Alert archive / Wisconsin / Mesoscale Discussions in 2004

Mesoscale Discussion 798

May 21, 200415 counties in Iowa; 16 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 21, 2004, 1:59 PM CDT for 15 counties in Iowa; 16 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 21, 2004, 1:59 PM CDT (18:59 UTC)
Expired
May 21, 2004, 4:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 31 counties

Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Delaware County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hamilton County, IA, Hardin County, IA, Marshall County, IA, Tama County, IA, Adams County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Grant County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Marquette County, WI, Richland County, WI, Sauk County, WI, Washington County, WI, Waushara County, WI, Winnebago County, WI

The radar

The La Crosse radar (KARX), 78 km from the middle of the area, began a volume at 18:58 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

Minneapolis, MN (KMPX), launched 12:00Z, 7.0 hours before the alert went out and 279 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, Minneapolis, MN at 12:00Z on 2004-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Minneapolis, MN at 12:00Z on 2004-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 216 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
732 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
216 m²/s²
0-3 km storm-relative helicity
321 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.

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, 1:11 AM CDTMesoscale DiscussionSPCAudubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 27 more34 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, 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, 9:40 AM CDTMesoscale DiscussionSPCKenosha2 hr
May 21, 3:00 PM CDTSevere Thunderstorm WatchSPCAdams, Calumet, Columbia, Dane, Dodge, Fond du Lac and 19 more7 hr
May 21, 5:35 PM CDTTornado WatchSPCLafayette5 hr

Nearby

Mesoscale Discussions in Wisconsin, 2004Mesoscale Discussions in Iowa, 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.