Alert archive / Illinois / Mesoscale Discussions in 2015

Mesoscale Discussion 1373

July 11, 201524 counties in Illinois; 10 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jul 11, 2015, 9:57 PM CDT for 24 counties in Illinois; 10 counties in Missouri. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Jul 11, 2015, 9:57 PM CDT (02:57 UTC)
Expired: Jul 11, 2015, 11:30 PM CDT
In force: 93 min
Issued by: the Storm Prediction Center

All 34 counties

Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clinton County, IL, Fayette County, IL, Greene County, IL, Hancock County, IL, Jersey County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Pike County, IL, Saint Clair County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, City of Saint Louis, MO, Clark County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 77 km from the middle of the area, began a volume at 02:58 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 nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 3.0 hours before the alert went out and 178 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1094 J/kg
Mixed-layer CIN: -59 J/kg
Mixed-layer LCL: 865 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 240 m²/s²
0-3 km storm-relative helicity: 371 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 7.2

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.

Issued	Product	Office	Counties	Lasted
Jul 11, 8:00 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Calhoun, Christian, Clay, Clinton, Effingham and 20 more	6 hr

Nearby

Mesoscale Discussions in Illinois, 2015 Mesoscale Discussions in Missouri, 2015 Every mesoscale discussion in 2015

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.