Alert archive / South Dakota / Mesoscale Discussions in 2018

Mesoscale Discussion 1002

July 3, 2018Carter County, Montana; 13 counties in South Dakota; Crook County, Niobrara County, Weston County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jul 3, 2018, 8:38 PM MDT for Carter County, Montana; 13 counties in South Dakota; Crook County, Niobrara County, Weston County, Wyoming. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 3, 2018, 8:38 PM MDT (02:38 UTC)
Expired: Jul 3, 2018, 10:45 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Carter County, MT, Bennett County, SD, Butte County, SD, Custer County, SD, Fall River County, SD, Haakon County, SD, Harding County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Ziebach County, SD, Crook County, WY, Niobrara County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 105 km from the middle of the area, began a volume at 02:40 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 nearest sounding before it

Rapid City, SD (KRAP), launched 00:00Z, 2.6 hours before the alert went out and 108 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: 931 J/kg
Mixed-layer CIN: -300 J/kg
Mixed-layer LCL: 1369 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 226 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

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, 8:13 PM MDT	Mesoscale Discussion	SPC	Custer, Dawson, Fallon, McCone, Prairie, Richland and 3 more	2 hr
Jul 3, 8:39 PM MDT	Severe Thunderstorm Watch	SPC	Dawson, McCone, Richland, Roosevelt, Sheridan, Wibaux	6 hr
Jul 3, 9:38 PM MDT	Mesoscale Discussion	SPC	Brown, Campbell, Clark, Corson, Day, Dewey and 14 more	97 min
Jul 3, 10:02 PM MDT	Severe Thunderstorm Watch	SPC	Brown, Campbell, Clark, Corson, Day, Dewey and 13 more	6 hr
Jul 4, 2:14 AM MDT	Mesoscale Discussion	SPC	Beadle, Brown, Clark, Codington, Day, Edmunds and 14 more	91 min
Jul 4, 1:01 PM MDT	Mesoscale Discussion	SPC	Bon Homme, Charles Mix, Clay, Gregory, Union, Yankton	119 min
Jul 4, 4:35 PM MDT	Mesoscale Discussion	SPC	Bon Homme, Clay, Union, Yankton	115 min
Jul 4, 1:51 PM MDT	Mesoscale Discussion	SPC	Albany, Goshen, Laramie	54 min

Nearby

Mesoscale Discussions in South Dakota, 2018 Mesoscale Discussions in Wyoming, 2018 Mesoscale Discussions in Montana, 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.