Alert archive / Nebraska / Mesoscale Discussions in 2007

Mesoscale Discussion 1242

June 21, 20076 counties in Colorado; 17 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2007, 2:40 PM MDT for 6 counties in Colorado; 17 counties in Nebraska. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: Jun 21, 2007, 2:40 PM MDT (20:40 UTC)
Expired: Jun 21, 2007, 4:15 PM MDT
In force: 95 min
Issued by: the Storm Prediction Center

All 23 counties

Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Arthur County, NE, Chase County, NE, Cherry County, NE, Cheyenne County, NE, Deuel County, NE, Dundy County, NE, Garden County, NE, Grant County, NE, Hayes County, NE, Hitchcock County, NE, Hooker County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, McPherson County, NE, Perkins County, NE, Thomas County, NE

The radar

The North Platte radar (KLNX), 169 km from the middle of the area, began a volume at 20:44 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.

Tornado Watch 438Jun 21, 3:40 PM MDT

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 8.7 hours before the alert went out and 142 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: 1018 J/kg
Mixed-layer CIN: -479 J/kg
Mixed-layer LCL: 1694 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 99 m²/s²
0-3 km storm-relative helicity: 136 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Jun 21, 1:13 PM MDT	Mesoscale Discussion	SPC	Antelope, Boone, Boyd, Burt, Cedar, Cuming and 13 more	62 min
Jun 21, 2:15 PM MDT	Mesoscale Discussion	SPC	Boyd, Dakota, Dixon	30 min
Jun 21, 3:37 PM MDT	Tornado Watch	SPC	Arthur, Blaine, Box Butte, Brown, Chase, Cherry and 23 more	7 hr
Jun 21, 5:33 PM MDT	Mesoscale Discussion	SPC	Antelope, Boone, Boyd, Buffalo, Custer, Dawson and 19 more	87 min

Nearby

Mesoscale Discussions in Nebraska, 2007 Mesoscale Discussions in Colorado, 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.