Alert archive / Alabama / Mesoscale Discussions in 2008

Mesoscale Discussion 953

May 20, 200823 counties in Alabama; Monroe County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 20, 2008, 3:00 PM CDT for 23 counties in Alabama; Monroe County, Mississippi. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: May 20, 2008, 3:00 PM CDT (20:00 UTC)
Expired: May 20, 2008, 4:00 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center

All 24 counties

Blount County, AL, Calhoun County, AL, Cherokee County, AL, Clay County, AL, Cleburne County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Jefferson County, AL, Lamar County, AL, Lawrence County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Pickens County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Monroe County, MS

The radar

The Birmingham radar (KBMX), 90 km from the middle of the area, began a volume at 20:00 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.

Severe Thunderstorm Watch 330May 20, 3:30 PM CDT

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 8.0 hours before the alert went out and 89 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: 698 J/kg
Mixed-layer CIN: -197 J/kg
Mixed-layer LCL: 982 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 305 m²/s²
0-3 km storm-relative helicity: 356 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
May 20, 3:31 PM CDT	Severe Thunderstorm Watch	SPC	Bibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 20 more	6 hr
May 20, 6:19 PM CDT	Mesoscale Discussion	SPC	Bibb, Blount, Calhoun, Chambers, Clay, Cleburne and 9 more	86 min
May 20, 4:45 PM CDT	Mesoscale Discussion	SPC	Calhoun, Chickasaw, Choctaw, Clay, Itawamba, Lee and 6 more	60 min

Nearby

Mesoscale Discussions in Alabama, 2008 Mesoscale Discussions in Mississippi, 2008 Every mesoscale discussion in 2008

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.