Alert archive / Nebraska / Mesoscale Discussions in 2018

Mesoscale Discussion 1297

August 15, 201825 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2018, 2:52 PM CDT for 25 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 15, 2018, 2:52 PM CDT (19:52 UTC)
Expired: Aug 15, 2018, 5:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 25 counties

Adams County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Buffalo County, NE, Custer County, NE, Dawson County, NE, Garfield County, NE, Gosper County, NE, Greeley County, NE, Hall County, NE, Holt County, NE, Hooker County, NE, Howard County, NE, Kearney County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Phelps County, NE, Rock County, NE, Sherman County, NE, Thomas County, NE, Valley County, NE, Wheeler County, NE

The radar

The North Platte radar (KLNX), 62 km from the middle of the area, began a volume at 19:51 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 12:00Z, 7.9 hours before the alert went out and 105 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: 19 J/kg
Mixed-layer CIN: -217 J/kg
Mixed-layer LCL: 1018 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 32 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
Aug 15, 9:03 AM CDT	Mesoscale Discussion	SPC	Keya Paha	2 hr
Aug 15, 6:02 PM CDT	Severe Thunderstorm Watch	SPC	Chase, Frontier, Hayes, Keith, Lincoln, Perkins	4 hr

Nearby

Mesoscale Discussions in Nebraska, 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.