Alert archive / North Dakota / Mesoscale Discussions in 2011

Mesoscale Discussion 1987

August 15, 2011Fallon County, Montana; 13 counties in North Dakota; 4 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2011, 2:47 PM MDT for Fallon County, Montana; 13 counties in North Dakota; 4 counties in South Dakota. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued: Aug 15, 2011, 2:47 PM MDT (20:47 UTC)
Expired: Aug 15, 2011, 3:45 PM MDT
In force: 58 min
Issued by: the Storm Prediction Center

Counties Fallon County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Grant County, ND, Hettinger County, ND, McLean County, ND, Mercer County, ND, Morton County, ND, Oliver County, ND, Sioux County, ND, Slope County, ND, Stark County, ND, Butte County, SD, Harding County, SD, Lawrence County, SD, Perkins County, SD

The radar

The Bismarck radar (KBIS), 180 km from the middle of the area, began a volume at 20:48 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 782Aug 15, 4:25 PM MDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 8.8 hours before the alert went out and 184 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: 7951 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: 119 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
Aug 15, 1:38 PM MDT	Mesoscale Discussion	SPC	Beaverhead, Broadwater, Carbon, Deer Lodge, Gallatin, Jefferson and 7 more	2 hr
Aug 15, 4:23 PM MDT	Severe Thunderstorm Watch	SPC	Carter, Custer, Dawson, Fallon, McCone, Powder River and 3 more	9 hr
Aug 14, 7:42 PM MDT	Mesoscale Discussion	SPC	Emmons, Grant, Logan, McIntosh, Morton, Sioux	93 min
Aug 15, 2:22 AM MDT	Mesoscale Discussion	SPC	Burleigh, McLean, Mercer, Morton, Oliver	2 hr

Nearby

Mesoscale Discussions in North Dakota, 2011 Mesoscale Discussions in South Dakota, 2011 Mesoscale Discussions in Montana, 2011 Every mesoscale discussion in 2011

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.