Alert archive / Wyoming / Mesoscale Discussions in 2018

Mesoscale Discussion 941

June 29, 2018Big Horn County, Carbon County, Montana; 5 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 29, 2018, 11:23 AM MDT for Big Horn County, Carbon County, Montana; 5 counties in Wyoming. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jun 29, 2018, 11:23 AM MDT (17:23 UTC)
Expired: Jun 29, 2018, 1:00 PM MDT
In force: 97 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Big Horn County, MT, Carbon County, MT, Big Horn County, WY, Fremont County, WY, Hot Springs County, WY, Sheridan County, WY, Washakie County, WY

The radar

The Riverton/Lander radar (KRIW), 144 km from the middle of the area, began a volume at 17:23 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

Riverton, WY (KRIW), launched 12:00Z, 5.4 hours before the alert went out and 144 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: 256 J/kg
Mixed-layer CIN: -222 J/kg
Mixed-layer LCL: 1500 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.3

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>

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 28, 8:06 PM MDT	Mesoscale Discussion	SPC	Carter, Custer, Dawson, Fallon, Garfield, McCone and 7 more	84 min
Jun 29, 1:06 PM MDT	Severe Thunderstorm Watch	SPC	Carter, Powder River	9 hr
Jun 29, 2:29 PM MDT	Mesoscale Discussion	SPC	Carter, Powder River	91 min
Jun 29, 12:30 PM MDT	Mesoscale Discussion	SPC	Big Horn, Campbell, Converse, Crook, Johnson, Natrona and 4 more	60 min
Jun 29, 4:31 PM MDT	Mesoscale Discussion	SPC	Goshen, Laramie, Platte	89 min
Jun 29, 5:19 PM MDT	Severe Thunderstorm Watch	SPC	Goshen, Laramie, Platte	8 hr

Nearby

Mesoscale Discussions in Wyoming, 2018 Mesoscale Discussions in Montana, 2018 Every mesoscale discussion in 2018

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.