Alert archive / Louisiana / Mesoscale Discussions in 2008

Mesoscale Discussion 468

March 18, 2008Ashley County, Chicot County, Union County, Arkansas; 48 parishes in Louisiana; 31 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2008, 10:34 PM CDT for Ashley County, Chicot County, Union County, Arkansas; 48 parishes in Louisiana; 31 counties in Mississippi. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Mar 18, 2008, 10:34 PM CDT (03:34 UTC)
Expired: Mar 18, 2008, 11:30 PM CDT
In force: 56 min
Issued by: the Storm Prediction Center

All 82 counties

Ashley County, AR, Chicot County, AR, Union County, AR, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberville Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, Washington Parish, LA, Webster 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, Copiah County, MS, Covington County, MS, Franklin County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Neshoba County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS

The watches that followed

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

Tornado Watch 134Mar 18, 10:50 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 3.6 hours before the alert went out and 170 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: 4 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 1138 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 301 m²/s²
0-3 km storm-relative helicity: 322 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 18, 8:43 PM CDT	Mesoscale Discussion	SPC	Clark, Cleveland, Craighead, Crittenden, Cross, Dallas and 19 more	92 min
Mar 18, 10:51 PM CDT	Tornado Watch	SPC	Ashley, Chicot	8 hr
Mar 18, 11:42 PM CDT	Mesoscale Discussion	SPC	Crittenden, St. Francis	63 min
Mar 19, 2:35 AM CDT	Mesoscale Discussion	SPC	Attala, Calhoun, Carroll, Chickasaw, Choctaw, Clay and 18 more	115 min
Mar 19, 4:55 AM CDT	Mesoscale Discussion	SPC	Attala, Calhoun, Chickasaw, Choctaw, Clay, Itawamba and 12 more	2 hr
Mar 19, 7:08 AM CDT	Mesoscale Discussion	SPC	Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 21 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2008 Mesoscale Discussions in Mississippi, 2008 Mesoscale Discussions in Arkansas, 2008 Every mesoscale discussion in 2008

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.