Alert archive / Montana / Mesoscale Discussions in 2011

Mesoscale Discussion 1546

July 8, 20114 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2011, 5:34 PM MDT for 4 counties in Montana. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Jul 8, 2011, 5:34 PM MDT (23:34 UTC)
Expired: Jul 8, 2011, 6:30 PM MDT
In force: 56 min
Issued by: the Storm Prediction Center

Counties Custer County, MT, Powder River County, MT, Rosebud County, MT, Treasure County, MT

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 11.6 hours before the alert went out and 256 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: 232 J/kg
Mixed-layer CIN: -269 J/kg
Mixed-layer LCL: 1530 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 246 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

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
Jul 8, 1:13 PM MDT	Mesoscale Discussion	SPC	Dawson, Fallon, Richland, Roosevelt, Sheridan, Wibaux	62 min
Jul 8, 1:38 PM MDT	Mesoscale Discussion	SPC	Carbon, Gallatin, Golden Valley, Madison, Park, Stillwater and 3 more	97 min

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.