Alert archive / South Dakota / Mesoscale Discussions in 2018

Mesoscale Discussion 1022

July 9, 2018Oglala Lakota County, Pennington County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2018, 4:41 AM MDT for Oglala Lakota County, Pennington County, South Dakota. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: Jul 9, 2018, 4:41 AM MDT (10:41 UTC)
Expired: Jul 9, 2018, 5:45 AM MDT
In force: 64 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Oglala Lakota County, SD, Pennington County, SD

The radar

The Rapid City radar (KUDX), 57 km from the middle of the area, began a volume at 10:43 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

Aberdeen, SD (KABR), launched 00:00Z, 10.7 hours before the alert went out and 387 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: 2501 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 1738 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 170 m²/s²
0-3 km storm-relative helicity: 237 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 23.3

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 8, 6:58 PM MDT	Mesoscale Discussion	SPC	Brown, Clark, Codington, Day, Deuel, Grant and 3 more	2 hr

Nearby

Mesoscale Discussions in South Dakota, 2018 Every mesoscale discussion in 2018

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.