Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 157

March 4, 202023 parishes in Louisiana; 5 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 4, 2020, 1:57 PM CST for 23 parishes in Louisiana; 5 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 4, 2020, 1:57 PM CST (19:57 UTC)
Expired: Mar 4, 2020, 4:00 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 28 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans 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 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, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Stone County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 8.0 hours before the alert went out and 83 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: 1479 J/kg
Mixed-layer CIN: -69 J/kg
Mixed-layer LCL: 585 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 156 m²/s²
0-3 km storm-relative helicity: 351 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 7.9

Open this sounding in Storm Lab

The text

As transmitted.

<!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 4, 1:19 AM CST	Mesoscale Discussion	SPC	Avoyelles, Bienville, Bossier, Caddo, Caldwell, Catahoula and 24 more	2 hr
Mar 4, 1:53 AM CST	Tornado Watch	SPC	Catahoula, Concordia, East Carroll, East Feliciana, Franklin, Madison and 9 more	8 hr
Mar 4, 4:20 AM CST	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, De Soto, Grant and 11 more	115 min
Mar 4, 5:02 AM CST	Severe Thunderstorm Watch	SPC	Allen, Avoyelles, Beauregard, Bienville, Caldwell, De Soto and 12 more	7 hr
Mar 4, 10:50 AM CST	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 24 more	115 min
Mar 4, 5:05 PM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 13 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2020 Mesoscale Discussions in Mississippi, 2020 Every mesoscale discussion in 2020

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.