Alert archive / Nebraska / Mesoscale Discussions in 2007

Mesoscale Discussion 2009

September 23, 2007Logan County, Sedgwick County, Colorado; 9 counties in Nebraska; 7 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Sep 23, 2007, 1:51 PM MDT for Logan County, Sedgwick County, Colorado; 9 counties in Nebraska; 7 counties in South Dakota. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Sep 23, 2007, 1:51 PM MDT (19:51 UTC)
Expired: Sep 23, 2007, 3:45 PM MDT
In force: 114 min
Issued by: the Storm Prediction Center

Counties Logan County, CO, Sedgwick County, CO, Arthur County, NE, Cherry County, NE, Cheyenne County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Morrill County, NE, Sheridan County, NE, Bennett County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Mellette County, SD, Stanley County, SD, Todd County, SD

The radar

The North Platte radar (KLNX), 114 km from the middle of the area, began a volume at 19:50 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 685Sep 23, 2:25 PM MDT

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 7.9 hours before the alert went out and 166 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: 442 J/kg
Mixed-layer CIN: -216 J/kg
Mixed-layer LCL: 1165 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 378 m²/s²
0-3 km storm-relative helicity: 298 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

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
Sep 23, 2:23 PM MDT	Severe Thunderstorm Watch	SPC	Arthur, Blaine, Brown, Cherry, Deuel, Garden and 9 more	8 hr
Sep 23, 5:29 PM MDT	Mesoscale Discussion	SPC	Cherry, Hooker, Keya Paha, McPherson, Thomas	91 min

Nearby

Mesoscale Discussions in Nebraska, 2007 Mesoscale Discussions in South Dakota, 2007 Mesoscale Discussions in Colorado, 2007 Every mesoscale discussion in 2007

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.