Alert archive / Nebraska / Mesoscale Discussions in 2017

Mesoscale Discussion 1647

September 15, 201727 counties in Nebraska; 6 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Sep 15, 2017, 5:48 PM CDT for 27 counties in Nebraska; 6 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 15, 2017, 5:48 PM CDT (22:48 UTC)
Expired: Sep 15, 2017, 8:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 33 counties

Antelope County, NE, Boone County, NE, Buffalo County, NE, Butler County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Knox County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Phelps County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Sherman County, NE, Stanton County, NE, Valley County, NE, Wayne County, NE, Wheeler County, NE, York County, NE, Clay County, SD, Lincoln County, SD, Minnehaha County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Omaha radar (KOAX), 145 km from the middle of the area, began a volume at 22:51 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 10.8 hours before the alert went out and 289 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: 124 J/kg
Mixed-layer CIN: -561 J/kg
Mixed-layer LCL: 1508 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 217 m²/s²
0-3 km storm-relative helicity: 256 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>

Nearby

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