Alert archive / Montana / Mesoscale Discussions in 2017

Mesoscale Discussion 1003

June 12, 201710 counties in Montana; 7 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 12, 2017, 6:00 PM MDT for 10 counties in Montana; 7 counties in Wyoming. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: Jun 12, 2017, 6:00 PM MDT (00:00 UTC)
Expired: Jun 12, 2017, 7:30 PM MDT
In force: 90 min
Issued by: the Storm Prediction Center

Counties Big Horn County, MT, Carbon County, MT, Golden Valley County, MT, Musselshell County, MT, Park County, MT, Stillwater County, MT, Sweet Grass County, MT, Treasure County, MT, Wheatland County, MT, Yellowstone County, MT, Big Horn County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Park County, WY, Sheridan County, WY, Washakie County, WY

The radar

The Billings radar (KBLX), 145 km from the middle of the area, began a volume at 00:02 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

Riverton, WY (KRIW), launched 00:00Z, 0.0 hours before the alert went out and 165 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: 804 J/kg
Mixed-layer CIN: -131 J/kg
Mixed-layer LCL: 2386 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: -26 m²/s²
0-3 km storm-relative helicity: 76 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

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 13, 4:58 PM MDT	Mesoscale Discussion	SPC	Blaine, Chouteau, Daniels, Dawson, Hill, Liberty and 6 more	2 hr
Jun 12, 8:02 PM MDT	Mesoscale Discussion	SPC	Campbell, Converse, Crook, Niobrara, Weston	58 min

Nearby

Mesoscale Discussions in Montana, 2017 Mesoscale Discussions in Wyoming, 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.