Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 440

April 15, 201145 counties in Alabama; 21 parishes in Louisiana; 52 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2011, 3:35 PM CDT for 45 counties in Alabama; 21 parishes in Louisiana; 52 counties in Mississippi. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: Apr 15, 2011, 3:35 PM CDT (20:35 UTC)
Expired: Apr 15, 2011, 5:00 PM CDT
In force: 85 min
Issued by: the Storm Prediction Center

All 118 counties

Autauga County, AL, Bibb County, AL, Blount County, AL, Bullock County, AL, Butler County, AL, Chambers County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Conecuh County, AL, Coosa County, AL, Crenshaw County, AL, Cullman County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Marion County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Winston County, AL, Acadia Parish, LA, Ascension Parish, LA, Avoyelles Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Pointe Coupee Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clarke County, MS, Clay County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Hinds County, MS, Holmes County, MS, Itawamba County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Lowndes County, MS, Madison County, MS, Marion County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Warren County, MS, Wayne County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 123 km from the middle of the area, began a volume at 20:37 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 145Apr 15, 4:45 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 8.6 hours before the alert went out and 133 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: 1458 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 523 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 382 m²/s²
0-3 km storm-relative helicity: 565 m²/s²
Significant tornado parameter: 4.0
Supercell composite: 14.6

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
Apr 15, 4:21 AM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lamar, Lauderdale, Marion, Pickens	84 min
Apr 15, 7:32 AM CDT	Tornado Watch	SPC	Blount, Choctaw, Clarke, Colbert, Cullman, Fayette and 20 more	7 hr
Apr 15, 10:28 AM CDT	Mesoscale Discussion	SPC	Autauga, Baldwin, Bibb, Blount, Butler, Chilton and 34 more	2 hr
Apr 15, 11:21 AM CDT	Tornado Watch	SPC	Autauga, Baldwin, Barbour, Bibb, Blount, Bullock and 44 more	9 hr
Apr 15, 1:30 PM CDT	Mesoscale Discussion	SPC	Autauga, Bibb, Blount, Bullock, Butler, Calhoun and 46 more	2 hr
Apr 15, 5:57 PM CDT	Mesoscale Discussion	SPC	Colbert, Franklin, Lamar, Lauderdale, Lawrence, Marion	2 hr
Apr 14, 11:24 PM CDT	Severe Thunderstorm Watch	SPC	Bossier, Caddo, Claiborne, De Soto, Webster	3 hr
Apr 14, 11:56 PM CDT	Mesoscale Discussion	SPC	Bossier, Caddo, De Soto, Webster	94 min
Apr 15, 1:27 AM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Claiborne, East Carroll, Jackson, Lincoln and 5 more	93 min
Apr 15, 2:19 AM CDT	Tornado Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 20 more	8 hr
Apr 15, 2:41 PM CDT	Tornado Watch	SPC	Acadia, Ascension, Assumption, Avoyelles, Concordia, East Baton Rouge and 19 more	7 hr
Apr 15, 6:09 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 12 more	96 min
Apr 15, 12:29 PM CDT	Mesoscale Discussion	SPC	Alcorn, Benton, DeSoto, Lafayette, Marshall, Panola and 4 more	61 min
Apr 15, 2:09 PM CDT	Tornado Watch	SPC	Alcorn, Benton, Calhoun, Chickasaw, DeSoto, Itawamba and 13 more	7 hr

Nearby

Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Alabama, 2011 Mesoscale Discussions in Louisiana, 2011 Every mesoscale discussion in 2011

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.