Alert archive / Tennessee / Mesoscale Discussions in 2020
Mesoscale Discussion 320
The Storm Prediction Center issued this mesoscale discussion at Apr 8, 2020, 9:52 PM CDT for 4 states. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Apr 8, 2020, 9:52 PM CDT (02:52 UTC)
- Expired
- Apr 8, 2020, 11:45 PM CDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
All 66 counties
Colbert County, AL, DeKalb County, AL, Jackson County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Dade County, GA, Dawson County, GA, Fannin County, GA, Floyd County, GA, Gilmer County, GA, Gordon County, GA, Lumpkin County, GA, Murray County, GA, Pickens County, GA, Union County, GA, Walker County, GA, Whitfield County, GA, Cherokee County, NC, Clay County, NC, Graham County, NC, Anderson County, TN, Bedford County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Cannon County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, DeKalb County, TN, Fentress County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hamilton County, TN, Jackson County, TN, Knox County, TN, Lincoln County, TN, Loudon County, TN, Marion County, TN, Marshall County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Moore County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Polk County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Smith County, TN, Van Buren County, TN, Warren County, TN, White County, TN
The radar
The Northeast Alabama radar (KHTX), 51 km from the middle of the area, began a volume at 02:51 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 00:00Z, 2.9 hours before the alert went out and 139 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.
- Mixed-layer CAPE
- 990 J/kg
- Mixed-layer CIN
- -46 J/kg
- Mixed-layer LCL
- 1332 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- 75 m²/s²
- 0-3 km storm-relative helicity
- 124 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.2
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 |
|---|---|---|---|---|
| Apr 8, 10:16 PM CDT | Severe Thunderstorm Watch | SPC | Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more | 6 hr |
| Apr 9, 1:10 AM CDT | Mesoscale Discussion | SPC | Blount, Cherokee, Colbert, Cullman, DeKalb, Etowah and 14 more | 95 min |
| Apr 9, 1:03 AM CDT | Severe Thunderstorm Watch | SPC | Alleghany, Ashe, Watauga | 3 hr |
| Apr 9, 2:36 AM CDT | Mesoscale Discussion | SPC | Alleghany, Ashe, Stokes, Surry | 84 min |
| Apr 8, 7:04 PM CDT | Tornado Watch | SPC | Benton, Carroll, Cheatham, Chester, Crockett, Davidson and 37 more | 7 hr |
Nearby
Mesoscale Discussions in Tennessee, 2020Mesoscale Discussions in Georgia, 2020Mesoscale Discussions in Alabama, 2020Every mesoscale discussion in 2020
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.