Alert archive / Nebraska / Mesoscale Discussions in 2015

Mesoscale Discussion 1687

August 15, 201513 counties in Nebraska; 9 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2015, 6:01 PM MDT for 13 counties in Nebraska; 9 counties in South Dakota. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Aug 15, 2015, 6:01 PM MDT (00:01 UTC)
Expired: Aug 15, 2015, 7:30 PM MDT
In force: 89 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 22 counties

Arthur County, NE, Boyd County, NE, Brown County, NE, Cherry County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keya Paha County, NE, McPherson County, NE, Morrill County, NE, Rock County, NE, Sheridan County, NE, Thomas County, NE, Aurora County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Gregory County, SD, Jerauld County, SD, Lyman County, SD, Todd County, SD, Tripp County, SD

The radar

The North Platte radar (KLNX), 102 km from the middle of the area, began a volume at 00:02 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

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 0.0 hours before the alert went out and 194 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: 2275 J/kg
Mixed-layer CIN: -75 J/kg
Mixed-layer LCL: 1872 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 305 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 8.8

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 16, 12:08 PM MDT	Mesoscale Discussion	SPC	Kimball	3 hr
Aug 16, 1:42 PM MDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Dawson, Franklin, Frontier and 15 more	2 hr
Aug 16, 3:01 PM MDT	Mesoscale Discussion	SPC	Burt, Cedar, Cuming, Dakota, Dixon, Dodge and 3 more	119 min
Aug 16, 5:24 PM MDT	Mesoscale Discussion	SPC	Banner, Box Butte, Scotts Bluff, Sioux	2 hr

Nearby

Mesoscale Discussions in Nebraska, 2015 Mesoscale Discussions in South Dakota, 2015 Every mesoscale discussion in 2015

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.