Alert archive / Illinois / Mesoscale Discussions in 2003

Mesoscale Discussion 1929

July 20, 200335 counties in Illinois; 26 counties in Iowa; 20 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2003, 11:14 PM CDT for 35 counties in Illinois; 26 counties in Iowa; 20 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 20, 2003, 11:14 PM CDT (04:14 UTC)
Expired
Jul 21, 2003, 1:15 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 81 counties

Appanoose County, IA, Benton County, IA, Cedar County, IA, Clinton County, IA, Davis County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Adams County, IL, Brown County, IL, Cass County, IL, Champaign County, IL, DeWitt County, IL, Ford County, IL, Fulton County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Jo Daviess County, IL, Knox County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Rock Island County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Warren County, IL, Woodford County, IL, Adair County, MO, Carroll County, MO, Chariton County, MO, Clark County, MO, Grundy County, MO, Knox County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Marion County, MO, Monroe County, MO, Pike County, MO, Putnam County, MO, Ralls County, MO, Randolph County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 4.2 hours before the alert went out and 106 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, Davenport, at 00:00Z on 2003-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3041 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, Davenport, at 00:00Z on 2003-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 123 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
3041 J/kg
Mixed-layer CIN
-67 J/kg
Mixed-layer LCL
1003 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
123 m²/s²
0-3 km storm-relative helicity
251 m²/s²
Significant tornado parameter
1.5
Supercell composite
9.6

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
Jul 20, 8:08 PM CDTMesoscale DiscussionSPCBureau, Carroll, Fulton, Hancock, Henderson, Henry and 15 more2 hr
Jul 20, 8:30 PM CDTTornado WatchSPCCarroll, Henry, Jo Daviess, Mercer, Rock Island, Whiteside6 hr
Jul 20, 9:48 PM CDTMesoscale DiscussionSPCBoone, Bureau, Cook, DeKalb, DuPage, Grundy and 12 more117 min
Jul 20, 10:15 PM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Cook, DeKalb, DuPage, Grundy and 12 more7 hr
Jul 20, 11:30 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Cass, Champaign, DeWitt, Douglas and 21 more6 hr
Jul 21, 1:56 AM CDTMesoscale DiscussionSPCChampaign, Douglas, Edgar, Ford, Iroquois, Macon and 2 more2 hr
Jul 21, 4:12 AM CDTMesoscale DiscussionSPCClay, Crawford, Edwards, Effingham, Franklin, Hamilton and 7 more2 hr
Jul 21, 3:26 PM CDTMesoscale DiscussionSPCCook94 min
Jul 20, 7:49 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Calhoun, Carroll, Cass and 17 more56 min
Jul 20, 8:50 PM CDTTornado WatchSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 16 more5 hr
Jul 20, 7:05 PM CDTSevere Thunderstorm WatchSPCDouglas, Howell, Oregon, Ozark, Shannon5 hr
Jul 20, 10:43 PM CDTMesoscale DiscussionSPCHolt, Nodaway62 min

Nearby

Mesoscale Discussions in Illinois, 2003Mesoscale Discussions in Iowa, 2003Mesoscale Discussions in Missouri, 2003Every mesoscale discussion in 2003

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.