Alert archive / Alabama / Mesoscale Discussions in 2015

Mesoscale Discussion 1979

November 18, 201520 counties in Alabama; 4 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Nov 18, 2015, 7:22 AM CST for 20 counties in Alabama; 4 counties in Florida. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Nov 18, 2015, 7:22 AM CST (13:22 UTC)
Expired: Nov 18, 2015, 8:45 AM CST
In force: 83 min
Issued by: the Storm Prediction Center

All 24 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Butler County, AL, Chilton County, AL, Clarke County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dallas County, AL, Escambia County, AL, Hale County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Perry County, AL, Shelby County, AL, Tuscaloosa County, AL, Wilcox County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL

The radar

The Mobile radar (KMOB), 147 km from the middle of the area, began a volume at 13:25 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 552Nov 18, 8:25 AM CST

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 1.4 hours before the alert went out and 173 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: 19 J/kg
Mixed-layer CIN: -274 J/kg
Mixed-layer LCL: 931 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 475 m²/s²
0-3 km storm-relative helicity: 594 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
Nov 18, 1:14 AM CST	Mesoscale Discussion	SPC	Choctaw, Clarke, Fayette, Greene, Hale, Lamar and 8 more	2 hr
Nov 18, 2:49 AM CST	Tornado Watch	SPC	Baldwin, Choctaw, Clarke, Greene, Hale, Marengo and 4 more	6 hr
Nov 18, 5:21 AM CST	Mesoscale Discussion	SPC	Baldwin, Choctaw, Clarke, Dallas, Fayette, Greene and 9 more	114 min
Nov 18, 8:25 AM CST	Tornado Watch	SPC	Autauga, Baldwin, Barbour, Bullock, Butler, Clarke and 22 more	8 hr
Nov 18, 10:51 AM CST	Mesoscale Discussion	SPC	Autauga, Baldwin, Barbour, Bullock, Butler, Coffee and 17 more	114 min
Nov 18, 1:39 PM CST	Mesoscale Discussion	SPC	Barbour, Coffee, Covington, Crenshaw, Dale, Geneva and 3 more	2 hr
Nov 18, 2:16 PM CST	Tornado Watch	SPC	Coffee, Dale, Geneva, Henry, Houston	6 hr
Nov 18, 5:35 PM CST	Mesoscale Discussion	SPC	Franklin, Gadsden, Gulf, Jefferson, Leon, Liberty and 1 more	115 min

Nearby

Mesoscale Discussions in Alabama, 2015 Mesoscale Discussions in Florida, 2015 Every mesoscale discussion in 2015

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.