Alert archive / South Dakota / Mesoscale Discussions in 2017

Mesoscale Discussion 1568

August 25, 20179 counties in Nebraska; 26 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 25, 2017, 5:58 PM CDT for 9 counties in Nebraska; 26 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 25, 2017, 5:58 PM CDT (22:58 UTC)
Expired: Aug 25, 2017, 8:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 35 counties

Antelope County, NE, Boyd County, NE, Brown County, NE, Cedar County, NE, Holt County, NE, Keya Paha County, NE, Knox County, NE, Pierce County, NE, Rock County, NE, Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Clark County, SD, Davison County, SD, Douglas County, SD, Faulk County, SD, Gregory County, SD, Hand County, SD, Hanson County, SD, Hutchinson County, SD, Hyde County, SD, Jerauld County, SD, Kingsbury County, SD, Lake County, SD, Lyman County, SD, McCook County, SD, Miner County, SD, Sanborn County, SD, Spink County, SD, Tripp County, SD, Turner County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 119 km from the middle of the area, began a volume at 23:00 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

Aberdeen, SD (KABR), launched 12:00Z, 11.0 hours before the alert went out and 149 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: 742 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 36 m²/s²
0-3 km storm-relative helicity: 134 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Aug 25, 2:57 PM CDT	Mesoscale Discussion	SPC	Antelope, Boyd, Cedar, Holt, Keya Paha, Knox and 1 more	3 hr
Aug 25, 3:38 PM CDT	Severe Thunderstorm Watch	SPC	Antelope, Boyd, Brown, Cedar, Holt, Keya Paha and 3 more	7 hr
Aug 25, 3:46 PM CDT	Mesoscale Discussion	SPC	Butte, Custer, Lawrence, Oglala Lakota	89 min

Nearby

Mesoscale Discussions in South Dakota, 2017 Mesoscale Discussions in Nebraska, 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.