PM CDT | Severe Thunderstorm Watch | SPC | Ashland, Bayfield, Burnett, Douglas, Iron, Price and 2 more | 3 hr |
| Jul 26, 11:50 PM CDT | Mesoscale Discussion | SPC | Bayfield, Brown, Calumet, Door, Douglas, Fond du Lac and 20 more | 55 min |
Nearby
Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Wisconsin, 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.