Alert archive / South Dakota / Mesoscale Discussions in 2017

Mesoscale Discussion 1231

July 4, 20174 counties in North Dakota; 17 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2017, 5:11 PM CDT for 4 counties in North Dakota; 17 counties in South Dakota. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Jul 4, 2017, 5:11 PM CDT (22:11 UTC)
Expired: Jul 4, 2017, 7:45 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 21 counties

Emmons County, ND, Logan County, ND, McIntosh County, ND, Sioux County, ND, Campbell County, SD, Corson County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jones County, SD, Lyman County, SD, McPherson County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The radar

The Aberdeen radar (KABR), 152 km from the middle of the area, began a volume at 22:13 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 nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 10.2 hours before the alert went out and 155 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: 1122 J/kg
Mixed-layer CIN: -283 J/kg
Mixed-layer LCL: 1795 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 79 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
Jul 4, 3:33 PM CDT	Mesoscale Discussion	SPC	Barnes, Cass, Grand Forks, Griggs, Nelson, Pembina and 4 more	2 hr
Jul 4, 6:03 PM CDT	Severe Thunderstorm Watch	SPC	Barnes, Cass, Grand Forks, Griggs, Nelson, Pembina and 6 more	8 hr

Nearby

Mesoscale Discussions in South Dakota, 2017 Mesoscale Discussions in North Dakota, 2017 Every mesoscale discussion in 2017

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.