Alert archive / Nebraska / Mesoscale Discussions in 2004

Mesoscale Discussion 399

April 20, 20048 counties in Iowa; Atchison County, Missouri; 26 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2004, 8:06 PM CDT for 8 counties in Iowa; Atchison County, Missouri; 26 counties in Nebraska. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2004, 8:06 PM CDT (01:06 UTC)
Expired
Apr 20, 2004, 9:30 PM CDT
In force
84 min
Issued by
the Storm Prediction Center
All 35 counties

Fremont County, IA, Harrison County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA, Atchison County, MO, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Nance County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Sarpy County, NE, Saunders County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 1.1 hours before the alert went out and 6 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-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2004-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 88 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2004-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
88 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
2225 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
40 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.

IssuedProductOfficeCountiesLasted
Apr 20, 7:20 PM CDTMesoscale DiscussionSPCAppanoose, Clarke, Dallas, Davis, Decatur, Henry and 19 more115 min
Apr 21, 3:04 PM CDTMesoscale DiscussionSPCHarrison, Lyon, Monona, Plymouth, Sioux, Woodbury2 hr
Apr 20, 7:22 PM CDTMesoscale DiscussionSPCBarry, Barton, Cedar, Dade, Jasper, Lawrence and 4 more23 min
Apr 20, 7:50 PM CDTTornado WatchSPCBarry, McDonald, Stone, Taney5 hr
Apr 20, 8:57 PM CDTMesoscale DiscussionSPCBarry, McDonald, Stone, Taney2 hr
Apr 20, 9:38 PM CDTMesoscale DiscussionSPCAudrain, Boone, Callaway, Cole, Crawford, Dent and 16 more37 min
Apr 20, 10:57 PM CDTMesoscale DiscussionSPCBarry, McDonald, Stone, Taney93 min
Apr 20, 11:10 PM CDTMesoscale DiscussionSPCCrawford, Dent, Franklin, Gasconade, Iron, Jefferson and 9 more2 hr
Apr 21, 2:58 PM CDTMesoscale DiscussionSPCBollinger, Butler, Cape Girardeau, Mississippi, New Madrid, Pemiscot and 4 more92 min

Nearby

Mesoscale Discussions in Nebraska, 2004Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in Missouri, 2004Every 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.