Alert archive / Montana / Mesoscale Discussions in 2013

Mesoscale Discussion 1133

June 19, 201315 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2013, 4:57 PM MDT for 15 counties in Montana. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Jun 19, 2013, 4:57 PM MDT (22:57 UTC)
Expired: Jun 19, 2013, 6:30 PM MDT
In force: 93 min
Issued by: the Storm Prediction Center

Counties Broadwater County, MT, Cascade County, MT, Chouteau County, MT, Fergus County, MT, Golden Valley County, MT, Judith Basin County, MT, Lewis and Clark County, MT, Meagher County, MT, Musselshell County, MT, Pondera County, MT, Stillwater County, MT, Sweet Grass County, MT, Teton County, MT, Wheatland County, MT, Yellowstone County, MT

The radar

The Billings radar (KBLX), 132 km from the middle of the area, began a volume at 23:01 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.

Severe Thunderstorm Watch 330Jun 19, 8:20 PM MDT

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.0 hours before the alert went out and 106 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: 21 J/kg
Mixed-layer CIN: -449 J/kg
Mixed-layer LCL: 1124 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 102 m²/s²
0-3 km storm-relative helicity: 323 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.5

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 18, 8:21 PM MDT	Mesoscale Discussion	SPC	Broadwater, Cascade, Chouteau, Flathead, Glacier, Granite and 9 more	54 min
Jun 19, 1:21 PM MDT	Mesoscale Discussion	SPC	Broadwater, Cascade, Chouteau, Gallatin, Glacier, Hill and 12 more	114 min
Jun 19, 3:04 PM MDT	Severe Thunderstorm Watch	SPC	Blaine, Broadwater, Cascade, Chouteau, Fergus, Glacier and 9 more	7 hr

Nearby

Mesoscale Discussions in Montana, 2013 Every mesoscale discussion in 2013

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.