Alert archive / Nebraska / Mesoscale Discussions in 2011

Mesoscale Discussion 1330

June 20, 2011Decatur County, Norton County, Kansas; 4 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jun 20, 2011, 7:21 PM CDT for Decatur County, Norton County, Kansas; 4 counties in Nebraska. It was in force for 24 min.

The area

The outline as issued.

The facts

Issued: Jun 20, 2011, 7:21 PM CDT (00:21 UTC)
Expired: Jun 20, 2011, 7:45 PM CDT
In force: 24 min
Issued by: the Storm Prediction Center

Counties Decatur County, KS, Norton County, KS, Furnas County, NE, Gosper County, NE, Harlan County, NE, Phelps County, NE

The watches that followed

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

Tornado Watch 527Jun 20, 7:40 PM CDT

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 0.4 hours before the alert went out and 138 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: 109 J/kg
Mixed-layer CIN: -135 J/kg
Mixed-layer LCL: 552 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 271 m²/s²
0-3 km storm-relative helicity: 471 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
Jun 20, 7:40 PM CDT	Tornado Watch	SPC	Decatur, Graham, Jewell, Mitchell, Norton, Osborne and 4 more	3 hr
Jun 20, 7:46 PM CDT	Mesoscale Discussion	SPC	Allen, Anderson, Atchison, Bourbon, Brown, Chautauqua and 25 more	59 min
Jun 20, 8:32 PM CDT	Tornado Watch	SPC	Allen, Anderson, Atchison, Bourbon, Brown, Chautauqua and 25 more	4 hr
Jun 20, 9:46 PM CDT	Severe Thunderstorm Watch	SPC	Bourbon, Cherokee, Crawford	9 hr

Nearby

Mesoscale Discussions in Nebraska, 2011 Mesoscale Discussions in Kansas, 2011 Every mesoscale discussion in 2011

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.