Alert archive / Nebraska / Mesoscale Discussions in 2007

Mesoscale Discussion 1637

August 3, 200715 counties in Nebraska; 6 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2007, 4:49 PM MDT for 15 counties in Nebraska; 6 counties in South Dakota. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued: Aug 3, 2007, 4:49 PM MDT (22:49 UTC)
Expired: Aug 3, 2007, 6:45 PM MDT
In force: 116 min
Issued by: the Storm Prediction Center

All 21 counties

Arthur County, NE, Blaine County, NE, Brown County, NE, Cherry County, NE, Custer County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keya Paha County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Rock County, NE, Sheridan County, NE, Thomas County, NE, Bennett County, SD, Jackson County, SD, Mellette County, SD, Oglala Lakota County, SD, Todd County, SD, Tripp County, SD

The radar

The North Platte radar (KLNX), 107 km from the middle of the area, began a volume at 22:52 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, 10.8 hours before the alert went out and 190 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: 940 J/kg
Mixed-layer CIN: -29 J/kg
Mixed-layer LCL: 694 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 104 m²/s²
0-3 km storm-relative helicity: 116 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
Aug 3, 1:32 PM MDT	Mesoscale Discussion	SPC	Box Butte, Dawes, Grant, Morrill, Scotts Bluff, Sheridan and 1 more	2 hr
Aug 3, 2:17 PM MDT	Tornado Watch	SPC	Arthur, Blaine, Brown, Cherry, Custer, Garden and 9 more	8 hr

Nearby

Mesoscale Discussions in Nebraska, 2007 Mesoscale Discussions in South Dakota, 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.