Alert archive / Montana / Mesoscale Discussions in 2018

Mesoscale Discussion 663

June 7, 20184 counties in Idaho; 12 counties in Montana; Park County, Teton County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 7, 2018, 1:20 PM MDT for 4 counties in Idaho; 12 counties in Montana; Park County, Teton County, Wyoming. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: Jun 7, 2018, 1:20 PM MDT (19:20 UTC)
Expired: Jun 7, 2018, 2:45 PM MDT
In force: 85 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Custer County, ID, Fremont County, ID, Lemhi County, ID, Valley County, ID, Beaverhead County, MT, Broadwater County, MT, Carbon County, MT, Deer Lodge County, MT, Gallatin County, MT, Jefferson County, MT, Madison County, MT, Park County, MT, Ravalli County, MT, Silver Bow County, MT, Stillwater County, MT, Sweet Grass County, MT, Park County, WY, Teton County, WY

The radar

The Pocatello radar (KSFX), 211 km from the middle of the area, began a volume at 19:21 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 12:00Z, 7.3 hours before the alert went out and 304 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: 16 J/kg
Mixed-layer CIN: -216 J/kg
Mixed-layer LCL: 1783 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: -35 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 7, 10:24 AM MDT	Mesoscale Discussion	SPC	Dawson, Fergus, Garfield, McCone, Musselshell, Petroleum and 5 more	66 min
Jun 7, 1:51 PM MDT	Mesoscale Discussion	SPC	Carter, Custer, Dawson, Fallon, McCone, Powder River and 5 more	84 min
Jun 7, 3:49 PM MDT	Severe Thunderstorm Watch	SPC	Big Horn, Carter, Custer, Fallon, Powder River, Rosebud and 1 more	9 hr
Jun 7, 5:16 PM MDT	Mesoscale Discussion	SPC	Carter, Custer, Dawson, Fallon, McCone, Powder River and 4 more	119 min

Nearby

Mesoscale Discussions in Montana, 2018 Mesoscale Discussions in Idaho, 2018 Mesoscale Discussions in Wyoming, 2018 Every mesoscale discussion in 2018

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.