Alert archive / Montana / Mesoscale Discussions in 2011

Mesoscale Discussion 1986

August 15, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2011, 1:38 PM MDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 15, 2011, 1:38 PM MDT (19:38 UTC)
Expired: Aug 15, 2011, 3:45 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 39 counties

Bannock County, ID, Bear Lake County, ID, Bonneville County, ID, Caribou County, ID, Clark County, ID, Custer County, ID, Franklin County, ID, Fremont County, ID, Lemhi County, ID, Madison County, ID, Oneida County, ID, Teton County, ID, Beaverhead County, MT, Broadwater County, MT, Carbon County, MT, Deer Lodge County, MT, Gallatin County, MT, Jefferson County, MT, Madison County, MT, Meagher County, MT, Park County, MT, Silver Bow County, MT, Stillwater County, MT, Sweet Grass County, MT, Wheatland County, MT, Box Elder County, UT, Cache County, UT, Davis County, UT, Morgan County, UT, Rich County, UT, Salt Lake County, UT, Summit County, UT, Tooele County, UT, Weber County, UT, Lincoln County, WY, Park County, WY, Sublette County, WY, Teton County, WY, Uinta County, WY

The radar

The Pocatello radar (KSFX), 76 km from the middle of the area, began a volume at 19:41 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

Riverton, WY (KRIW), launched 12:00Z, 7.6 hours before the alert went out and 296 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: 3743 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -25 m²/s²
0-3 km storm-relative helicity: -28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Aug 15, 2:47 PM MDT	Mesoscale Discussion	SPC	Fallon	58 min
Aug 15, 4:23 PM MDT	Severe Thunderstorm Watch	SPC	Carter, Custer, Dawson, Fallon, McCone, Powder River and 3 more	9 hr

Nearby

Mesoscale Discussions in Montana, 2011 Mesoscale Discussions in Idaho, 2011 Mesoscale Discussions in Utah, 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; radar from the NEXRAD Level II archive.