Alert archive / North Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 1576
The Storm Prediction Center issued this mesoscale discussion at Aug 22, 2021, 2:21 PM CDT for 15 counties in North Dakota; 14 counties in South Dakota. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 22, 2021, 2:21 PM CDT (19:21 UTC)
- Expired
- Aug 22, 2021, 4:45 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 29 counties
Benson County, ND, Burleigh County, ND, Dickey County, ND, Eddy County, ND, Emmons County, ND, Foster County, ND, Kidder County, ND, LaMoure County, ND, Logan County, ND, McHenry County, ND, McIntosh County, ND, Pierce County, ND, Sheridan County, ND, Stutsman County, ND, Wells County, ND, Beadle County, SD, Brown County, SD, Buffalo County, SD, Campbell County, SD, Edmunds County, SD, Faulk County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jerauld County, SD, McPherson County, SD, Potter County, SD, Spink County, SD, Walworth County, SD
The radar
The Aberdeen radar (KABR), 95 km from the middle of the area, began a volume at 19:24 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
Bismarck Municip, ND (KBIS), launched 12:00Z, 7.4 hours before the alert went out and 135 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
- 1536 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 311 m²/s²
- 0-3 km storm-relative helicity
- 445 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
001
ACUS11 KWNS 221922
SWOMCD
SPC MCD 221921
SDZ000-NDZ000-222145-
Mesoscale Discussion 1576
NWS Storm Prediction Center Norman OK
0221 PM CDT Sun Aug 22 2021
Areas affected...the east-central Dakotas
Concerning...Severe potential...Watch likely
Valid 221921Z - 222145Z
Probability of Watch Issuance...80 percent
SUMMARY...Storms will likely form by 21Z, with severe hail or a
tornado possible as they mature across the Dakotas.
DISCUSSION...Surface analysis shows a low over north-central ND,
with a developing cold front extending south/southwestward into
western SD, and a dryline from near BIS to PIR. A diffuse warm front
extends east from the low across ND, where pockets of heating and
low-level warm advection are helping to slowly destabilize the air
mass.
Moisture quality is a concern across the region, but cooling aloft
as well as strong lift along the front will likely result in a few
severe storms after 20-21Z. Wind profiles are favorable or
supercells with deep-layer shear around 50 kt and increasing SRH.
Given drying behind the cold front, and relatively coolness
currently over the eastern Dakotas, only a narrow ribbon of
surface-based/effective SRH is expected to exist immediately ahead
of the front. Tornado potential is heavily dependent on
boundary-layer moisture quality, but the overall supercell setup
appears favorable. As such, a watch will likely be needed. Large
hail will be a distinct threat given expected storm mode as well as
cool temperatures aloft.
..Jewell/Kerr.. 08/22/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...FSD...ABR...BIS...
LAT...LON 44579784 44349804 43929866 43879940 44099996 45680020
46480036 47330073 47940091 48310090 48600020 48169884
47579829 46359794 45529781 44579784SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 22, 3:36 PM CDT | Severe Thunderstorm Watch | SPC | Barnes, Benson, Bottineau, Burleigh, Cass, Cavalier and 26 more | 5 hr |
| Aug 22, 5:59 PM CDT | Mesoscale Discussion | SPC | Barnes, Benson, Cass, Dickey, Eddy, Foster and 17 more | 91 min |
| Aug 22, 3:38 PM CDT | Mesoscale Discussion | SPC | Gregory, Tripp | 97 min |
| Aug 22, 6:31 PM CDT | Tornado Watch | SPC | Aurora, Davison, Douglas, Hanson, Hutchinson, Jerauld and 4 more | 3 hr |
Nearby
Mesoscale 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.