Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 532

April 21, 20175 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2017, 1:07 AM CDT for 5 counties in Texas. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: Apr 21, 2017, 1:07 AM CDT (06:07 UTC)
Expired: Apr 21, 2017, 3:00 AM CDT
In force: 113 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Cooke County, TX, Denton County, TX, Grayson County, TX, Montague County, TX, Wise County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 105 km from the middle of the area, began a volume at 06:10 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

Norman, OK (KOUN), launched 00:00Z, 6.1 hours before the alert went out and 193 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 909 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 121 m²/s²
0-3 km storm-relative helicity: 350 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.6

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 20, 9:33 PM CDT	Severe Thunderstorm Watch	SPC	Archer, Baylor, Briscoe, Childress, Clay, Collingsworth and 12 more	7 hr
Apr 20, 11:30 PM CDT	Mesoscale Discussion	SPC	Armstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 11 more	60 min
Apr 21, 3:44 AM CDT	Mesoscale Discussion	SPC	Armstrong, Carson, Collingsworth, Donley, Gray, Hansford and 8 more	2 hr
Apr 21, 4:20 AM CDT	Severe Thunderstorm Watch	SPC	Armstrong, Carson, Collingsworth, Dallam, Donley, Gray and 13 more	8 hr
Apr 21, 3:09 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Bowie, Camp, Cass, Clay and 33 more	2 hr
Apr 21, 4:40 PM CDT	Tornado Watch	SPC	Bosque, Bowie, Camp, Cass, Collin, Comanche and 40 more	8 hr

Nearby

Mesoscale Discussions in Texas, 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.