Alert archive / South Dakota / Mesoscale Discussions in 2011

Mesoscale Discussion 1507

July 4, 20115 counties in Nebraska; 38 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2011, 11:14 PM CDT for 5 counties in Nebraska; 38 counties in South Dakota. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Jul 4, 2011, 11:14 PM CDT (04:14 UTC)
Expired: Jul 5, 2011, 12:45 AM CDT
In force: 91 min
Issued by: the Storm Prediction Center

All 43 counties

Boyd County, NE, Brown County, NE, Holt County, NE, Keya Paha County, NE, Rock County, NE, Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Clark County, SD, Codington County, SD, Davison County, SD, Day County, SD, Douglas County, SD, Edmunds County, SD, Faulk County, SD, Gregory County, SD, Hamlin County, SD, Hand County, SD, Hanson County, SD, Hughes County, SD, Hutchinson County, SD, Hyde County, SD, Jerauld County, SD, Jones County, SD, Kingsbury County, SD, Lake County, SD, Lyman County, SD, Marshall County, SD, McCook County, SD, Mellette County, SD, Miner County, SD, Potter County, SD, Roberts County, SD, Sanborn County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Tripp County, SD

The radar

The Aberdeen radar (KABR), 213 km from the middle of the area, began a volume at 04:16 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 599Jul 4, 11:40 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 4.2 hours before the alert went out and 159 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: 3256 J/kg
Mixed-layer CIN: -52 J/kg
Mixed-layer LCL: 1088 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 94 m²/s²
0-3 km storm-relative helicity: 150 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 9.4

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
Jul 5, 2:17 PM CDT	Mesoscale Discussion	SPC	Dawes, Sheridan	73 min
Jul 5, 2:49 PM CDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Butler, Cass, Clay and 36 more	86 min
Jul 5, 3:32 PM CDT	Mesoscale Discussion	SPC	Dakota, Dixon	88 min
Jul 5, 4:47 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Arthur, Buffalo, Butler, Cass, Chase and 52 more	8 hr
Jul 5, 6:19 PM CDT	Mesoscale Discussion	SPC	Cheyenne	56 min
Jul 4, 7:59 PM CDT	Mesoscale Discussion	SPC	Beadle, Bennett, Brown, Brule, Buffalo, Campbell and 28 more	2 hr
Jul 4, 11:41 PM CDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Brookings, Brown, Brule, Buffalo and 32 more	5 hr

Nearby

Mesoscale Discussions in South Dakota, 2011 Mesoscale Discussions in Nebraska, 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.