Alert archive / Nebraska / Mesoscale Discussions in 2015

Mesoscale Discussion 1773

September 7, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2015, 4:46 PM MDT for 4 states. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: Sep 7, 2015, 4:46 PM MDT (22:46 UTC)
Expired: Sep 7, 2015, 6:45 PM MDT
In force: 119 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 47 counties

Adams County, CO, Arapahoe County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Cheyenne County, KS, Arthur County, NE, Blaine County, NE, Brown County, NE, Chase County, NE, Cherry County, NE, Cheyenne County, NE, Custer County, NE, Dawson County, NE, Deuel County, NE, Dundy County, NE, Frontier County, NE, Garden County, NE, Grant County, NE, Hayes County, NE, Hitchcock County, NE, Hooker County, NE, Keith County, NE, Keya Paha County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Morrill County, NE, Perkins County, NE, Red Willow County, NE, Rock County, NE, Sheridan County, NE, Thomas County, NE, Bennett County, SD, Gregory County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Todd County, SD, Tripp County, SD

The radar

The Cheyenne radar (KCYS), 180 km from the middle of the area, began a volume at 22:47 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 507Sep 7, 5:50 PM MDT

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 10.8 hours before the alert went out and 174 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: 1107 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 111 m²/s²
0-3 km storm-relative helicity: 187 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
Sep 7, 5:50 PM MDT	Severe Thunderstorm Watch	SPC	Kit Carson, Yuma	2 hr
Sep 7, 1:18 PM MDT	Mesoscale Discussion	SPC	Brown, Cloud, Jewell, Marshall, Mitchell, Nemaha and 2 more	87 min
Sep 7, 2:37 PM MDT	Severe Thunderstorm Watch	SPC	Anderson, Brown, Clay, Cloud, Coffey, Dickinson and 17 more	6 hr
Sep 7, 5:23 PM MDT	Mesoscale Discussion	SPC	Chase, Clay, Cloud, Dickinson, Ellsworth, Geary and 18 more	97 min
Sep 7, 5:38 PM MDT	Severe Thunderstorm Watch	SPC	Allen, Butler, Chase, Greenwood, Marion, Woodson	3 hr
Sep 6, 7:42 PM MDT	Mesoscale Discussion	SPC	Cass, Douglas, Gage, Johnson, Lancaster, Nemaha and 4 more	93 min
Sep 6, 10:41 PM MDT	Mesoscale Discussion	SPC	Cass, Gage, Johnson, Lancaster, Nemaha, Otoe and 2 more	64 min

Nearby

Mesoscale Discussions in Nebraska, 2015 Mesoscale Discussions in Colorado, 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.