Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 594

April 29, 2017Bryan County, Marshall County, Oklahoma; 12 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2017, 2:10 PM CDT for Bryan County, Marshall County, Oklahoma; 12 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 29, 2017, 2:10 PM CDT (19:10 UTC)
Expired: Apr 29, 2017, 4:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Bryan County, OK, Marshall County, OK, Collin County, TX, Dallas County, TX, Denton County, TX, Ellis County, TX, Fannin County, TX, Grayson County, TX, Hill County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Rockwall County, TX, Tarrant County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 67 km from the middle of the area, began a volume at 19:13 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 175Apr 29, 5:10 PM CDT

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 7.2 hours before the alert went out and 50 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: 2666 J/kg
Mixed-layer CIN: -137 J/kg
Mixed-layer LCL: 683 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 353 m²/s²
0-3 km storm-relative helicity: 528 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 14.1

Open this sounding in Storm Lab

The text

As transmitted.

<!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 28, 10:01 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Cherokee, Craig, Creek, Delaware, Haskell and 17 more	9 hr
Apr 28, 10:18 PM CDT	Mesoscale Discussion	SPC	Beckham, Blaine, Caddo, Canadian, Cleveland, Comanche and 18 more	117 min
Apr 28, 10:35 PM CDT	Severe Thunderstorm Watch	SPC	Beckham, Blaine, Caddo, Canadian, Cleveland, Comanche and 21 more	8 hr
Apr 29, 2:45 AM CDT	Mesoscale Discussion	SPC	Beckham, Blaine, Caddo, Canadian, Cleveland, Comanche and 21 more	2 hr
Apr 29, 3:39 AM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Craig, Creek, Delaware, Mayes and 7 more	96 min
Apr 29, 4:04 AM CDT	Mesoscale Discussion	SPC	Cimarron	6 hr
Apr 29, 1:11 PM CDT	Mesoscale Discussion	SPC	Adair, Haskell, Latimer, LeFlore, McCurtain, Pushmataha and 1 more	2 hr
Apr 29, 5:36 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Choctaw, Haskell, Latimer, LeFlore, Pushmataha and 1 more	4 hr
Apr 29, 9:19 AM CDT	Mesoscale Discussion	SPC	Hardin, Jasper, Newton, Orange, Sabine, Tyler	116 min
Apr 29, 5:10 PM CDT	Tornado Watch	SPC	Anderson, Camp, Cherokee, Delta, Fannin, Franklin and 18 more	5 hr
Apr 29, 6:31 PM CDT	Mesoscale Discussion	SPC	Bastrop, Caldwell, Falls, Lee, Milam, Travis and 1 more	59 min
Apr 29, 6:50 PM CDT	Severe Thunderstorm Watch	SPC	Austin, Bastrop, Bell, Brazos, Burleson, Caldwell and 20 more	4 hr

Nearby

Mesoscale Discussions in Texas, 2017 Mesoscale Discussions in Oklahoma, 2017 Every mesoscale discussion in 2017

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.