Alert archive / South Dakota / Mesoscale Discussions in 2006

Mesoscale Discussion 1874

August 24, 2006Lyon County, Iowa; 8 counties in Minnesota; 17 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 24, 2006, 5:36 PM CDT for Lyon County, Iowa; 8 counties in Minnesota; 17 counties in South Dakota. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Aug 24, 2006, 5:36 PM CDT (22:36 UTC)
Expired: Aug 24, 2006, 6:30 PM CDT
In force: 54 min
Issued by: the Storm Prediction Center

All 26 counties

Lyon County, IA, Cottonwood County, MN, Jackson County, MN, Lincoln County, MN, Lyon County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Aurora County, SD, Beadle County, SD, Brookings County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD, Turner County, SD

The radar

The Sioux Falls radar (KFSD), 36 km from the middle of the area, began a volume at 22:37 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 746Aug 24, 5:50 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 10.6 hours before the alert went out and 205 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: 3787 J/kg
Mixed-layer CIN: -166 J/kg
Mixed-layer LCL: 769 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

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 24, 1:05 PM CDT	Mesoscale Discussion	SPC	Allamakee	115 min
Aug 24, 3:17 PM CDT	Tornado Watch	SPC	Allamakee, Howard, Mitchell, Winneshiek	9 hr
Aug 24, 5:51 PM CDT	Tornado Watch	SPC	Clay, Dickinson, Lyon, O'Brien, Osceola, Sioux	4 hr
Aug 24, 6:03 PM CDT	Mesoscale Discussion	SPC	Allamakee, Howard, Mitchell, Winneshiek	87 min
Aug 24, 8:44 AM CDT	Severe Thunderstorm Watch	SPC	Anoka, Benton, Blue Earth, Brown, Carver, Chippewa and 39 more	7 hr
Aug 24, 10:18 AM CDT	Mesoscale Discussion	SPC	Anoka, Benton, Blue Earth, Brown, Carver, Chippewa and 38 more	87 min
Aug 24, 11:52 AM CDT	Severe Thunderstorm Watch	SPC	Big Stone, Clay, Grant, Otter Tail, Traverse, Wilkin	5 hr
Aug 24, 2:44 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Brown, Cottonwood, Dodge, Goodhue, Lac qui Parle and 16 more	3 hr
Aug 24, 2:57 PM CDT	Mesoscale Discussion	SPC	Big Stone, Traverse, Wilkin	2 hr
Aug 24, 3:40 PM CDT	Tornado Watch	SPC	Big Stone, Clay, Grant, Otter Tail, Traverse, Wilkin	6 hr

Nearby

Mesoscale Discussions in South Dakota, 2006 Mesoscale Discussions in Minnesota, 2006 Mesoscale Discussions in Iowa, 2006 Every mesoscale discussion in 2006

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.