Alert archive / North Dakota / Mesoscale Discussions in 2011

Mesoscale Discussion 1686

July 22, 20118 counties in Montana; 14 counties in North Dakota; Corson County, Harding County, Perkins County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 22, 2011, 10:05 AM MDT for 8 counties in Montana; 14 counties in North Dakota; Corson County, Harding County, Perkins County, South Dakota. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Jul 22, 2011, 10:05 AM MDT (16:05 UTC)
Expired: Jul 22, 2011, 11:00 AM MDT
In force: 55 min
Issued by: the Storm Prediction Center

All 25 counties

Custer County, MT, Dawson County, MT, Fallon County, MT, McCone County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Grant County, ND, Hettinger County, ND, McKenzie County, ND, Mercer County, ND, Morton County, ND, Oliver County, ND, Slope County, ND, Stark County, ND, Williams County, ND, Corson County, SD, Harding County, SD, Perkins County, SD

The radar

The Bismarck radar (KBIS), 224 km from the middle of the area, began a volume at 16:04 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.

Tornado Watch 671Jul 22, 1:25 PM MDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 4.1 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: 1474 J/kg
Mixed-layer CIN: -117 J/kg
Mixed-layer LCL: 797 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: -39 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 13.8

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
Jul 22, 1:06 PM MDT	Mesoscale Discussion	SPC	Big Horn, Custer, Daniels, Dawson, Fallon, Garfield and 11 more	24 min
Jul 22, 1:25 PM MDT	Tornado Watch	SPC	Carter, Custer, Daniels, Dawson, Fallon, Garfield and 11 more	8 hr
Jul 22, 4:17 PM MDT	Mesoscale Discussion	SPC	Big Horn, Carbon, Carter, Custer, Dawson, Fallon and 13 more	88 min
Jul 22, 4:35 PM MDT	Tornado Watch	SPC	Adams, Billings, Bowman, Burke, Burleigh, Divide and 21 more	8 hr
Jul 22, 4:46 PM MDT	Mesoscale Discussion	SPC	Barnes, Dickey, LaMoure, Logan, McIntosh, Ransom and 2 more	89 min
Jul 22, 5:14 PM MDT	Tornado Watch	SPC	Dickey, LaMoure, Ransom, Richland, Sargent	8 hr
Jul 21, 6:10 PM MDT	Mesoscale Discussion	SPC	Bennett, Jackson, Jones, Lyman, Mellette, Todd and 1 more	95 min
Jul 22, 2:00 PM MDT	Mesoscale Discussion	SPC	Beadle, Brookings, Clark, Codington, Day, Deuel and 12 more	90 min
Jul 22, 5:22 PM MDT	Mesoscale Discussion	SPC	Brule, Buffalo, Gregory, Lyman, Mellette, Todd and 1 more	53 min

Nearby

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