Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 2516

November 18, 200331 parishes in Louisiana; 15 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Nov 18, 2003, 2:08 AM CST for 31 parishes in Louisiana; 15 counties in Mississippi. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Nov 18, 2003, 2:08 AM CST (08:08 UTC)
Expired: Nov 18, 2003, 3:45 AM CST
In force: 97 min
Issued by: the Storm Prediction Center

All 46 counties

Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Franklin Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Pointe Coupee Parish, LA, Richland Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Issaquena County, MS, Jefferson County, MS, Lawrence County, MS, Lincoln County, MS, Pike County, MS, Walthall County, MS, Warren County, MS, Wilkinson County, MS, Yazoo County, MS

The watches that followed

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

Tornado Watch 957Nov 18, 2:25 AM CST

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 8.1 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: 877 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 631 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 200 m²/s²
0-3 km storm-relative helicity: 222 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 7.0

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.

Issued	Product	Office	Counties	Lasted
Nov 17, 7:48 PM CST	Mesoscale Discussion	SPC	Bossier, Caddo, Claiborne, Webster	87 min
Nov 17, 8:10 PM CST	Mesoscale Discussion	SPC	Beauregard, Calcasieu, Natchitoches, Sabine, Vernon	95 min
Nov 17, 9:25 PM CST	Tornado Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 12 more	7 hr
Nov 17, 10:53 PM CST	Mesoscale Discussion	SPC	Beauregard, Calcasieu	97 min
Nov 17, 11:44 PM CST	Mesoscale Discussion	SPC	Bienville, Bossier, Caldwell, Claiborne, De Soto, Grant and 11 more	91 min
Nov 17, 11:50 PM CST	Tornado Watch	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 2 more	5 hr
Nov 18, 2:25 AM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	6 hr
Nov 18, 4:48 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana, Iberville and 17 more	117 min
Nov 18, 6:08 AM CST	Mesoscale Discussion	SPC	Ascension, Jefferson, Lafourche, Livingston, Orleans, Plaquemines and 8 more	2 hr
Nov 18, 6:55 AM CST	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, Jefferson, Lafourche, Livingston and 11 more	5 hr
Nov 18, 10:30 AM CST	Mesoscale Discussion	SPC	Saint Bernard	90 min
Nov 18, 1:29 AM CST	Mesoscale Discussion	SPC	Bolivar, Coahoma, DeSoto, Leflore, Marshall, Panola and 5 more	3 hr
Nov 18, 1:55 AM CST	Tornado Watch	SPC	Bolivar, Coahoma, DeSoto, Holmes, Humphreys, Leflore and 7 more	6 hr
Nov 18, 11:25 AM CST	Tornado Watch	SPC	George, Greene, Jackson	6 hr
Nov 18, 2:50 PM CST	Severe Thunderstorm Watch	SPC	Bolivar, Washington	5 hr

Nearby

Mesoscale Discussions in Louisiana, 2003 Mesoscale Discussions in Mississippi, 2003 Every mesoscale discussion in 2003

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.