Alert archive / North Dakota / Mesoscale Discussions in 2021

Mesoscale Discussion 1651

August 30, 202111 counties in North Dakota; Campbell County, Corson County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 30, 2021, 1:54 PM MDT for 11 counties in North Dakota; Campbell County, Corson County, South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 30, 2021, 1:54 PM MDT (19:54 UTC)
Expired: Aug 30, 2021, 4:00 PM MDT
In force: 2 hr
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, McLean County, ND, Mercer County, ND, Morton County, ND, Oliver County, ND, Sioux County, ND, Stark County, ND, Campbell County, SD, Corson County, SD

The radar

The Bismarck radar (KBIS), 62 km from the middle of the area, began a volume at 19:59 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, 7.9 hours before the alert went out and 65 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

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

Open this sounding in Storm Lab

The text

As transmitted.

172 
ACUS11 KWNS 301954
SWOMCD
SPC MCD 301954 
NDZ000-SDZ000-302200-

Mesoscale Discussion 1651
NWS Storm Prediction Center Norman OK
0254 PM CDT Mon Aug 30 2021

Areas affected...central into southern North Dakota

Concerning...Severe Thunderstorm Watch 476...

Valid 301954Z - 302200Z

The severe weather threat for Severe Thunderstorm Watch 476
continues.

SUMMARY...The threat for large hail continues across central North
Dakota, and a few additional cells may develop through late
afternoon. Watch expansion may be considered.

DISCUSSION...A cluster of cells, some severe, continue to move very
slowly southeastward, near the Bismarck area. The southward motion
of the most intense cell suggests the storm is now ingesting surface
air. Given the favorable time of day, cells should maintain strength
and may increase in intensity.

West of the watch, visible satellite shows a cumulus field into
southwest ND, coincident with a surface heating axis. Here,
instability is maximized, and several models suggest isolated cells
developing. If this occurs, large hail will be likely, and
additional counties may need to be added into watch 476.

By evening, storms may shift into SD, necessitating watch
consideration there. Large hail should continue to be the main risk
across northern SD.

..Jewell.. 08/30/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ABR...BIS...UNR...

LAT...LON   45420011 45450164 45490223 45710281 46250312 46560319
            47070287 47620256 47920209 47870165 47460110 46770029
            46479989 46009971 45629976 45489977 45420011

SPC 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, 4:58 PM MDT	Mesoscale Discussion	SPC	Adams, Dunn, Emmons, Grant, Hettinger, Mercer and 4 more	62 min
Aug 30, 5:56 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Burleigh, Dunn, Emmons, Grant, Hettinger and 6 more	3 hr
Aug 30, 1:50 PM MDT	Mesoscale Discussion	SPC	Bennett, Custer, Fall River, Jackson, Lawrence, Meade and 2 more	115 min
Aug 30, 3:03 PM MDT	Severe Thunderstorm Watch	SPC	Bennett, Campbell, Corson, Custer, Dewey, Haakon and 13 more	6 hr

Nearby

Mesoscale Discussions in North Dakota, 2021 Mesoscale Discussions in South Dakota, 2021 Every 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.