Alert archive / North Dakota / Mesoscale Discussions in 2018

Mesoscale Discussion 913

June 28, 201818 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 28, 2018, 3:52 AM CDT for 18 counties in North Dakota. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Jun 28, 2018, 3:52 AM CDT (08:52 UTC)
Expired: Jun 28, 2018, 5:15 AM CDT
In force: 83 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Barnes County, ND, Burleigh County, ND, Cass County, ND, Dickey County, ND, Emmons County, ND, Foster County, ND, Grant County, ND, Griggs County, ND, Kidder County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Morton County, ND, Oliver County, ND, Ransom County, ND, Sargent County, ND, Sioux County, ND, Stutsman County, ND

The radar

The Bismarck radar (KBIS), 37 km from the middle of the area, began a volume at 08:55 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

Bismarck Municip, ND (KBIS), launched 00:00Z, 8.9 hours before the alert went out and 32 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2452 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

631 
ACUS11 KWNS 280852
SWOMCD
SPC MCD 280852 
NDZ000-281015-

Mesoscale Discussion 0913
NWS Storm Prediction Center Norman OK
0352 AM CDT Thu Jun 28 2018

Areas affected...southern North Dakota

Concerning...Severe potential...Watch unlikely 

Valid 280852Z - 281015Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated large hail will be possible with the strongest
thunderstorms. A watch is not expected given the isolated nature of
the threat.

DISCUSSION...Isolated thunderstorms are developing within a warm-air
advection regime atop a remnant frontal boundary across southern
North Dakota. These thunderstorms should continue to move east with
time owing to deep westerly flow through the cloud bearing layer.
Deep-layer shear values are on the order of 50 knots and a parcel
source region characterized by most-unstable CAPE values in excess
of 1000 J/kg will support updraft organization and longevity --
including elevated transient supercell-like structures. Despite
mid-level lapse rates across on the order of 5-6 C/km, the degree of
instability suggests that isolated large hail will be possible with
the strongest thunderstorm cores. 

A watch is currently not anticipated given the relative isolated
nature of the threat.

..Marsh/Guyer.. 06/28/2018

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

ATTN...WFO...FGF...BIS...

LAT...LON   46740246 47630134 47419692 46059703 46100145 46740246

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 28, 7:40 AM CDT	Mesoscale Discussion	SPC	Adams, Barnes, Burleigh, Cass, Dickey, Emmons and 18 more	3 hr
Jun 28, 1:06 PM CDT	Mesoscale Discussion	SPC	Benson, Burleigh, Eddy, Foster, Grand Forks, Griggs and 8 more	114 min
Jun 28, 1:33 PM CDT	Severe Thunderstorm Watch	SPC	Cass, Grand Forks, Steele, Traill	6 hr
Jun 28, 3:16 PM CDT	Tornado Watch	SPC	Adams, Barnes, Benson, Billings, Bowman, Burleigh and 31 more	8 hr
Jun 28, 3:35 PM CDT	Mesoscale Discussion	SPC	Billings, Bowman, Golden Valley, McKenzie, Slope	2 hr
Jun 28, 3:53 PM CDT	Mesoscale Discussion	SPC	Cass, Grand Forks, Steele, Traill	97 min
Jun 28, 5:23 PM CDT	Mesoscale Discussion	SPC	Grand Forks, Traill	97 min
Jun 28, 6:59 PM CDT	Mesoscale Discussion	SPC	Adams, Benson, Billings, Bowman, Burleigh, Dunn and 22 more	91 min

Nearby

Mesoscale Discussions in North Dakota, 2018 Every mesoscale discussion in 2018

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.