Alert archive / Minnesota / Mesoscale Discussions in 2021
Mesoscale Discussion 1359
The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2021, 7:40 PM CDT for 12 counties in Minnesota; 10 counties in North Dakota; 7 counties in South Dakota. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- Jul 26, 2021, 7:40 PM CDT (00:40 UTC)
- Expired
- Jul 26, 2021, 9:15 PM CDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 393
All 29 counties
Becker County, MN, Big Stone County, MN, Clay County, MN, Douglas County, MN, Grant County, MN, Otter Tail County, MN, Pope County, MN, Stevens County, MN, Todd County, MN, Traverse County, MN, Wadena County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Dickey County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Stutsman County, ND, Brown County, SD, Campbell County, SD, Day County, SD, Edmunds County, SD, Marshall County, SD, McPherson County, SD, Roberts County, SD
The radar
The Aberdeen radar (KABR), 129 km from the middle of the area, began a volume at 00:43 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
Aberdeen, SD (KABR), launched 00:00Z, 0.7 hours before the alert went out and 175 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
- 3005 J/kg
- Mixed-layer CIN
- -57 J/kg
- Mixed-layer LCL
- 1765 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 189 m²/s²
- 0-3 km storm-relative helicity
- 262 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 25.5
The text
As transmitted.
818
ACUS11 KWNS 270040
SWOMCD
SPC MCD 270040
MNZ000-SDZ000-NDZ000-270215-
Mesoscale Discussion 1359
NWS Storm Prediction Center Norman OK
0740 PM CDT Mon Jul 26 2021
Areas affected...Southeast North Dakota...far northeast South
Dakota...and western Minnesota
Concerning...Severe Thunderstorm Watch 393...
Valid 270040Z - 270215Z
The severe weather threat for Severe Thunderstorm Watch 393
continues.
SUMMARY...The severe weather threat may be waning in the western
half of watch 393.
DISCUSSION...At least one supercell formed along the surface front
in central North Dakota, but any additional attempts struggled. In
the last 30 minutes this supercell has weakened and is now gone.
Additional convection is trying to form along the front, but
considering the history of the recent supercell which was able to
seemingly reach maturity during peak surface instability, the chance
for additional storms may be waning, especially as the boundary
layer begins to cool. The primary low-level jet axis is east of this
area with any additional isentropic ascent expected to be focused
across eastern Minnesota and northern Wisconsin. Therefore, without
any additional sources for ascent, the window for severe storms
across the western half of watch 393 is waning. Trends will continue
to be monitored for another hour or two, but portions of watch 393
may be cancelled early if a lack of severe storms becomes
increasingly obvious.
..Bentley/Dean.. 07/27/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DLH...MPX...FGF...ABR...BIS...
LAT...LON 46780009 47209818 47229568 46939474 46609443 46039444
45889457 45589524 45269677 45079854 45299960 45800012
46780009SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 26, 7:12 PM CDT | Mesoscale Discussion | SPC | Aitkin, Carlton, Cass, Crow Wing, Kanabec, Mille Lacs and 1 more | 93 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 |
Nearby
Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in North Dakota, 2021Mesoscale Discussions in South Dakota, 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.