Alert archive / Michigan / Mesoscale Discussions in 2013

Mesoscale Discussion 730

May 20, 201319 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at May 20, 2013, 5:59 PM EDT for 19 counties in Michigan. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: May 20, 2013, 5:59 PM EDT (21:59 UTC)
Expired: May 20, 2013, 7:00 PM EDT
In force: 61 min
Issued by: the Storm Prediction Center

Counties Arenac County, MI, Bay County, MI, Genesee County, MI, Huron County, MI, Ingham County, MI, Iosco County, MI, Jackson County, MI, Lapeer County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saginaw County, MI, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Washtenaw County, MI, Wayne County, MI

The radar

The Detroit radar (KDTX), 27 km from the middle of the area, began a volume at 21:59 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

Detroit, MI (KDTX), launched 12:00Z, 10.0 hours before the alert went out and 27 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: 650 J/kg
Mixed-layer CIN: -108 J/kg
Mixed-layer LCL: 1054 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 109 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

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 20, 12:34 PM EDT	Mesoscale Discussion	SPC	Alcona, Alpena, Antrim, Arenac, Barry, Bay and 45 more	56 min
May 20, 12:58 PM EDT	Severe Thunderstorm Watch	SPC	Alcona, Allegan, Alpena, Antrim, Arenac, Barry and 55 more	7 hr

Nearby

Mesoscale Discussions in Michigan, 2013 Every mesoscale discussion in 2013

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.