Alert archive / Illinois / Mesoscale Discussions in 2014

Mesoscale Discussion 1693

September 9, 201417 counties in Illinois; City of Saint Louis, Missouri

The Storm Prediction Center issued this mesoscale discussion at Sep 9, 2014, 9:44 AM CDT for 17 counties in Illinois; City of Saint Louis, Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 9, 2014, 9:44 AM CDT (14:44 UTC)
Expired: Sep 9, 2014, 11:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Bond County, IL, Calhoun County, IL, Cass County, IL, Clinton County, IL, Greene County, IL, Jefferson County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Scott County, IL, Washington County, IL, City of Saint Louis, MO

The radar

The St Louis radar (KLSX), 69 km from the middle of the area, began a volume at 14:44 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 12:00Z, 2.7 hours before the alert went out and 185 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: 278 J/kg
Mixed-layer CIN: -148 J/kg
Mixed-layer LCL: 1161 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 167 m²/s²
0-3 km storm-relative helicity: 173 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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
Sep 9, 5:02 PM CDT	Mesoscale Discussion	SPC	Monroe, Saint Clair	88 min
Sep 9, 12:13 PM CDT	Mesoscale Discussion	SPC	Harrison, Mercer, Worth	62 min
Sep 9, 1:25 PM CDT	Mesoscale Discussion	SPC	Benton, Boone, Callaway, Camden, Carter, Christian and 40 more	2 hr
Sep 9, 3:06 PM CDT	Mesoscale Discussion	SPC	Andrew, Atchison, Buchanan, Caldwell, Clinton, Daviess and 8 more	114 min
Sep 9, 3:34 PM CDT	Tornado Watch	SPC	Adair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 15 more	8 hr
Sep 9, 5:06 PM CDT	Mesoscale Discussion	SPC	Andrew, Atchison, Buchanan, DeKalb, Gentry, Holt and 2 more	54 min
Sep 9, 6:45 PM CDT	Mesoscale Discussion	SPC	Andrew, Atchison, Gentry, Grundy, Harrison, Holt and 5 more	90 min

Nearby

Mesoscale Discussions in Illinois, 2014 Mesoscale Discussions in Missouri, 2014 Every mesoscale discussion in 2014

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.