Alert archive / Nebraska / Mesoscale Discussions in 2017

Mesoscale Discussion 1580

August 26, 201719 counties in Nebraska; 8 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 26, 2017, 6:40 PM MDT for 19 counties in Nebraska; 8 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 26, 2017, 6:40 PM MDT (00:40 UTC)
Expired: Aug 26, 2017, 8:45 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 27 counties

Arthur County, NE, Blaine County, NE, Brown County, NE, Cherry County, NE, Custer County, NE, Dawson County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Hayes County, NE, Hooker County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Perkins County, NE, Sheridan County, NE, Thomas County, NE, Bennett County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Mellette County, SD, Oglala Lakota County, SD, Stanley County, SD, Todd County, SD

The radar

The North Platte radar (KLNX), 38 km from the middle of the area, began a volume at 00:39 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, 0.7 hours before the alert went out and 119 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: 557 J/kg
Mixed-layer CIN: -125 J/kg
Mixed-layer LCL: 2379 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 212 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

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
Aug 27, 12:15 AM MDT	Mesoscale Discussion	SPC	Blaine, Cherry, Custer, Hooker, Logan, McPherson and 1 more	60 min
Aug 27, 4:13 AM MDT	Mesoscale Discussion	SPC	Jefferson, Thayer	62 min

Nearby

Mesoscale Discussions in Nebraska, 2017 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.