Alert archive / Texas / Mesoscale Discussions in 2014

Mesoscale Discussion 374

April 20, 2014Harmon County, Jackson County, Tillman County, Oklahoma; 17 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2014, 6:33 PM CDT for Harmon County, Jackson County, Tillman County, Oklahoma; 17 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Apr 20, 2014, 6:33 PM CDT (23:33 UTC)
Expired: Apr 20, 2014, 8:30 PM CDT
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Harmon County, OK, Jackson County, OK, Tillman County, OK, Armstrong County, TX, Briscoe County, TX, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Crosby County, TX, Dickens County, TX, Donley County, TX, Floyd County, TX, Foard County, TX, Hale County, TX, Hall County, TX, Hardeman County, TX, King County, TX, Knox County, TX, Motley County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 104 km from the middle of the area, began a volume at 23:32 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

Amarillo Airport, TX (KAMA), launched 12:00Z, 11.6 hours before the alert went out and 192 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: 974 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -16 m²/s²
0-3 km storm-relative helicity: 12 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.

Issued	Product	Office	Counties	Lasted
Apr 19, 7:00 PM CDT	Mesoscale Discussion	SPC	Brewster, Crane, Crockett, Pecos, Terrell, Upton	90 min
Apr 20, 2:55 PM CDT	Mesoscale Discussion	SPC	Briscoe, Childress, Cottle, Crosby, Dawson, Dickens and 10 more	2 hr

Nearby

Mesoscale Discussions in Texas, 2014 Mesoscale Discussions in Oklahoma, 2014 Every mesoscale discussion in 2014

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.