Alert archive / South Dakota / Mesoscale Discussions in 2016

Mesoscale Discussion 1634

September 4, 201619 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Sep 4, 2016, 4:01 PM CDT for 19 counties in South Dakota. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Sep 4, 2016, 4:01 PM CDT (21:01 UTC)
Expired: Sep 4, 2016, 5:30 PM CDT
In force: 89 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

Counties Aurora County, SD, Beadle County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Edmunds County, SD, Faulk County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jerauld County, SD, Jones County, SD, Lyman County, SD, McPherson County, SD, Potter County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD

The radar

The Aberdeen radar (KABR), 135 km from the middle of the area, began a volume at 21:03 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 466Sep 4, 4:50 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 9.0 hours before the alert went out and 97 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: 37 J/kg
Mixed-layer CIN: -585 J/kg
Mixed-layer LCL: 701 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 202 m²/s²
0-3 km storm-relative helicity: 168 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 4, 2:46 PM CDT	Mesoscale Discussion	SPC	Bennett, Haakon, Jackson, Jones, Lyman, Mellette and 4 more	119 min
Sep 4, 3:24 PM CDT	Severe Thunderstorm Watch	SPC	Bennett, Custer, Fall River, Haakon, Jackson, Mellette and 4 more	7 hr
Sep 4, 4:53 PM CDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Brown, Brule, Buffalo, Campbell and 23 more	7 hr
Sep 4, 6:07 PM CDT	Mesoscale Discussion	SPC	Bennett, Custer, Fall River, Jackson, Oglala Lakota	113 min
Sep 4, 6:56 PM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brown, Brule, Buffalo, Clark and 25 more	94 min

Nearby

Mesoscale Discussions in South Dakota, 2016 Every mesoscale discussion in 2016

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.