Alert archive / Nebraska / Mesoscale Discussions in 2007

Mesoscale Discussion 1531

July 18, 200751 counties in Nebraska; 10 counties in South Dakota; Crook County, Niobrara County, Weston County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2007, 7:15 PM CDT for 51 counties in Nebraska; 10 counties in South Dakota; Crook County, Niobrara County, Weston County, Wyoming. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: Jul 18, 2007, 7:15 PM CDT (00:15 UTC)
Expired: Jul 18, 2007, 8:45 PM CDT
In force: 90 min
Issued by: the Storm Prediction Center

All 64 counties

Adams County, NE, Antelope County, NE, Arthur County, NE, Blaine County, NE, Boone County, NE, Box Butte County, NE, Brown County, NE, Buffalo County, NE, Butler County, NE, Cherry County, NE, Clay County, NE, Custer County, NE, Dawes County, NE, Dawson County, NE, Deuel County, NE, Fillmore County, NE, Frontier County, NE, Garden County, NE, Garfield County, NE, Gosper County, NE, Grant County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Hayes County, NE, Holt County, NE, Hooker County, NE, Howard County, NE, Kearney County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, Madison County, NE, McPherson County, NE, Merrick County, NE, Morrill County, NE, Nance County, NE, Perkins County, NE, Phelps County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Seward County, NE, Sheridan County, NE, Sherman County, NE, Sioux County, NE, Thomas County, NE, Valley County, NE, Wheeler County, NE, York County, NE, Bennett County, SD, Butte County, SD, Custer County, SD, Fall River County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Todd County, SD, Crook County, WY, Niobrara County, WY, Weston County, WY

The radar

The North Platte radar (KLNX), 137 km from the middle of the area, began a volume at 00:16 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.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 0.3 hours before the alert went out and 215 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: 3120 J/kg
Mixed-layer CIN: -38 J/kg
Mixed-layer LCL: 2085 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 98 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.7

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
Jul 18, 8:39 PM CDT	Severe Thunderstorm Watch	SPC	Antelope, Arthur, Blaine, Boone, Boyd, Brown and 45 more	7 hr
Jul 18, 10:23 PM CDT	Mesoscale Discussion	SPC	Burt, Cedar, Cuming, Dakota, Dixon, Dodge and 6 more	97 min
Jul 18, 10:39 PM CDT	Severe Thunderstorm Watch	SPC	Douglas, Sarpy, Saunders, Washington	5 hr
Jul 19, 1:41 AM CDT	Mesoscale Discussion	SPC	Douglas, Sarpy, Saunders, Washington	94 min
Jul 19, 1:01 PM CDT	Mesoscale Discussion	SPC	Albany, Laramie, Platte	3 hr
Jul 19, 2:46 PM CDT	Mesoscale Discussion	SPC	Big Horn, Campbell, Johnson, Sheridan, Washakie	2 hr

Nearby

Mesoscale Discussions in Nebraska, 2007 Mesoscale Discussions in South Dakota, 2007 Mesoscale Discussions in Wyoming, 2007 Every mesoscale discussion in 2007

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.