Alert archive / Montana / Mesoscale Discussions in 2011

Mesoscale Discussion 1688

July 22, 201117 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jul 22, 2011, 1:06 PM MDT for 17 counties in Montana. It was in force for 24 min.

The area

The outline as issued.

The facts

Issued: Jul 22, 2011, 1:06 PM MDT (19:06 UTC)
Expired: Jul 22, 2011, 1:30 PM MDT
In force: 24 min
Issued by: the Storm Prediction Center

Counties Big Horn County, MT, Custer County, MT, Daniels County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Phillips County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Rosebud County, MT, Treasure County, MT, Valley County, MT, Wibaux County, MT, Yellowstone County, MT

The radar

The Glasgow radar (KGGW), 137 km from the middle of the area, began a volume at 19:07 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.

Tornado Watch 671Jul 22, 1:25 PM MDT

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 7.1 hours before the alert went out and 138 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: 2097 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 99 m²/s²
0-3 km storm-relative helicity: 114 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
Jul 22, 10:05 AM MDT	Mesoscale Discussion	SPC	Custer, Dawson, Fallon, McCone, Prairie, Richland and 2 more	55 min
Jul 22, 1:25 PM MDT	Tornado Watch	SPC	Carter, Custer, Daniels, Dawson, Fallon, Garfield and 11 more	8 hr
Jul 22, 4:17 PM MDT	Mesoscale Discussion	SPC	Big Horn, Carbon, Carter, Custer, Dawson, Fallon and 13 more	88 min

Nearby

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.