Alert archive / Nebraska / Mesoscale Discussions in 2004

Mesoscale Discussion 1636

July 12, 200420 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 12, 2004, 7:45 PM CDT for 20 counties in Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 12, 2004, 7:45 PM CDT (00:45 UTC)
Expired: Jul 12, 2004, 9:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Boone County, NE, Butler County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Greeley County, NE, Hamilton County, NE, Howard County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Platte County, NE, Polk County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Valley County, NE, Wheeler County, NE, York County, NE

The radar

The Omaha radar (KOAX), 125 km from the middle of the area, began a volume at 00:48 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

Omaha, NE (KOAX), launched 00:00Z, 0.8 hours before the alert went out and 125 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: 4686 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 1125 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 101 m²/s²
0-3 km storm-relative helicity: 194 m²/s²
Significant tornado parameter: 3.2
Supercell composite: 20.9

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 12, 8:40 PM CDT	Tornado Watch	SPC	Adams, Buffalo, Clay, Franklin, Hall, Hamilton and 10 more	5 hr
Jul 12, 9:15 PM CDT	Severe Thunderstorm Watch	SPC	Cass, Douglas, Gage, Jefferson, Johnson, Lancaster and 7 more	7 hr
Jul 12, 11:19 PM CDT	Mesoscale Discussion	SPC	Adams, Butler, Cass, Clay, Dodge, Douglas and 18 more	116 min
Jul 13, 2:25 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Burt, Butler, Cass, Colfax, Cuming and 16 more	6 hr
Jul 13, 3:27 PM CDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Chase, Cheyenne, Deuel and 11 more	3 hr
Jul 13, 4:10 PM CDT	Severe Thunderstorm Watch	SPC	Arthur, Banner, Box Butte, Chase, Cheyenne, Dawes and 10 more	6 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; radar from the NEXRAD Level II archive.