Alert archive / Montana / Mesoscale Discussions in 2011

Mesoscale Discussion 1116

June 6, 201115 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jun 6, 2011, 4:45 PM MDT for 15 counties in Montana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 6, 2011, 4:45 PM MDT (22:45 UTC)
Expired: Jun 6, 2011, 6:45 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Big Horn County, MT, Carbon County, MT, Fergus County, MT, Golden Valley County, MT, Judith Basin County, MT, Meagher County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Rosebud County, MT, Stillwater County, MT, Sweet Grass County, MT, Treasure County, MT, Wheatland County, MT, Yellowstone County, MT

The radar

The Billings radar (KBLX), 31 km from the middle of the area, began a volume at 22:49 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 435Jun 6, 5:45 PM MDT

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.8 hours before the alert went out and 205 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: 1546 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 218 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 6, 2:13 PM MDT	Mesoscale Discussion	SPC	Beaverhead, Broadwater, Deer Lodge, Gallatin, Jefferson, Madison and 5 more	2 hr
Jun 6, 4:13 PM MDT	Severe Thunderstorm Watch	SPC	Beaverhead, Broadwater, Cascade, Chouteau, Deer Lodge, Fergus and 19 more	6 hr
Jun 6, 5:46 PM MDT	Tornado Watch	SPC	Big Horn, Carbon, Fergus, Garfield, Golden Valley, Judith Basin and 9 more	7 hr

Nearby

Mesoscale Discussions in Montana, 2011 Every mesoscale discussion in 2011

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.