Alert archive / Texas / Mesoscale Discussions in 2003

Mesoscale Discussion 108

February 21, 200310 parishes in Louisiana; 24 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Feb 21, 2003, 11:47 AM CST for 10 parishes in Louisiana; 24 counties in Texas. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued
Feb 21, 2003, 11:47 AM CST (17:47 UTC)
Expired
Feb 21, 2003, 1:45 PM CST
In force
118 min
Issued by
the Storm Prediction Center
All 34 counties

Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Angelina County, TX, Brazoria County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX, Waller County, TX, Wharton County, TX

The radar

The Lake Charles radar (KLCH), 101 km from the middle of the area, began a volume at 17:49 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 watches that followed

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

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 5.8 hours before the alert went out and 103 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-pSkew-T log-p diagram, Lake Charles Mun, LA at 12:00Z on 2003-02-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 543 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lake Charles Mun, LA at 12:00Z on 2003-02-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 253 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
543 J/kg
Mixed-layer CIN
-114 J/kg
Mixed-layer LCL
433 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
253 m²/s²
0-3 km storm-relative helicity
274 m²/s²
Significant tornado parameter
0.0
Supercell composite
6.2

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.

IssuedProductOfficeCountiesLasted
Feb 21, 1:43 AM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 6 more2 hr
Feb 21, 4:35 AM CSTMesoscale DiscussionSPCAscension, Assumption, Avoyelles, Concordia, East Baton Rouge, East Feliciana and 16 more115 min
Feb 21, 9:02 AM CSTMesoscale DiscussionSPCBeauregard, Calcasieu, Cameron, Sabine, Vernon58 min
Feb 21, 9:40 AM CSTTornado WatchSPCAcadia, Allen, Beauregard, Calcasieu, Caldwell, Cameron and 11 more6 hr
Feb 21, 3:32 PM CSTMesoscale DiscussionSPCAllen, Beauregard, Calcasieu, Evangeline, Jefferson Davis, Vernon118 min
Feb 21, 3:40 PM CSTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more6 hr
Feb 21, 5:20 PM CSTMesoscale DiscussionSPCClaiborne, East Carroll, Franklin, Jackson, Lincoln, Madison and 5 more4 hr
Feb 21, 5:50 PM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more115 min
Feb 21, 2:43 AM CSTMesoscale DiscussionSPCDimmit, Edwards, Frio, Kinney, La Salle, Maverick and 5 more3 hr
Feb 21, 3:53 AM CSTMesoscale DiscussionSPCAransas, Austin, Brazoria, Calhoun, Colorado, Fort Bend and 13 more3 hr
Feb 21, 4:10 AM CSTSevere Thunderstorm WatchSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Brazos and 26 more6 hr
Feb 21, 4:25 AM CSTTornado WatchSPCAustin, Brazoria, Brazos, Burleson, Calhoun, Colorado and 15 more6 hr
Feb 21, 5:58 AM CSTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Brazos and 26 more2 hr
Feb 21, 6:16 AM CSTMesoscale DiscussionSPCAustin, Brazoria, Brazos, Burleson, Calhoun, Colorado and 17 more119 min
Feb 21, 1:30 PM CSTMesoscale DiscussionSPCHardin, Harris, Jasper, Liberty, Montgomery, Newton and 3 more2 hr

Nearby

Mesoscale Discussions in Texas, 2003Mesoscale Discussions in Louisiana, 2003Every mesoscale discussion in 2003

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.