Alert archive / Louisiana / Mesoscale Discussions in 2013

Mesoscale Discussion 4

January 9, 201311 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Jan 9, 2013, 6:18 PM CST for 11 parishes in Louisiana. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jan 9, 2013, 6:18 PM CST (00:18 UTC)
Expired: Jan 9, 2013, 8:15 PM CST
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Assumption Parish, LA, Iberia Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 0.3 hours before the alert went out and 149 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: 196 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 447 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 225 m²/s²
0-3 km storm-relative helicity: 292 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

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
Jan 10, 4:05 AM CST	Mesoscale Discussion	SPC	Acadia, Avoyelles, Concordia, Evangeline, Iberia, Iberville and 7 more	85 min
Jan 10, 4:31 AM CST	Tornado Watch	SPC	Acadia, Ascension, Assumption, Avoyelles, Catahoula, Concordia and 16 more	6 hr
Jan 10, 5:47 AM CST	Mesoscale Discussion	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 4 more	58 min
Jan 10, 6:14 AM CST	Tornado Watch	SPC	Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana, Iberville and 17 more	11 hr
Jan 10, 7:36 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Jefferson, Lafourche and 12 more	84 min
Jan 10, 11:35 AM CST	Mesoscale Discussion	SPC	Orleans, Plaquemines, Saint Bernard	85 min

Nearby

Mesoscale Discussions in Louisiana, 2013 Every 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.