Alert archive / Nebraska / Mesoscale Discussions in 2004

Mesoscale Discussion 787

May 21, 20044 states

The Storm Prediction Center issued this mesoscale discussion at May 21, 2004, 1:11 AM CDT for 4 states. It was in force for 34 min.

The area

The outline as issued.

The facts

Issued
May 21, 2004, 1:11 AM CDT (06:11 UTC)
Expired
May 21, 2004, 1:45 AM CDT
In force
34 min
Issued by
the Storm Prediction Center
All 90 counties

Audubon County, IA, Boone County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Story County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Wright County, IA, Faribault County, MN, Jackson County, MN, Martin County, MN, Nobles County, MN, Rock County, MN, Antelope County, NE, Arthur County, NE, Blaine County, NE, Boone County, NE, Boyd County, NE, Brown County, NE, Burt County, NE, Cedar County, NE, Cherry County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Garfield County, NE, Grant County, NE, Greeley County, NE, Holt County, NE, Hooker County, NE, Keya Paha County, NE, Knox County, NE, Logan County, NE, Loup County, NE, Madison County, NE, McPherson County, NE, Pierce County, NE, Platte County, NE, Rock County, NE, Stanton County, NE, Thomas County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, Aurora County, SD, Bon Homme County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Lincoln County, SD, McCook County, SD, Minnehaha County, SD, Todd County, SD, Tripp County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The North Platte radar (KLNX), 176 km from the middle of the area, began a volume at 06:14 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, 6.2 hours before the alert went out and 221 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 2004-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 238 joules per kilogram.LCLLFCEL10008507005003002001001 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 2004-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 169 square meters per square second.193958Sfc1 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
238 J/kg
Mixed-layer CIN
-360 J/kg
Mixed-layer LCL
1260 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
169 m²/s²
0-3 km storm-relative helicity
462 m²/s²
Significant tornado parameter
0.0
Supercell composite
11.2

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.

IssuedProductOfficeCountiesLasted
May 20, 7:32 PM CDTMesoscale DiscussionSPCCedar, Clinton, Des Moines, Henry, Jefferson, Keokuk and 5 more88 min
May 20, 10:03 PM CDTMesoscale DiscussionSPCFremont, Harrison, Mills, Pottawattamie87 min
May 21, 1:20 AM CDTSevere Thunderstorm WatchSPCAudubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 19 more6 hr
May 21, 2:22 AM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 47 more23 min
May 21, 2:35 AM CDTSevere Thunderstorm WatchSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 22 more4 hr
May 21, 4:34 AM CDTMesoscale DiscussionSPCAllamakee, Black Hawk, Bremer, Buchanan, Buena Vista, Butler and 35 more56 min
May 21, 6:23 AM CDTMesoscale DiscussionSPCAllamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clay and 20 more67 min
May 21, 9:44 AM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Buena Vista and 38 more3 hr
May 21, 10:25 AM CDTSevere Thunderstorm WatchSPCAllamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 37 more6 hr
May 21, 1:59 PM CDTMesoscale DiscussionSPCBenton, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 9 more2 hr
May 21, 2:45 PM CDTTornado WatchSPCAllamakee, Audubon, Benton, Black Hawk, Boone, Bremer and 59 more7 hr
May 21, 6:33 PM CDTMesoscale DiscussionSPCLyon, Plymouth, Sioux, Woodbury57 min
May 21, 2:20 AM CDTSevere Thunderstorm WatchSPCBlue Earth, Brown, Cottonwood, Dodge, Faribault, Fillmore and 20 more5 hr
May 20, 10:30 PM CDTSevere Thunderstorm WatchSPCAdams, Buffalo, Butler, Chase, Clay, Colfax and 32 more6 hr
May 21, 2:22 PM CDTMesoscale DiscussionSPCBanner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 3 more113 min
May 21, 3:05 PM CDTSevere Thunderstorm WatchSPCArthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 8 more5 hr
May 21, 4:57 PM CDTMesoscale DiscussionSPCBlaine, Brown, Cherry, Hooker, Keya Paha, Logan and 2 more93 min
May 21, 5:35 PM CDTMesoscale DiscussionSPCAdams, Antelope, Boone, Buffalo, Burt, Butler and 35 more115 min

Nearby

Mesoscale Discussions in Nebraska, 2004Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in South Dakota, 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; radar from the NEXRAD Level II archive.