Alert archive / Nebraska / Mesoscale Discussions in 2004

Mesoscale Discussion 807

May 21, 20044 states

The Storm Prediction Center issued this mesoscale discussion at May 21, 2004, 6:33 PM CDT for 4 states. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued: May 21, 2004, 6:33 PM CDT (23:33 UTC)
Expired: May 21, 2004, 7:30 PM CDT
In force: 57 min
Issued by: the Storm Prediction Center

All 76 counties

Lyon County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Rock County, MN, Adams County, NE, Antelope County, NE, Boone County, NE, Boyd County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cedar County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Fillmore County, NE, Franklin County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Holt County, NE, Howard County, NE, Jefferson County, NE, Kearney County, NE, Knox County, NE, Lancaster County, NE, Loup County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nuckolls County, NE, Phelps County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Saline County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thayer County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Webster County, NE, Wheeler County, NE, York County, NE, Aurora County, SD, Bon Homme County, SD, Brule County, SD, Charles Mix County, SD, Clay County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, Lake County, SD, Lincoln County, SD, McCook County, SD, Miner County, SD, Minnehaha County, SD, Moody County, SD, Sanborn County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Omaha radar (KOAX), 160 km from the middle of the area, began a volume at 23:33 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 12:00Z, 11.6 hours before the alert went out and 160 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: 718 J/kg
Mixed-layer CIN: -227 J/kg
Mixed-layer LCL: 1161 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 160 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.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 7:32 PM CDT	Mesoscale Discussion	SPC	Cedar, Clinton, Des Moines, Henry, Jefferson, Keokuk and 5 more	88 min
May 20, 10:03 PM CDT	Mesoscale Discussion	SPC	Fremont, Harrison, Mills, Pottawattamie	87 min
May 21, 1:11 AM CDT	Mesoscale Discussion	SPC	Audubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 27 more	34 min
May 21, 1:20 AM CDT	Severe Thunderstorm Watch	SPC	Audubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 19 more	6 hr
May 21, 2:22 AM CDT	Mesoscale Discussion	SPC	Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 47 more	23 min
May 21, 2:35 AM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 22 more	4 hr
May 21, 4:34 AM CDT	Mesoscale Discussion	SPC	Allamakee, Black Hawk, Bremer, Buchanan, Buena Vista, Butler and 35 more	56 min
May 21, 6:23 AM CDT	Mesoscale Discussion	SPC	Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clay and 20 more	67 min
May 21, 9:44 AM CDT	Mesoscale Discussion	SPC	Allamakee, Benton, Black Hawk, Bremer, Buchanan, Buena Vista and 38 more	3 hr
May 21, 10:25 AM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 37 more	6 hr
May 21, 1:59 PM CDT	Mesoscale Discussion	SPC	Benton, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 9 more	2 hr
May 21, 2:45 PM CDT	Tornado Watch	SPC	Allamakee, Audubon, Benton, Black Hawk, Boone, Bremer and 59 more	7 hr
May 21, 2:20 AM CDT	Severe Thunderstorm Watch	SPC	Blue Earth, Brown, Cottonwood, Dodge, Faribault, Fillmore and 20 more	5 hr
May 20, 10:30 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Buffalo, Butler, Chase, Clay, Colfax and 32 more	6 hr
May 21, 2:22 PM CDT	Mesoscale Discussion	SPC	Banner, Box Butte, Cheyenne, Dawes, Kimball, Morrill and 3 more	113 min
May 21, 3:05 PM CDT	Severe Thunderstorm Watch	SPC	Arthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 8 more	5 hr
May 21, 4:57 PM CDT	Mesoscale Discussion	SPC	Blaine, Brown, Cherry, Hooker, Keya Paha, Logan and 2 more	93 min
May 21, 5:35 PM CDT	Mesoscale Discussion	SPC	Adams, Antelope, Boone, Buffalo, Burt, Butler and 35 more	115 min

Nearby

Mesoscale Discussions in Nebraska, 2004 Mesoscale Discussions in South Dakota, 2004 Mesoscale Discussions in Iowa, 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.