Alert archive / Nebraska / Mesoscale Discussions in 2004

Mesoscale Discussion 393

April 20, 200411 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2004, 5:12 PM CDT for 11 counties in Nebraska. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Apr 20, 2004, 5:12 PM CDT (22:12 UTC)
Expired: Apr 20, 2004, 7:45 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center

Counties Antelope County, NE, Boone County, NE, Garfield County, NE, Holt County, NE, Knox County, NE, Madison County, NE, Pierce County, NE, Rock County, NE, Stanton County, NE, Wayne County, NE, Wheeler County, NE

The watches that followed

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

Severe Thunderstorm Watch 96Apr 20, 6:25 PM CDT

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.2 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: 13 J/kg
Mixed-layer CIN: -209 J/kg
Mixed-layer LCL: 546 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 74 m²/s²
0-3 km storm-relative helicity: 105 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.2

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
Apr 20, 12:05 PM CDT	Mesoscale Discussion	SPC	Boyd, Keya Paha	85 min
Apr 20, 6:25 PM CDT	Severe Thunderstorm Watch	SPC	Antelope, Boone, Burt, Butler, Cass, Cedar and 20 more	5 hr

Nearby

Mesoscale Discussions in Nebraska, 2004 Every mesoscale discussion in 2004

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.