Alert archive / Montana / Mesoscale Discussions in 2016

Mesoscale Discussion 980

June 18, 201620 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2016, 2:43 PM MDT for 20 counties in Montana. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Jun 18, 2016, 2:43 PM MDT (20:43 UTC)
Expired: Jun 18, 2016, 4:15 PM MDT
In force: 92 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

Counties Blaine County, MT, Cascade County, MT, Chouteau County, MT, Daniels County, MT, Fergus County, MT, Garfield County, MT, Glacier County, MT, Hill County, MT, Judith Basin County, MT, Lewis and Clark County, MT, Liberty County, MT, McCone County, MT, Phillips County, MT, Pondera County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Teton County, MT, Toole County, MT, Valley County, MT

The radar

The Great Falls radar (KTFX), 37 km from the middle of the area, began a volume at 20:42 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 271Jun 18, 3:15 PM MDT

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 8.7 hours before the alert went out and 24 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: 1982 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 187 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 18, 3:16 PM MDT	Severe Thunderstorm Watch	SPC	Blaine, Cascade, Chouteau, Daniels, Dawson, Fergus and 14 more	8 hr
Jun 18, 5:56 PM MDT	Mesoscale Discussion	SPC	Blaine, Cascade, Chouteau, Daniels, Fergus, Garfield and 11 more	2 hr

Nearby

Mesoscale Discussions in Montana, 2016 Every mesoscale discussion in 2016

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.