Alert archive / Missouri / Mesoscale Discussions in 2012

Mesoscale Discussion 1977

September 21, 201214 counties in Arkansas; 16 counties in Missouri; Delaware County, Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Sep 21, 2012, 12:45 AM CDT for 14 counties in Arkansas; 16 counties in Missouri; Delaware County, Oklahoma. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 21, 2012, 12:45 AM CDT (05:45 UTC)
Expired
Sep 21, 2012, 2:45 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 31 counties

Baxter County, AR, Benton County, AR, Boone County, AR, Carroll County, AR, Fulton County, AR, Izard County, AR, Madison County, AR, Marion County, AR, Newton County, AR, Randolph County, AR, Searcy County, AR, Sharp County, AR, Stone County, AR, Washington County, AR, Barry County, MO, Carter County, MO, Christian County, MO, Douglas County, MO, Howell County, MO, Lawrence County, MO, McDonald County, MO, Newton County, MO, Oregon County, MO, Ozark County, MO, Ripley County, MO, Shannon County, MO, Stone County, MO, Taney County, MO, Webster County, MO, Wright County, MO, Delaware County, OK

The radar

The Springfield radar (KSGF), 102 km from the middle of the area, began a volume at 05:46 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

Springfield, MO (KSGF), launched 00:00Z, 5.8 hours before the alert went out and 104 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-pSkew-T log-p diagram, Springfield, MO at 00:00Z on 2012-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Springfield, MO at 00:00Z on 2012-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2363 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
134 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.

IssuedProductOfficeCountiesLasted
Sep 21, 4:59 PM CDTMesoscale DiscussionSPCCity of Saint Louis91 min

Nearby

Mesoscale Discussions in Missouri, 2012Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Oklahoma, 2012Every mesoscale discussion in 2012

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.