Alert archive / Nebraska / Mesoscale Discussions in 2017

Mesoscale Discussion 468

April 9, 201714 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2017, 5:35 PM CDT for 14 counties in Nebraska. It was in force for 25 min.

The area

The outline as issued.

The facts

Issued: Apr 9, 2017, 5:35 PM CDT (22:35 UTC)
Expired: Apr 9, 2017, 6:00 PM CDT
In force: 25 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

Counties Adams County, NE, Buffalo County, NE, Clay County, NE, Dawson County, NE, Fillmore County, NE, Franklin County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Kearney County, NE, Phelps County, NE, Polk County, NE, Webster County, NE, York County, NE

The radar

The Grand Island radar (KUEX), 41 km from the middle of the area, began a volume at 22:35 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 134Apr 9, 5:40 PM CDT

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 10.6 hours before the alert went out and 167 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1407 m above ground
0-6 km bulk shear: 66 kt
0-1 km storm-relative helicity: 266 m²/s²
0-3 km storm-relative helicity: 305 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
Apr 9, 2:20 PM CDT	Mesoscale Discussion	SPC	Adams, Arthur, Blaine, Buffalo, Chase, Custer and 27 more	2 hr
Apr 9, 5:44 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Buffalo, Clay, Dawson, Fillmore, Franklin and 12 more	3 hr

Nearby

Mesoscale Discussions in Nebraska, 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.