Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 818

May 22, 200415 counties in Illinois; 13 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at May 22, 2004, 11:03 AM CDT for 15 counties in Illinois; 13 counties in Indiana. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
May 22, 2004, 11:03 AM CDT (16:03 UTC)
Expired
May 22, 2004, 12:00 PM CDT
In force
57 min
Issued by
the Storm Prediction Center
All 28 counties

DeWitt County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kankakee County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McLean County, IL, Putnam County, IL, Tazewell County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Cass County, IN, Fulton County, IN, Jasper County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, White County, IN

The radar

The Chicago radar (KLOT), 103 km from the middle of the area, began a volume at 16:02 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

Lincoln, IL (KILX), launched 12:00Z, 4.1 hours before the alert went out and 65 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, Lincoln, IL at 12:00Z on 2004-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 454 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, Lincoln, IL at 12:00Z on 2004-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 248 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
454 J/kg
Mixed-layer CIN
-171 J/kg
Mixed-layer LCL
1064 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
248 m²/s²
0-3 km storm-relative helicity
281 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.5

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 21, 7:37 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, DuPage, Grundy and 19 more83 min
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, 11:35 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 22, 1:48 AM CDTMesoscale DiscussionSPCAllen, DeKalb, Elkhart, Kosciusko, LaGrange, LaPorte and 4 more57 min
May 22, 2:36 PM CDTMesoscale DiscussionSPCAdams, Allen, Blackford, Carroll, Cass, Clinton and 17 more54 min
May 22, 3:20 PM CDTSevere Thunderstorm WatchSPCJay, Randolph8 hr
May 22, 5:29 PM CDTMesoscale DiscussionSPCJay, Randolph91 min

Nearby

Mesoscale Discussions in Illinois, 2004Mesoscale Discussions in Indiana, 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.