Alert archive / Texas / Mesoscale Discussions in 2013

Mesoscale Discussion 747

May 21, 201314 counties in Oklahoma; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 21, 2013, 8:12 AM CDT for 14 counties in Oklahoma; 15 counties in Texas. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued
May 21, 2013, 8:12 AM CDT (13:12 UTC)
Expired
May 21, 2013, 9:45 AM CDT
In force
93 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 29 counties

Atoka County, OK, Bryan County, OK, Carter County, OK, Choctaw County, OK, Coal County, OK, Jefferson County, OK, Johnston County, OK, Latimer County, OK, LeFlore County, OK, Love County, OK, Marshall County, OK, McCurtain County, OK, Pittsburg County, OK, Pushmataha County, OK, Archer County, TX, Clay County, TX, Collin County, TX, Cooke County, TX, Delta County, TX, Denton County, TX, Fannin County, TX, Grayson County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Lamar County, TX, Montague County, TX, Red River County, TX, Wise County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 143 km from the middle of the area, began a volume at 13:14 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

Fort Worth, TX (KFWD), launched 12:00Z, 1.2 hours before the alert went out and 116 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, Fort Worth, TX at 12:00Z on 2013-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1513 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, Fort Worth, TX at 12:00Z on 2013-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 316 square meters per square second.193958Sfc1 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
1513 J/kg
Mixed-layer CIN
-271 J/kg
Mixed-layer LCL
793 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
316 m²/s²
0-3 km storm-relative helicity
251 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

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.

IssuedProductOfficeCountiesLasted
May 20, 7:39 PM CDTTornado WatchSPCAdair, Atoka, Bryan, Carter, Choctaw, Haskell and 10 more6 hr
May 20, 11:36 PM CDTMesoscale DiscussionSPCAtoka, Coal, Garvin, Hughes, Murray, Pittsburg and 2 more24 min
May 21, 12:03 AM CDTSevere Thunderstorm WatchSPCAtoka, Caddo, Carter, Cleveland, Coal, Comanche and 19 more7 hr
May 21, 4:20 AM CDTMesoscale DiscussionSPCAtoka, Carter, Cleveland, Coal, Comanche, Garvin and 17 more55 min
May 21, 9:46 AM CDTMesoscale DiscussionSPCCaddo, Canadian, Cleveland, Comanche, Cotton, Creek and 26 more2 hr
May 21, 10:26 AM CDTTornado WatchSPCBryan, Choctaw, Love, Marshall10 hr
May 21, 10:45 AM CDTSevere Thunderstorm WatchSPCAtoka, Caddo, Canadian, Carter, Cleveland, Coal and 30 more6 hr
May 21, 1:19 PM CDTMesoscale DiscussionSPCBryan, Choctaw, Marshall, Pushmataha116 min
May 21, 1:50 PM CDTTornado WatchSPCMcCurtain8 hr
May 21, 3:18 PM CDTMesoscale DiscussionSPCBryan, Choctaw, McCurtain, Pushmataha87 min
May 20, 8:45 PM CDTMesoscale DiscussionSPCBosque, Brown, Burnet, Callahan, Clay, Coleman and 37 more60 min
May 21, 10:09 AM CDTMesoscale DiscussionSPCAnderson, Bosque, Bowie, Brown, Callahan, Camp and 57 more96 min
May 21, 1:35 PM CDTMesoscale DiscussionSPCAnderson, Bowie, Camp, Cass, Cherokee, Delta and 17 more115 min
May 21, 4:55 PM CDTMesoscale DiscussionSPCBrazos, Burleson, Houston, Madison, Trinity, Walker95 min
May 21, 5:54 PM CDTMesoscale DiscussionSPCAnderson, Bowie, Camp, Cass, Cherokee, Gregg and 11 more66 min
May 21, 6:55 PM CDTSevere Thunderstorm WatchSPCBrazos, Burleson, Grimes, Hardin, Houston, Jasper and 9 more6 hr

Nearby

Mesoscale Discussions in Texas, 2013Mesoscale Discussions in Oklahoma, 2013Every mesoscale discussion in 2013

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.