Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 3

January 3, 200932 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Jan 3, 2009, 7:32 AM CST for 32 parishes in Louisiana. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jan 3, 2009, 7:32 AM CST (13:32 UTC)
Expired: Jan 3, 2009, 9:00 AM CST
In force: 88 min
Issued by: the Storm Prediction Center

All 32 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 1Jan 3, 9:35 AM CST

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 1.5 hours before the alert went out and 136 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: 1107 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 445 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 87 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.5

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 3, 9:33 AM CST	Severe Thunderstorm Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 21 more	6 hr
Jan 3, 12:32 PM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Feliciana and 21 more	88 min
Jan 3, 4:27 PM CST	Mesoscale Discussion	SPC	Avoyelles, Caldwell, Catahoula, Concordia, Franklin, Grant and 9 more	33 min
Jan 3, 4:29 PM CST	Severe Thunderstorm Watch	SPC	Caldwell, Catahoula, Concordia, East Carroll, Franklin, Grant and 9 more	3 hr

Nearby

Mesoscale Discussions in Louisiana, 2009 Every mesoscale discussion in 2009

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.