Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 2123

October 22, 200925 parishes in Louisiana; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Oct 22, 2009, 7:48 AM CDT for 25 parishes in Louisiana; 15 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Oct 22, 2009, 7:48 AM CDT (12:48 UTC)
Expired: Oct 22, 2009, 9:45 AM CDT
In force: 117 min
Issued by: the Storm Prediction Center

All 40 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Chambers County, TX, Galveston County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 73 km from the middle of the area, began a volume at 12:49 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 0.8 hours before the alert went out and 75 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: 833 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 773 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 182 m²/s²
0-3 km storm-relative helicity: 223 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 5.9

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
Oct 22, 5:35 AM CDT	Mesoscale Discussion	SPC	Beauregard, Calcasieu, De Soto, Sabine, Vernon	85 min
Oct 22, 5:55 AM CDT	Tornado Watch	SPC	Acadia, Allen, Beauregard, Calcasieu, Caldwell, Cameron and 12 more	6 hr
Oct 22, 10:14 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 10 more	91 min
Oct 22, 11:27 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Avoyelles, Caldwell, Catahoula, Concordia and 26 more	93 min
Oct 22, 11:58 AM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 40 more	7 hr
Oct 22, 3:36 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Carroll and 14 more	114 min
Oct 22, 4:35 PM CDT	Tornado Watch	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 5 more	4 hr
Oct 22, 6:26 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Carroll, East Feliciana, Livingston and 5 more	34 min
Oct 21, 7:11 PM CDT	Mesoscale Discussion	SPC	Bell, Blanco, Bosque, Burnet, Comal, Coryell and 12 more	94 min

Nearby

Mesoscale Discussions in Louisiana, 2009 Mesoscale Discussions in Texas, 2009 Every mesoscale discussion in 2009

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.