Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 410

April 19, 202024 parishes in Louisiana; 6 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2020, 5:40 PM CDT for 24 parishes in Louisiana; 6 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 19, 2020, 5:40 PM CDT (22:40 UTC)
Expired: Apr 19, 2020, 7:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 30 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Tensas Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Franklin County, MS, Jefferson County, MS, Wilkinson County, MS

The radar

The Ft Polk radar (KPOE), 92 km from the middle of the area, began a volume at 22:40 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

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

Tornado Watch 124Apr 19, 9:35 PM CDT

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 10.7 hours before the alert went out and 166 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: 1153 J/kg
Mixed-layer CIN: -291 J/kg
Mixed-layer LCL: 1054 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 215 m²/s²
0-3 km storm-relative helicity: 276 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.7

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
Apr 18, 8:27 PM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Claiborne, De Soto, Red River and 1 more	2 hr
Apr 18, 8:56 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Cameron, East Baton Rouge and 26 more	2 hr
Apr 19, 8:41 AM CDT	Tornado Watch	SPC	Allen, Beauregard, Bienville, Bossier, Caddo, Calcasieu and 18 more	6 hr
Apr 19, 10:45 AM CDT	Mesoscale Discussion	SPC	Caldwell, De Soto, Grant, Jackson, LaSalle, Natchitoches and 5 more	2 hr
Apr 19, 11:06 AM CDT	Mesoscale Discussion	SPC	Avoyelles, Catahoula, Concordia, Franklin, Madison, Richland and 1 more	54 min
Apr 19, 11:45 AM CDT	Tornado Watch	SPC	Catahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more	9 hr
Apr 19, 12:39 PM CDT	Mesoscale Discussion	SPC	Beauregard, Calcasieu, Vernon	66 min
Apr 19, 12:47 PM CDT	Mesoscale Discussion	SPC	Avoyelles, Bienville, Caldwell, Catahoula, Concordia, De Soto and 14 more	58 min
Apr 19, 2:03 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Assumption, Avoyelles, Beauregard, Calcasieu and 23 more	57 min
Apr 19, 2:39 PM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 39 more	9 hr
Apr 19, 3:07 PM CDT	Mesoscale Discussion	SPC	Madison, Tensas	113 min
Apr 19, 6:37 PM CDT	Mesoscale Discussion	SPC	Washington	53 min
Apr 19, 2:34 AM CDT	Mesoscale Discussion	SPC	Attala, Bolivar, Calhoun, Carroll, Chickasaw, Choctaw and 29 more	116 min
Apr 19, 3:56 PM CDT	Tornado Watch	SPC	George, Greene, Perry, Stone, Wayne	6 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; radar from the NEXRAD Level II archive.