Alert archive / Tennessee / Mesoscale Discussions in 2016

Mesoscale Discussion 476

April 27, 20164 states

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2016, 3:28 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 27, 2016, 3:28 PM CDT (20:28 UTC)
Expired
Apr 27, 2016, 5:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 39 counties

Colbert County, AL, Cullman County, AL, Fayette County, AL, Franklin County, AL, Jefferson County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Marion County, AL, Morgan County, AL, Walker County, AL, Winston County, AL, Calloway County, KY, Graves County, KY, Trigg County, KY, Tishomingo County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Decatur County, TN, Dickson County, TN, Gibson County, TN, Giles County, TN, Hardin County, TN, Henderson County, TN, Henry County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Madison County, TN, Maury County, TN, McNairy County, TN, Obion County, TN, Perry County, TN, Stewart County, TN, Wayne County, TN, Weakley County, TN

The radar

The Nashville radar (KOHX), 157 km from the middle of the area, began a volume at 20:28 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.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 8.5 hours before the alert went out and 147 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, Nashville Metro, TN at 12:00Z on 2016-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 669 joules per kilogram.LCLLFCEL10008507005003002001001 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, Nashville Metro, TN at 12:00Z on 2016-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 122 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
669 J/kg
Mixed-layer CIN
-79 J/kg
Mixed-layer LCL
828 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
122 m²/s²
0-3 km storm-relative helicity
166 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

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.

IssuedProductOfficeCountiesLasted
Apr 27, 1:34 PM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Greene, Hale, Lamar and 6 more2 hr
Apr 26, 7:20 PM CDTMesoscale DiscussionSPCAdair, Allen, Anderson, Barren, Bath, Boone and 89 more55 min
Apr 27, 5:11 PM CDTTornado WatchSPCBreckinridge, Butler, Caldwell, Christian, Crittenden, Daviess and 16 more3 hr
Apr 27, 7:30 AM CDTMesoscale DiscussionSPCAdams, Wilkinson2 hr
Apr 27, 7:54 AM CDTSevere Thunderstorm WatchSPCAdams, Amite, Claiborne, Copiah, Covington, Forrest and 20 more7 hr

Nearby

Mesoscale Discussions in Tennessee, 2016Mesoscale Discussions in Alabama, 2016Mesoscale Discussions in Kentucky, 2016Every mesoscale discussion in 2016

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.