Alert archive / Illinois / Mesoscale Discussions in 2003

Mesoscale Discussion 807

May 6, 20034 states

The Storm Prediction Center issued this mesoscale discussion at May 6, 2003, 9:35 PM CDT for 4 states. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued
May 6, 2003, 9:35 PM CDT (02:35 UTC)
Expired
May 6, 2003, 11:30 PM CDT
In force
115 min
Issued by
the Storm Prediction Center
All 31 counties

Alexander County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Saline County, IL, Union County, IL, Washington County, IL, White County, IL, Williamson County, IL, Posey County, IN, Ballard County, KY, Crittenden County, KY, Henderson County, KY, Livingston County, KY, McCracken County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Cape Girardeau County, MO, Perry County, MO, Sainte Genevieve County, MO, Scott County, MO

The radar

The Paducah radar (KPAH), 72 km from the middle of the area, began a volume at 02:36 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

Nashville Metro, TN (KBNA), launched 00:00Z, 2.6 hours before the alert went out and 283 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, Nashville Metro, TN at 00:00Z on 2003-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1519 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, Nashville Metro, TN at 00:00Z on 2003-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 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
1519 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
720 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.9
Supercell composite
3.1

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 6, 7:03 PM CDTMesoscale DiscussionSPCClinton, Franklin, Hamilton, Jackson, Jefferson, Madison and 7 more117 min
May 6, 11:50 PM CDTTornado WatchSPCGallatin, Hamilton, Hardin, Johnson, Massac, Pope and 2 more6 hr
May 7, 12:42 PM CDTMesoscale DiscussionSPCChampaign, Clark, Clay, Coles, Crawford, Cumberland and 22 more2 hr
May 7, 1:16 AM CDTMesoscale DiscussionSPCHarrison3 hr
May 7, 1:41 AM CDTMesoscale DiscussionSPCFloyd, Harrison, Perry, Spencer3 hr
May 7, 6:06 PM CDTMesoscale DiscussionSPCAdams, Allen, Benton, Carroll, Cass, DeKalb and 20 more114 min
May 6, 11:32 PM CDTMesoscale DiscussionSPCBreckinridge, Butler, Caldwell, Calloway, Christian, Daviess and 18 more88 min
May 7, 2:40 AM CDTSevere Thunderstorm WatchSPCBell, Breathitt, Clark, Clay, Elliott, Estill and 27 more5 hr
May 7, 4:26 AM CDTMesoscale DiscussionSPCBell, Breathitt, Clark, Clay, Elliott, Estill and 27 more2 hr
May 7, 4:55 AM CDTTornado WatchSPCFulton6 hr
May 6, 7:53 PM CDTMesoscale DiscussionSPCButler, Carter, Howell, Oregon, Reynolds, Ripley and 2 more2 hr
May 6, 11:30 PM CDTTornado WatchSPCDunklin, Pemiscot6 hr
May 7, 2:27 AM CDTMesoscale DiscussionSPCDunklin, Pemiscot3 hr

Nearby

Mesoscale Discussions in Illinois, 2003Mesoscale Discussions in Kentucky, 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; radar from the NEXRAD Level II archive.