Alert archive / Montana / Mesoscale Discussions in 2013

Mesoscale Discussion 1797

August 29, 20137 counties in Idaho; 15 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Aug 29, 2013, 1:34 PM PDT for 7 counties in Idaho; 15 counties in Montana. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Aug 29, 2013, 1:34 PM PDT (20:34 UTC)
Expired: Aug 29, 2013, 2:30 PM PDT
In force: 56 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 22 counties

Benewah County, ID, Bonner County, ID, Boundary County, ID, Clearwater County, ID, Idaho County, ID, Kootenai County, ID, Shoshone County, ID, Cascade County, MT, Flathead County, MT, Glacier County, MT, Granite County, MT, Lake County, MT, Lewis and Clark County, MT, Lincoln County, MT, Mineral County, MT, Missoula County, MT, Pondera County, MT, Powell County, MT, Ravalli County, MT, Sanders County, MT, Teton County, MT, Toole County, MT

The radar

The Missoula radar (KMSX), 25 km from the middle of the area, began a volume at 20:35 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

Spokane, WA (KOTX), launched 12:00Z, 8.6 hours before the alert went out and 175 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: 2282 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 203 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 29, 3:13 PM PDT	Mesoscale Discussion	SPC	Bannock, Bear Lake, Caribou, Franklin, Oneida	92 min
Aug 28, 6:55 PM PDT	Mesoscale Discussion	SPC	Custer, Dawson, Fallon, McCone, Prairie, Richland and 3 more	95 min

Nearby

Mesoscale Discussions in Montana, 2013 Mesoscale Discussions in Idaho, 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.