Alert archive / Texas / Mesoscale Discussions in 2003

Mesoscale Discussion 273

March 18, 20034 states

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2003, 9:36 AM CST for 4 states. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2003, 9:36 AM CST (15:36 UTC)
Expired
Mar 18, 2003, 12:30 PM CST
In force
3 hr
Issued by
the Storm Prediction Center
All 42 counties

Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Pike County, AR, Sevier County, AR, Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Red River Parish, LA, Sabine Parish, LA, Webster Parish, LA, McCurtain County, OK, Angelina County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Franklin County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Jasper County, TX, Liberty County, TX, Marion County, TX, Montgomery County, TX, Morris County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Polk County, TX, Red River County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Titus County, TX, Trinity County, TX, Tyler County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 88 km from the middle of the area, began a volume at 15:38 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

Shreveport, LA (KSHV), launched 12:00Z, 3.6 hours before the alert went out and 97 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, Shreveport, LA at 12:00Z on 2003-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 29 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, Shreveport, LA at 12:00Z on 2003-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 99 square meters per square second.1939587897117Sfc1 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
29 J/kg
Mixed-layer CIN
-184 J/kg
Mixed-layer LCL
707 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
99 m²/s²
0-3 km storm-relative helicity
132 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.

IssuedProductOfficeCountiesLasted
Mar 18, 2:15 PM CSTTornado WatchSPCAshley, Chicot, Union7 hr
Mar 18, 11:40 AM CSTTornado WatchSPCAllen, Beauregard, Calcasieu, Cameron, Grant, Natchitoches and 2 more5 hr
Mar 18, 1:12 PM CSTMesoscale DiscussionSPCBienville, Caldwell, Catahoula, De Soto, Franklin, Grant and 13 more2 hr
Mar 18, 3:33 PM CSTMesoscale DiscussionSPCBienville, Caldwell, Catahoula, De Soto, Franklin, Grant and 13 more57 min
Mar 18, 4:30 PM CSTMesoscale DiscussionSPCAscension, East Baton Rouge, East Carroll, East Feliciana, Livingston, Madison and 8 more2 hr
Mar 18, 5:05 PM CSTTornado WatchSPCAscension, East Baton Rouge, East Feliciana, Iberville, Livingston, Saint Helena and 4 more6 hr
Mar 17, 6:50 PM CSTSevere Thunderstorm WatchSPCAlfalfa, Blaine, Custer, Dewey, Garfield, Grant and 10 more4 hr
Mar 17, 8:19 PM CSTMesoscale DiscussionSPCCaddo, Carter, Cleveland, Comanche, Cotton, Garvin and 9 more86 min
Mar 17, 9:04 PM CSTMesoscale DiscussionSPCAlfalfa, Garfield, Grant, Kay, Kingfisher, Logan and 4 more86 min
Mar 17, 10:27 PM CSTMesoscale DiscussionSPCArcher, Brown, Callahan, Coleman, Comanche, Concho and 20 more3 hr
Mar 18, 2:03 AM CSTMesoscale DiscussionSPCBell, Bosque, Burnet, Collin, Coryell, Dallas and 23 more3 hr

Nearby

Mesoscale Discussions in Texas, 2003Mesoscale Discussions in Arkansas, 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.