Alert archive / Montana / Mesoscale Discussions in 2017

Mesoscale Discussion 1343

July 19, 201711 counties in Montana; 9 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 19, 2017, 1:36 AM MDT for 11 counties in Montana; 9 counties in North Dakota. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Jul 19, 2017, 1:36 AM MDT (07:36 UTC)
Expired: Jul 19, 2017, 3:30 AM MDT
In force: 114 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Petroleum County, MT, Phillips County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Valley County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Hettinger County, ND, McKenzie County, ND, Slope County, ND, Stark County, ND

The radar

The Glasgow radar (KGGW), 153 km from the middle of the area, began a volume at 07:36 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, 7.6 hours before the alert went out and 380 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: 319 J/kg
Mixed-layer CIN: -81 J/kg
Mixed-layer LCL: 1690 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: -30 m²/s²
0-3 km storm-relative helicity: 74 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.2

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
Jul 19, 6:01 AM MDT	Mesoscale Discussion	SPC	Dawson, Richland, Wibaux	119 min
Jul 19, 8:59 AM MDT	Mesoscale Discussion	SPC	Cavalier, Pembina, Ramsey, Rolette, Towner, Walsh	3 hr

Nearby

Mesoscale Discussions in Montana, 2017 Mesoscale Discussions in North Dakota, 2017 Every mesoscale discussion in 2017

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.