Alert archive / North Dakota / Mesoscale Discussions in 2011

Mesoscale Discussion 2087

August 31, 20115 counties in Montana; 16 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 31, 2011, 7:24 PM MDT for 5 counties in Montana; 16 counties in North Dakota. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: Aug 31, 2011, 7:24 PM MDT (01:24 UTC)
Expired: Aug 31, 2011, 8:30 PM MDT
In force: 66 min
Issued by: the Storm Prediction Center

All 21 counties

Dawson County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Wibaux County, MT, Billings County, ND, Bottineau County, ND, Burke County, ND, Divide County, ND, Dunn County, ND, Golden Valley County, ND, McHenry County, ND, McKenzie County, ND, McLean County, ND, Mercer County, ND, Mountrail County, ND, Oliver County, ND, Renville County, ND, Sheridan County, ND, Ward County, ND, Williams County, ND

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 819Aug 31, 7:55 PM MDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 00:00Z, 1.4 hours before the alert went out and 229 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: 1855 J/kg
Mixed-layer CIN: -213 J/kg
Mixed-layer LCL: 1413 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 306 m²/s²
0-3 km storm-relative helicity: 486 m²/s²
Significant tornado parameter: 0.0
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
Aug 31, 7:53 PM MDT	Severe Thunderstorm Watch	SPC	Richland, Roosevelt, Sheridan, Wibaux	7 hr
Aug 31, 9:54 PM MDT	Mesoscale Discussion	SPC	Bottineau, Burke, Burleigh, Hettinger, McHenry, McLean and 9 more	96 min
Aug 31, 11:02 PM MDT	Mesoscale Discussion	SPC	Benson, Bottineau, Burleigh, Eddy, Foster, Griggs and 14 more	58 min
Aug 31, 11:48 PM MDT	Severe Thunderstorm Watch	SPC	Benson, Cavalier, Eddy, Grand Forks, Griggs, Nelson and 6 more	6 hr
Sep 1, 2:40 AM MDT	Mesoscale Discussion	SPC	Benson, Cavalier, Eddy, Foster, Grand Forks, Griggs and 6 more	65 min

Nearby

Mesoscale Discussions in North Dakota, 2011 Mesoscale Discussions in Montana, 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.