Alert archive / Nebraska / Mesoscale Discussions in 2018

Mesoscale Discussion 1472

September 17, 201822 counties in Nebraska; 4 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Sep 17, 2018, 7:49 PM CDT for 22 counties in Nebraska; 4 counties in South Dakota. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued: Sep 17, 2018, 7:49 PM CDT (00:49 UTC)
Expired: Sep 17, 2018, 9:45 PM CDT
In force: 116 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 26 counties

Antelope County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Cedar County, NE, Cherry County, NE, Garfield County, NE, Grant County, NE, Holt County, NE, Hooker County, NE, Keya Paha County, NE, Knox County, NE, Logan County, NE, Loup County, NE, Madison County, NE, Pierce County, NE, Rock County, NE, Thomas County, NE, Valley County, NE, Wayne County, NE, Wheeler County, NE, Bon Homme County, SD, Charles Mix County, SD, Gregory County, SD, Yankton County, SD

The radar

The North Platte radar (KLNX), 69 km from the middle of the area, began a volume at 00:49 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, 0.8 hours before the alert went out and 146 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: 669 J/kg
Mixed-layer CIN: -74 J/kg
Mixed-layer LCL: 2738 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: 34 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

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
Sep 18, 3:06 PM CDT	Mesoscale Discussion	SPC	Butler, Cass, Colfax, Dodge, Douglas, Lancaster and 7 more	84 min
Sep 18, 5:11 PM CDT	Mesoscale Discussion	SPC	Cass, Sarpy	64 min
Sep 18, 2:48 AM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brookings, Brule, Buffalo, Charles Mix and 17 more	2 hr
Sep 18, 5:48 AM CDT	Mesoscale Discussion	SPC	Deuel, Minnehaha, Moody	2 hr

Nearby

Mesoscale Discussions in Nebraska, 2018 Mesoscale Discussions in South 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.