Alert archive / Montana / Mesoscale Discussions in 2018

Mesoscale Discussion 923

June 28, 201813 counties in Montana; 5 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jun 28, 2018, 2:35 PM MDT for 13 counties in Montana; 5 counties in North Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 28, 2018, 2:35 PM MDT (20:35 UTC)
Expired: Jun 28, 2018, 5:00 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 95%

Counties Big Horn County, MT, Carter County, MT, Custer County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Rosebud County, MT, Treasure County, MT, Wibaux County, MT, Billings County, ND, Bowman County, ND, Golden Valley County, ND, McKenzie County, ND, Slope County, ND

The radar

The Glasgow radar (KGGW), 207 km from the middle of the area, began a volume at 20:38 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.

Tornado Watch 235Jun 28, 3:40 PM MDT

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 8.6 hours before the alert went out and 208 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: 2598 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 66 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 28, 3:42 PM MDT	Tornado Watch	SPC	Carter, Custer, Dawson, Fallon, Garfield, McCone and 6 more	7 hr
Jun 28, 5:59 PM MDT	Mesoscale Discussion	SPC	Big Horn, Carter, Custer, Dawson, Fallon, Garfield and 7 more	91 min
Jun 28, 2:52 AM MDT	Mesoscale Discussion	SPC	Barnes, Burleigh, Cass, Dickey, Emmons, Foster and 12 more	83 min
Jun 28, 6:40 AM MDT	Mesoscale Discussion	SPC	Adams, Barnes, Burleigh, Cass, Dickey, Emmons and 18 more	3 hr
Jun 28, 12:06 PM MDT	Mesoscale Discussion	SPC	Benson, Burleigh, Eddy, Foster, Grand Forks, Griggs and 8 more	114 min
Jun 28, 12:33 PM MDT	Severe Thunderstorm Watch	SPC	Cass, Grand Forks, Steele, Traill	6 hr
Jun 28, 2:16 PM MDT	Tornado Watch	SPC	Adams, Barnes, Benson, Billings, Bowman, Burleigh and 31 more	8 hr
Jun 28, 2:53 PM MDT	Mesoscale Discussion	SPC	Cass, Grand Forks, Steele, Traill	97 min
Jun 28, 4:23 PM MDT	Mesoscale Discussion	SPC	Grand Forks, Traill	97 min

Nearby

Mesoscale Discussions in Montana, 2018 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.