Alert archive / Minnesota / Mesoscale Discussions in 2021
Mesoscale Discussion 1371
The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2021, 2:48 AM CDT for 18 counties in Minnesota; Ransom County, Richland County, Sargent County, North Dakota; 6 counties in South Dakota. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 28, 2021, 2:48 AM CDT (07:48 UTC)
- Expired
- Jul 28, 2021, 5:15 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 27 counties
Big Stone County, MN, Chippewa County, MN, Douglas County, MN, Grant County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Meeker County, MN, Pope County, MN, Redwood County, MN, Renville County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Traverse County, MN, Wilkin County, MN, Yellow Medicine County, MN, Ransom County, ND, Richland County, ND, Sargent County, ND, Codington County, SD, Day County, SD, Deuel County, SD, Grant County, SD, Marshall County, SD, Roberts County, SD
The radar
The Aberdeen radar (KABR), 168 km from the middle of the area, began a volume at 07:49 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, 7.8 hours before the alert went out and 179 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
- 3728 J/kg
- Mixed-layer CIN
- -131 J/kg
- Mixed-layer LCL
- 1430 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 65 m²/s²
- 0-3 km storm-relative helicity
- 256 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 7.9
The text
As transmitted.
326
ACUS11 KWNS 280748
SWOMCD
SPC MCD 280748
MNZ000-SDZ000-NDZ000-281015-
Mesoscale Discussion 1371
NWS Storm Prediction Center Norman OK
0248 AM CDT Wed Jul 28 2021
Areas affected...Portions of far southeastern ND...far northeastern
SD...and western/central MN
Concerning...Severe potential...Watch unlikely
Valid 280748Z - 281015Z
Probability of Watch Issuance...20 percent
SUMMARY...Storms capable of producing mainly isolated large hail may
develop through the early morning hours. Watch issuance appears
unlikely at this time.
DISCUSSION...A minor mid-level disturbance over the northern Plains
appears to be rounding the apex of the upper high centered over the
central Plains early this morning. This perturbation, coupled with a
strengthening south-southwesterly low-level jet over the northern
Plains per recent mesoanalysis and area VWPs, is likely contributing
to the uptick in convection across the far eastern Dakotas. The 00Z
sounding from ABR sampled steep mid-level lapse rates (8.3 C/km in
the 700-500-mb layer) atop a rich low-level airmass. Resultant
instability remains very strong early this morning across the
northern Plains into the Upper Midwest, with MUCAPE of 3500-4500
J/kg present in a fairly narrow corridor extending from eastern ND
to southern MN. The flow across this region veers from around 30-35
kt of southwesterly low-level winds to west-northwesterly while
slowly strengthening at mid/upper levels. Related favorable
deep-layer shear of 40-50+ kt should prove favorable for updraft
organization. An elevated supercell or two appears possible in this
favorable environment, mainly posing a threat for isolated large
hail. Even with some convective inhibition, strong to locally severe
wind gusts may also occur given the large amount of instability
present. At this point, the overall severe threat is expected to
remain fairly isolated owing to the modest large-scale ascent aloft.
While convective and observational trends will be closely monitored
though the early morning, a watch currently appears unlikely.
..Gleason/Edwards.. 07/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MPX...FGF...FSD...ABR...
LAT...LON 44379647 45479787 46699775 46909742 46619608 45639446
44819445 44289540 44379647SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 27, 7:33 PM CDT | Mesoscale Discussion | SPC | Dakota, Dodge, Fillmore, Freeborn, Goodhue, Houston and 8 more | 87 min |
| Jul 27, 8:03 PM CDT | Severe Thunderstorm Watch | SPC | Dakota, Dodge, Fillmore, Freeborn, Goodhue, Houston and 8 more | 6 hr |
| Jul 27, 10:35 PM CDT | Mesoscale Discussion | SPC | Dodge, Fillmore, Houston, Mower, Olmsted, Winona | 55 min |
| Jul 28, 10:28 AM CDT | Mesoscale Discussion | SPC | Aitkin, Beltrami, Cass, Clearwater, Hubbard, Itasca | 2 hr |
| Jul 28, 12:59 PM CDT | Mesoscale Discussion | SPC | Koochiching, Lake, Lake of the Woods, Saint Louis | 2 hr |
| Jul 28, 3:32 PM CDT | Mesoscale Discussion | SPC | Beltrami, Clearwater, Lake of the Woods, Mahnomen, Red Lake | 118 min |
| Jul 28, 5:09 PM CDT | Mesoscale Discussion | SPC | Aitkin, Anoka, Benton, Carlton, Chisago, Crow Wing and 7 more | 2 hr |
Nearby
Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in South Dakota, 2021Mesoscale Discussions in North 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.