Alert archive / South Dakota / Mesoscale Discussions in 2004

Mesoscale Discussion 1633

July 12, 2004Boyd County, Keya Paha County, Nebraska; 18 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 12, 2004, 2:04 PM CDT for Boyd County, Keya Paha County, Nebraska; 18 counties in South Dakota. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued: Jul 12, 2004, 2:04 PM CDT (19:04 UTC)
Expired: Jul 12, 2004, 4:00 PM CDT
In force: 116 min
Issued by: the Storm Prediction Center

Counties Boyd County, NE, Keya Paha County, NE, Aurora County, SD, Bon Homme County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Lake County, SD, Lyman County, SD, McCook County, SD, Miner County, SD, Moody County, SD, Sanborn County, SD, Tripp County, SD

The radar

The Sioux Falls radar (KFSD), 177 km from the middle of the area, began a volume at 19:05 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 612Jul 12, 3:25 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 7.1 hours before the alert went out and 178 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: 12 J/kg
Mixed-layer CIN: -517 J/kg
Mixed-layer LCL: 2141 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: -106 m²/s²
0-3 km storm-relative helicity: 109 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
Jul 12, 3:25 PM CDT	Tornado Watch	SPC	Boyd, Cedar, Dixon, Holt, Knox	6 hr
Jul 12, 5:41 PM CDT	Mesoscale Discussion	SPC	Antelope, Boone, Boyd, Cedar, Colfax, Cuming and 16 more	2 hr
Jul 12, 6:20 PM CDT	Tornado Watch	SPC	Antelope, Boone, Burt, Cedar, Colfax, Cuming and 14 more	7 hr
Jul 11, 7:20 PM CDT	Severe Thunderstorm Watch	SPC	Butte, Corson, Dewey, Harding, Meade, Perkins and 2 more	8 hr
Jul 11, 9:54 PM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brule, Buffalo, Charles Mix, Davison and 12 more	3 hr
Jul 11, 11:34 PM CDT	Mesoscale Discussion	SPC	Brown, Campbell, Corson, Day, Edmunds, McPherson and 3 more	116 min
Jul 11, 11:50 PM CDT	Severe Thunderstorm Watch	SPC	Campbell, McPherson	6 hr
Jul 12, 1:29 AM CDT	Mesoscale Discussion	SPC	Brown, Campbell, McPherson, Marshall	91 min
Jul 12, 3:13 AM CDT	Mesoscale Discussion	SPC	Brown, Campbell, McPherson	92 min
Jul 12, 8:53 AM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brookings, Brown, Brule, Buffalo and 30 more	2 hr
Jul 12, 10:55 AM CDT	Severe Thunderstorm Watch	SPC	Beadle, Brookings, Clark, Codington, Day, Deuel and 4 more	5 hr

Nearby

Mesoscale Discussions in South Dakota, 2004 Mesoscale Discussions in Nebraska, 2004 Every mesoscale discussion in 2004

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.