Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 347

March 31, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2009, 11:54 AM CDT for 4 states. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Mar 31, 2009, 11:54 AM CDT (16:54 UTC)
Expired: Mar 31, 2009, 1:30 PM CDT
In force: 96 min
Issued by: the Storm Prediction Center

All 98 counties

Sumter County, AL, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, LaSalle Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Richland Parish, LA, Saint Bernard 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, Tensas Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hancock County, MS, Harrison County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Warren County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS, Newton County, TX, Orange County, TX

The watches that followed

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

Severe Thunderstorm Watch 98Mar 31, 1:00 PM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 4.9 hours before the alert went out and 134 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: 377 J/kg
Mixed-layer CIN: -94 J/kg
Mixed-layer LCL: 522 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 287 m²/s²
0-3 km storm-relative helicity: 408 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.2

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
Mar 31, 11:32 AM CDT	Mesoscale Discussion	SPC	Baldwin, Covington, Escambia, Mobile, Washington	88 min
Mar 31, 1:05 PM CDT	Severe Thunderstorm Watch	SPC	Baldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 11 more	8 hr
Mar 31, 3:15 PM CDT	Mesoscale Discussion	SPC	Coffee, Covington, Dale, Escambia, Geneva, Henry and 1 more	90 min
Mar 31, 5:12 PM CDT	Mesoscale Discussion	SPC	Baldwin, Clarke, Coffee, Conecuh, Covington, Dale and 7 more	93 min
Mar 31, 8:58 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Avoyelles, Catahoula, Concordia and 19 more	92 min
Mar 31, 9:37 AM CDT	Severe Thunderstorm Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 38 more	7 hr
Mar 31, 2:44 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 37 more	91 min
Mar 30, 7:40 PM CDT	Mesoscale Discussion	SPC	Clay, Cooke, Grayson	2 hr
Mar 30, 8:31 PM CDT	Mesoscale Discussion	SPC	Collin, Cooke, Dallas, Delta, Denton, Fannin and 11 more	89 min
Mar 30, 8:49 PM CDT	Severe Thunderstorm Watch	SPC	Collin, Cooke, Dallas, Delta, Denton, Ellis and 16 more	5 hr
Mar 30, 10:27 PM CDT	Mesoscale Discussion	SPC	Camp, Collin, Cooke, Dallas, Delta, Denton and 23 more	93 min
Mar 30, 11:42 PM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Collin, Dallas, Delta and 21 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2009 Mesoscale Discussions in Mississippi, 2009 Mesoscale Discussions in Texas, 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.