Alert archive / South Dakota / Mesoscale Discussions in 2018

Mesoscale Discussion 442

May 17, 2018Dickey County, Emmons County, McIntosh County, North Dakota; 14 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 17, 2018, 3:47 PM CDT for Dickey County, Emmons County, McIntosh County, North Dakota; 14 counties in South Dakota. It was in force for 28 min.

The area

The outline as issued.

The facts

Issued: May 17, 2018, 3:47 PM CDT (20:47 UTC)
Expired: May 17, 2018, 4:15 PM CDT
In force: 28 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

Counties Dickey County, ND, Emmons County, ND, McIntosh County, ND, Beadle County, SD, Brown County, SD, Campbell County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, McPherson County, SD, Potter County, SD, Spink County, SD, Sully County, SD, Walworth County, SD

The radar

The Aberdeen radar (KABR), 100 km from the middle of the area, began a volume at 20:47 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 102May 17, 4:00 PM CDT

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 8.8 hours before the alert went out and 111 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: 100 J/kg
Mixed-layer CIN: -173 J/kg
Mixed-layer LCL: 2045 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -20 m²/s²
0-3 km storm-relative helicity: 8 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
May 17, 1:58 PM CDT	Mesoscale Discussion	SPC	Adams, Bowman, Hettinger, Slope	92 min
May 17, 4:03 PM CDT	Severe Thunderstorm Watch	SPC	Dickey, Emmons, McIntosh, Sioux	6 hr
May 17, 5:54 PM CDT	Mesoscale Discussion	SPC	Adams, Bowman, Dickey, Emmons, Grant, McIntosh and 1 more	66 min
May 17, 2:23 PM CDT	Severe Thunderstorm Watch	SPC	Bennett, Butte, Corson, Custer, Dewey, Fall River and 17 more	10 hr

Nearby

Mesoscale Discussions in South Dakota, 2018 Mesoscale Discussions in North 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.