Alert archive / Montana / Mesoscale Discussions in 2012

Mesoscale Discussion 1255

June 23, 20124 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jun 23, 2012, 7:36 PM MDT for 4 counties in Montana. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Jun 23, 2012, 7:36 PM MDT (01:36 UTC)
Expired: Jun 23, 2012, 9:00 PM MDT
In force: 84 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Flathead County, MT, Lake County, MT, Pondera County, MT, Teton County, MT

The radar

The Great Falls radar (KTFX), 129 km from the middle of the area, began a volume at 01:38 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 nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 1.6 hours before the alert went out and 183 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: 1027 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 1751 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 150 m²/s²
0-3 km storm-relative helicity: 208 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 7.4

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 24, 3:47 AM MDT	Mesoscale Discussion	SPC	Daniels, Roosevelt, Sheridan, Valley	88 min
Jun 24, 8:16 AM MDT	Mesoscale Discussion	SPC	Richland, Roosevelt, Sheridan	89 min
Jun 24, 8:31 AM MDT	Severe Thunderstorm Watch	SPC	Daniels, Richland, Roosevelt, Sheridan	5 hr
Jun 24, 11:24 AM MDT	Mesoscale Discussion	SPC	Daniels, Richland, Roosevelt, Sheridan	2 hr

Nearby

Mesoscale Discussions in Montana, 2012 Every mesoscale discussion in 2012

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.