Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 617

May 16, 2020Ashley County, Chicot County, Drew County, Arkansas; 5 parishes in Louisiana; 5 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 16, 2020, 6:21 PM CDT for Ashley County, Chicot County, Drew County, Arkansas; 5 parishes in Louisiana; 5 counties in Mississippi. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: May 16, 2020, 6:21 PM CDT (23:21 UTC)
Expired: May 16, 2020, 7:45 PM CDT
In force: 84 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

Counties Ashley County, AR, Chicot County, AR, Drew County, AR, East Carroll Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Richland Parish, LA, West Carroll Parish, LA, Humphreys County, MS, Issaquena County, MS, Sharkey County, MS, Warren County, MS, Washington County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 147 km from the middle of the area, began a volume at 23:23 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 nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 11.4 hours before the alert went out and 226 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: 144 J/kg
Mixed-layer CIN: -88 J/kg
Mixed-layer LCL: 699 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
May 16, 1:16 PM CDT	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Clark, Cleveland, Columbia and 19 more	2 hr
May 16, 3:27 PM CDT	Tornado Watch	SPC	Calhoun, Clark, Columbia, Dallas, Garland, Hempstead and 12 more	6 hr
May 16, 5:31 PM CDT	Mesoscale Discussion	SPC	Columbia, Hempstead, Howard, Lafayette, Little River, Miller and 4 more	59 min

Nearby

Mesoscale Discussions in Louisiana, 2020 Mesoscale Discussions in Mississippi, 2020 Mesoscale Discussions in Arkansas, 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.