Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 843

May 23, 20044 states

The Storm Prediction Center issued this mesoscale discussion at May 23, 2004, 12:25 PM CDT for 4 states. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
May 23, 2004, 12:25 PM CDT (17:25 UTC)
Expired
May 23, 2004, 2:00 PM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 88 counties

Cedar County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Adams County, IL, Brown County, IL, Bureau County, IL, Calhoun County, IL, Carroll County, IL, Cass County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jersey County, IL, Jo Daviess County, IL, Knox County, IL, Lee County, IL, Macoupin County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Ogle County, IL, Peoria County, IL, Pike County, IL, Putnam County, IL, Rock Island County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Winnebago County, IL, Woodford County, IL, Audrain County, MO, Benton County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, City of Saint Louis, MO, Clark County, MO, Cole County, MO, Cooper County, MO, Dallas County, MO, Franklin County, MO, Gasconade County, MO, Hickory County, MO, Howard County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Maries County, MO, Marion County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Morgan County, MO, Osage County, MO, Pettis County, MO, Pike County, MO, Polk County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Louis County, MO, Shelby County, MO, St. Clair County, MO, Warren County, MO, Green County, WI, Lafayette County, WI, Rock County, WI

The radar

The St Louis radar (KLSX), 160 km from the middle of the area, began a volume at 17:28 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, 5.4 hours before the alert went out and 245 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 2004-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 435 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 2004-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 square meters per square second.19395878Sfc1 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
435 J/kg
Mixed-layer CIN
-95 J/kg
Mixed-layer LCL
621 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

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, 8:58 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, DuPage, Grundy and 23 more92 min
May 23, 12:24 AM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 32 more66 min
May 23, 12:40 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 27 more5 hr
May 23, 1:21 AM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Greene, Jersey and 6 more24 min
May 23, 1:40 AM CDTSevere Thunderstorm WatchSPCAdams, Brown, Cass, Fulton, Hancock, Logan and 8 more4 hr
May 23, 4:30 AM CDTMesoscale DiscussionSPCAdams, Boone, Brown, Bureau, Carroll, Cass and 44 more60 min
May 23, 10:45 AM CDTTornado WatchSPCClark, Clay, Coles, Crawford, Cumberland, Edgar and 19 more5 hr
May 23, 12:45 PM CDTMesoscale DiscussionSPCClark, Clay, Coles, Crawford, Cumberland, Edgar and 18 more2 hr
May 23, 1:15 PM CDTTornado WatchSPCAdams, Brown, Calhoun, Cass, Fulton, Greene and 16 more6 hr
May 23, 2:05 PM CDTTornado WatchSPCBoone, Bureau, Carroll, DeKalb, DuPage, Grundy and 18 more8 hr
May 23, 2:53 PM CDTMesoscale DiscussionSPCIroquois, Vermilion67 min
May 23, 3:50 PM CDTTornado WatchSPCCook, DuPage, Iroquois, Kankakee, Vermilion, Will6 hr
May 23, 4:35 PM CDTSevere Thunderstorm WatchSPCMonroe5 hr
May 23, 5:00 PM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 28 more2 hr
May 23, 5:10 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, DuPage, Grundy and 17 more95 min
May 23, 5:30 PM CDTTornado WatchSPCBond, Calhoun, Christian, Clark, Clay, Clinton and 29 more6 hr
May 23, 6:30 PM CDTMesoscale DiscussionSPCCook, DuPage, Iroquois, Kankakee, Vermilion, Will2 hr
May 22, 7:11 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Clarke, Dallas and 15 more94 min
May 22, 7:23 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Dallas, Fremont and 9 more67 min
May 22, 10:40 PM CDTTornado WatchSPCAdair, Adams, Appanoose, Benton, Cedar, Clarke and 33 more5 hr
May 22, 11:33 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Benton, Cedar, Clarke and 33 more87 min
May 23, 2:21 AM CDTMesoscale DiscussionSPCAppanoose, Buchanan, Cedar, Davis, Delaware, Des Moines and 14 more54 min

Nearby

Mesoscale Discussions in Illinois, 2004Mesoscale Discussions in Missouri, 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.