Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 808

May 21, 200425 counties in Illinois; 54 counties in Iowa; Lafayette County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 21, 2004, 7:37 PM CDT for 25 counties in Illinois; 54 counties in Iowa; Lafayette County, Wisconsin. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
May 21, 2004, 7:37 PM CDT (00:37 UTC)
Expired
May 21, 2004, 9:00 PM CDT
In force
83 min
Issued by
the Storm Prediction Center
All 80 counties

Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cedar County, IA, Cherokee County, IA, Clay County, IA, Clayton County, IA, Clinton County, IA, Crawford County, IA, Dallas County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Humboldt County, IA, Ida County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Muscatine County, IA, O'Brien County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Poweshiek County, IA, Sac County, IA, Scott County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Washington County, IA, Webster County, IA, Wright County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henry County, IL, Iroquois County, IL, Jo Daviess County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, Mercer County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Lafayette County, WI

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 00:00Z, 0.6 hours before the alert went out and 346 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 00:00Z on 2004-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 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, Minneapolis, MN at 00:00Z on 2004-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 215 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
2 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
512 m above ground
0-6 km bulk shear
74 kt
0-1 km storm-relative helicity
215 m²/s²
0-3 km storm-relative helicity
257 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

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 22, 12:05 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 22 more6 hr
May 22, 2:41 AM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 23 more94 min
May 22, 6:58 AM CDTMesoscale DiscussionSPCAdams, Brown, Cass, Fulton, Hancock, Henderson and 13 more62 min
May 22, 11:03 AM CDTMesoscale DiscussionSPCDeWitt, Ford, Grundy, Iroquois, Kankakee, LaSalle and 9 more57 min
May 22, 11:35 AM CDTSevere Thunderstorm WatchSPCChampaign, Cook, DeWitt, Douglas, Ford, Grundy and 10 more6 hr
May 22, 5:52 PM CDTMesoscale DiscussionSPCBureau, Carroll, DeKalb, Grundy, Henry, Jo Daviess and 12 more113 min
May 22, 6:15 PM CDTTornado WatchSPCBoone, Bureau, Carroll, DeKalb, DuPage, Grundy and 25 more6 hr
May 21, 9:55 PM CDTTornado WatchSPCAudubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 14 more4 hr
May 22, 12:25 AM CDTMesoscale DiscussionSPCAudubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 14 more2 hr
May 22, 12:55 AM CDTSevere Thunderstorm WatchSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 17 more5 hr
May 22, 3:44 AM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Boone, Cass, Dallas and 11 more61 min
May 22, 3:02 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Cass, Clarke and 29 more58 min
May 22, 3:45 PM CDTTornado WatchSPCFremont, Harrison, Mills, Pottawattamie, Shelby7 hr

Nearby

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