Alert archive / North Dakota / Mesoscale Discussions in 2021
Mesoscale Discussion 1654
The Storm Prediction Center issued this mesoscale discussion at Aug 30, 2021, 4:58 PM MDT for 10 counties in North Dakota. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- Aug 30, 2021, 4:58 PM MDT (22:58 UTC)
- Expired
- Aug 30, 2021, 6:00 PM MDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 476
Counties Adams County, ND, Dunn County, ND, Emmons County, ND, Grant County, ND, Hettinger County, ND, Mercer County, ND, Morton County, ND, Oliver County, ND, Sioux County, ND, Stark County, ND
The radar
The Bismarck radar (KBIS), 94 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 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, 11.0 hours before the alert went out and 99 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
- 8 J/kg
- Mixed-layer CIN
- -262 J/kg
- Mixed-layer LCL
- 1949 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 93 m²/s²
- 0-3 km storm-relative helicity
- 131 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
212
ACUS11 KWNS 302258
SWOMCD
SPC MCD 302258
NDZ000-310000-
Mesoscale Discussion 1654
NWS Storm Prediction Center Norman OK
0558 PM CDT Mon Aug 30 2021
Areas affected...Southwestern and south-central North Dakota
Concerning...Severe Thunderstorm Watch 476...
Valid 302258Z - 310000Z
The severe weather threat for Severe Thunderstorm Watch 476
continues.
SUMMARY...Scattered supercells have produced large to very large
hail. The environment will support the continuation of mature storms
for at least some period beyond 7 PM CDT. Either a local extension
in time or new watch will likely be needed.
DISCUSSION...Scattered supercell thunderstorms continue to move
slowly south and east to the west of Bismarck. Deep-layer shear and
a modest increase in southerly 850 mb winds should maintain the more
mature supercells even beyond the 7 PM CDT scheduled watch
expiration. With the continued potential for large to very large
hail and isolated damaging winds, either a local extension in time
of WW 476 or a new watch will likely be needed before 7 PM CDT.
..Wendt.. 08/30/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BIS...
LAT...LON 47570322 47840318 47760177 47330112 46300016 46030017
45960264 47570322SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 30, 12:38 PM MDT | Severe Thunderstorm Watch | SPC | Adams, Burleigh, Dunn, Emmons, Grant, Hettinger and 6 more | 5 hr |
| Aug 30, 1:54 PM MDT | Mesoscale Discussion | SPC | Adams, Dunn, Emmons, Grant, Hettinger, McLean and 5 more | 2 hr |
| Aug 30, 5:56 PM MDT | Severe Thunderstorm Watch | SPC | Adams, Burleigh, Dunn, Emmons, Grant, Hettinger and 6 more | 3 hr |
Nearby
Mesoscale 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.