Alert archive / South Dakota / Mesoscale Discussions in 2017

Mesoscale Discussion 1374

July 20, 20179 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2017, 11:25 PM CDT for 9 counties in South Dakota. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Jul 20, 2017, 11:25 PM CDT (04:25 UTC)
Expired: Jul 21, 2017, 12:30 AM CDT
In force: 65 min
Issued by: the Storm Prediction Center

Counties Brown County, SD, Campbell County, SD, Edmunds County, SD, Faulk County, SD, McPherson County, SD, Potter County, SD, Spink County, SD, Sully County, SD, Walworth County, SD

The radar

The Aberdeen radar (KABR), 87 km from the middle of the area, began a volume at 04:25 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, 4.4 hours before the alert went out and 99 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: 25 J/kg
Mixed-layer CIN: -379 J/kg
Mixed-layer LCL: 2211 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: -37 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 20, 7:31 PM CDT	Mesoscale Discussion	SPC	Campbell, Corson, Dewey, Meade, Perkins, Ziebach	89 min
Jul 20, 10:26 PM CDT	Severe Thunderstorm Watch	SPC	Brown, Campbell, Edmunds, Faulk, Hand, Hyde and 5 more	3 hr
Jul 21, 2:20 PM CDT	Mesoscale Discussion	SPC	Brown, Campbell, Day, Edmunds, Faulk, McPherson and 6 more	2 hr
Jul 21, 3:07 PM CDT	Severe Thunderstorm Watch	SPC	Brown, Campbell, Corson, Day, Dewey, Edmunds and 11 more	10 hr
Jul 21, 3:53 PM CDT	Mesoscale Discussion	SPC	Brown, Campbell, Corson, Day, Dewey, Edmunds and 8 more	97 min
Jul 21, 6:25 PM CDT	Mesoscale Discussion	SPC	Grant, Marshall, Roberts	95 min

Nearby

Mesoscale Discussions in South 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.