Alert archive / North Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 1578
The Storm Prediction Center issued this mesoscale discussion at Aug 22, 2021, 5:59 PM CDT for 23 counties in North Dakota; 17 counties in South Dakota. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Aug 22, 2021, 5:59 PM CDT (22:59 UTC)
- Expired
- Aug 22, 2021, 7:30 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 455
All 40 counties
Barnes County, ND, Benson County, ND, Cass County, ND, Dickey County, ND, Eddy County, ND, Foster County, ND, Grand Forks County, ND, Griggs County, ND, Kidder County, ND, LaMoure County, ND, Logan County, ND, McHenry County, ND, McIntosh County, ND, Nelson County, ND, Pierce County, ND, Ramsey County, ND, Ransom County, ND, Sargent County, ND, Sheridan County, ND, Steele County, ND, Stutsman County, ND, Walsh County, ND, Wells County, ND, Beadle County, SD, Brookings County, SD, Brown County, SD, Campbell County, SD, Clark County, SD, Codington County, SD, Day County, SD, Edmunds County, SD, Faulk County, SD, Hamlin County, SD, Hand County, SD, Hyde County, SD, Kingsbury County, SD, Marshall County, SD, McPherson County, SD, Roberts County, SD, Spink County, SD
The radar
The Aberdeen radar (KABR), 76 km from the middle of the area, began a volume at 22:59 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 12:00Z, 11.0 hours before the alert went out and 134 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
- 1388 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 135 m²/s²
- 0-3 km storm-relative helicity
- 261 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
528 ACUS11 KWNS 222259 SWOMCD SPC MCD 222259 SDZ000-NDZ000-230030- Mesoscale Discussion 1578 NWS Storm Prediction Center Norman OK 0559 PM CDT Sun Aug 22 2021 Areas affected...Eastern Dakotas Concerning...Severe Thunderstorm Watch 455... Valid 222259Z - 230030Z The severe weather threat for Severe Thunderstorm Watch 455 continues. SUMMARY...Severe threat will gradually shift east across ww455. DISCUSSION...Well-defined short-wave trough is ejecting across the Dakotas this evening. Scattered severe thunderstorms have developed ahead of this feature, within a narrow instability axis. This activity is propagating east at roughly 35kt and should advance east of the higher buoyancy within the next few hours as the short-wave progresses downstream. However, latest satellite imagery suggests deepening updrafts west of Jamestown and this activity may mature into strong/severe thunderstorms before encountering less-buoyant air mass over eastern ND. Activity may remain more discrete over SD along southern fringe of short-wave influence, but storms should move a bit slower and linger across this portion of the watch. ..Darrow.. 08/22/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...FSD...ABR...BIS... LAT...LON 44349963 48630089 48639760 44349661 44349963
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 22, 2:21 PM CDT | Mesoscale Discussion | SPC | Benson, Burleigh, Dickey, Eddy, Emmons, Foster and 9 more | 2 hr |
| Aug 22, 3:36 PM CDT | Severe Thunderstorm Watch | SPC | Barnes, Benson, Bottineau, Burleigh, Cass, Cavalier and 26 more | 5 hr |
| 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.