Alert archive / Illinois / Mesoscale Discussions in 2013

Mesoscale Discussion 729

May 20, 201327 counties in Illinois; 7 counties in Indiana; 8 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 20, 2013, 3:27 PM CDT for 27 counties in Illinois; 7 counties in Indiana; 8 counties in Missouri. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued
May 20, 2013, 3:27 PM CDT (20:27 UTC)
Expired
May 20, 2013, 4:30 PM CDT
In force
63 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 42 counties

Brown County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, DeWitt County, IL, Douglas County, IL, Ford County, IL, Greene County, IL, Iroquois County, IL, Jersey County, IL, Kankakee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Pike County, IL, Sangamon County, IL, Scott County, IL, Vermilion County, IL, Benton County, IN, Fountain County, IN, Jasper County, IN, Newton County, IN, Tippecanoe County, IN, Warren County, IN, White County, IN, Audrain County, MO, Lincoln County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO

The radar

The Lincoln radar (KILX), 31 km from the middle of the area, began a volume at 20:27 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

Davenport, (KDVN), launched 12:00Z, 8.5 hours before the alert went out and 215 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 12:00Z on 2013-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 12:00Z on 2013-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 231 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
4 J/kg
Mixed-layer CIN
-260 J/kg
Mixed-layer LCL
1298 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
231 m²/s²
0-3 km storm-relative helicity
256 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 19, 7:13 PM CDTMesoscale DiscussionSPCHancock, Henderson, Henry, Mercer, Rock Island, Warren62 min
May 19, 7:46 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Henry, Jo Daviess, Knox and 11 more59 min
May 19, 8:10 PM CDTTornado WatchSPCBoone, Bureau, Carroll, DeKalb, Fulton, Hancock and 25 more6 hr
May 19, 10:16 PM CDTMesoscale DiscussionSPCAdams, Brown, Pike59 min
May 19, 10:58 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, Fulton, Hancock and 22 more62 min
May 20, 5:07 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Greene, Jersey and 9 more23 min
May 20, 5:24 PM CDTTornado WatchSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 31 more7 hr
May 20, 6:35 PM CDTSevere Thunderstorm WatchSPCHenderson, Mercer, Warren5 hr
May 19, 7:55 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, Clay, Clinton, DeKalb and 4 more65 min
May 19, 11:49 PM CDTMesoscale DiscussionSPCBarry, Barton, Camden, Cedar, Christian, Dade and 17 more56 min
May 20, 8:46 AM CDTMesoscale DiscussionSPCBates, Benton, Cass, Henry, Jackson, Johnson and 4 more59 min
May 20, 12:26 PM CDTMesoscale DiscussionSPCBarry, Barton, Bates, Benton, Camden, Cedar and 20 more2 hr
May 20, 12:46 PM CDTTornado WatchSPCBarry, Barton, Bates, Benton, Boone, Callaway and 41 more8 hr
May 20, 5:38 PM CDTMesoscale DiscussionSPCAndrew, DeKalb, Gentry, Harrison, Worth67 min
May 20, 6:53 PM CDTMesoscale DiscussionSPCCarter, Dent, Douglas, Howell, Iron, Madison and 8 more67 min

Nearby

Mesoscale Discussions in Illinois, 2013Mesoscale Discussions in Missouri, 2013Mesoscale Discussions in Indiana, 2013Every mesoscale discussion in 2013

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.