Alert archive / South Dakota / Mesoscale Discussions in 2018

Mesoscale Discussion 1003

July 3, 201820 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 3, 2018, 10:38 PM CDT for 20 counties in South Dakota. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jul 3, 2018, 10:38 PM CDT (03:38 UTC)
Expired: Jul 4, 2018, 12:15 AM CDT
In force: 97 min
Issued by: the Storm Prediction Center

Counties Brown County, SD, Campbell County, SD, Clark County, SD, Corson County, SD, Day 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, McPherson County, SD, Potter County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The radar

The Aberdeen radar (KABR), 157 km from the middle of the area, began a volume at 03:40 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 262Jul 3, 11:00 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 3.6 hours before the alert went out and 143 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: 3627 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 889 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 14 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 4.1

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 3, 9:38 PM CDT	Mesoscale Discussion	SPC	Bennett, Butte, Custer, Fall River, Haakon, Harding and 7 more	2 hr
Jul 3, 11:02 PM CDT	Severe Thunderstorm Watch	SPC	Brown, Campbell, Clark, Corson, Day, Dewey and 13 more	6 hr
Jul 4, 3:14 AM CDT	Mesoscale Discussion	SPC	Beadle, Brown, Clark, Codington, Day, Edmunds and 14 more	91 min
Jul 4, 2:01 PM CDT	Mesoscale Discussion	SPC	Bon Homme, Charles Mix, Clay, Gregory, Union, Yankton	119 min
Jul 4, 5:35 PM CDT	Mesoscale Discussion	SPC	Bon Homme, Clay, Union, Yankton	115 min

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.