Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 1111

June 21, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2017, 3:42 PM CDT for 4 states. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Jun 21, 2017, 3:42 PM CDT (20:42 UTC)
Expired: Jun 21, 2017, 5:15 PM CDT
In force: 93 min
Issued by: the Storm Prediction Center

Counties Baldwin County, AL, Mobile County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, Assumption Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Jackson County, MS

The watches that followed

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

Tornado Watch 362Jun 21, 6:45 PM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 8.7 hours before the alert went out and 34 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: 262 J/kg
Mixed-layer CIN: -75 J/kg
Mixed-layer LCL: 465 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 485 m²/s²
0-3 km storm-relative helicity: 506 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.3

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
Jun 20, 8:15 PM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	3 hr
Jun 20, 9:48 PM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	57 min
Jun 20, 10:24 PM CDT	Tornado Watch	SPC	Baldwin, Mobile	12 hr
Jun 21, 2:08 AM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	2 hr
Jun 21, 7:47 AM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	118 min
Jun 21, 10:01 AM CDT	Tornado Watch	SPC	Baldwin, Covington, Escambia, Mobile	9 hr
Jun 21, 6:29 PM CDT	Mesoscale Discussion	SPC	Baldwin, Conecuh, Covington, Escambia, Mobile, Washington	61 min
Jun 21, 6:45 PM CDT	Tornado Watch	SPC	Baldwin, Butler, Clarke, Conecuh, Covington, Crenshaw and 5 more	8 hr

Nearby

Mesoscale Discussions in Louisiana, 2017 Mesoscale Discussions in Florida, 2017 Mesoscale Discussions in Alabama, 2017 Every mesoscale discussion in 2017

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.