Alert archive / Texas / Mesoscale Discussions in 2009

Mesoscale Discussion 807

May 12, 20096 counties in Oklahoma; 11 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 12, 2009, 8:16 PM CDT for 6 counties in Oklahoma; 11 counties in Texas. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: May 12, 2009, 8:16 PM CDT (01:16 UTC)
Expired: May 12, 2009, 10:15 PM CDT
In force: 119 min
Issued by: the Storm Prediction Center

Counties Beckham County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Kiowa County, OK, Tillman County, OK, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Donley County, TX, Gray County, TX, Hall County, TX, Hardeman County, TX, Hemphill County, TX, Motley County, TX, Wheeler County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 114 km from the middle of the area, began a volume at 01:17 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.

Severe Thunderstorm Watch 292May 12, 8:45 PM CDT

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 1.3 hours before the alert went out and 231 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: 1269 J/kg
Mixed-layer CIN: -335 J/kg
Mixed-layer LCL: 581 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 487 m²/s²
0-3 km storm-relative helicity: 684 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

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
May 12, 8:43 PM CDT	Severe Thunderstorm Watch	SPC	Comanche, Cotton, Greer, Harmon, Jackson, Kiowa and 1 more	3 hr
May 13, 3:21 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Beckham, Blaine, Caddo, Canadian, Cleveland and 31 more	84 min
May 13, 5:11 PM CDT	Severe Thunderstorm Watch	SPC	Alfalfa, Beckham, Blaine, Caddo, Canadian, Cleveland and 33 more	6 hr
May 13, 5:53 PM CDT	Mesoscale Discussion	SPC	Jefferson	67 min
May 13, 6:30 PM CDT	Mesoscale Discussion	SPC	Blaine, Caddo, Canadian, Custer, Garfield, Kay and 9 more	90 min

Nearby

Mesoscale Discussions in Texas, 2009 Mesoscale Discussions in Oklahoma, 2009 Every mesoscale discussion in 2009

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.