Alert archive / Georgia / Mesoscale Discussions in 2009

Mesoscale Discussion 533

April 19, 200918 counties in Alabama; 41 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2009, 10:21 PM CDT for 18 counties in Alabama; 41 counties in Georgia. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Apr 19, 2009, 10:21 PM CDT (03:21 UTC)
Expired
Apr 19, 2009, 11:45 PM CDT
In force
84 min
Issued by
the Storm Prediction Center
All 59 counties

Autauga County, AL, Bullock County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Elmore County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Montgomery County, AL, Randolph County, AL, Russell County, AL, Talladega County, AL, Tallapoosa County, AL, Barrow County, GA, Bartow County, GA, Butts County, GA, Carroll County, GA, Chattooga County, GA, Cherokee County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Floyd County, GA, Forsyth County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Gwinnett County, GA, Hall County, GA, Haralson County, GA, Harris County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Lamar County, GA, Lumpkin County, GA, Meriwether County, GA, Muscogee County, GA, Newton County, GA, Paulding County, GA, Pickens County, GA, Pike County, GA, Polk County, GA, Rockdale County, GA, Spalding County, GA, Talbot County, GA, Troup County, GA, Upson County, GA, Walker County, GA, Walton County, GA

The radar

The Atlanta radar (KFFC), 51 km from the middle of the area, began a volume at 03:22 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

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 3.4 hours before the alert went out and 57 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, Peachtre/Fal Fld, GA at 00:00Z on 2009-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 182 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, Peachtre/Fal Fld, GA at 00:00Z on 2009-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 212 square meters per square second.1939587897117Sfc1 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
182 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
1004 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
212 m²/s²
0-3 km storm-relative helicity
248 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.0

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
Apr 19, 7:27 PM CDTMesoscale DiscussionSPCBlount, Cullman, DeKalb, Madison, Marshall, Morgan and 1 more63 min
Apr 19, 8:19 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Bullock, Calhoun, Chambers, Cherokee and 18 more56 min
Apr 19, 8:45 PM CDTTornado WatchSPCAutauga, Barbour, Bibb, Bullock, Calhoun, Chambers and 22 more4 hr
Apr 20, 12:22 AM CDTMesoscale DiscussionSPCBullock, Butler, Chambers, Crenshaw, Elmore, Lee and 6 more53 min
Apr 19, 7:51 PM CDTTornado WatchSPCBarrow, Bartow, Butts, Carroll, Catoosa, Chattooga and 42 more6 hr
Apr 19, 11:20 PM CDTMesoscale DiscussionSPCElbert, Franklin, Greene, Hart, Lincoln, McDuffie and 4 more55 min
Apr 19, 11:42 PM CDTTornado WatchSPCBaldwin, Banks, Clarke, Columbia, Elbert, Franklin and 19 more5 hr
Apr 20, 1:52 PM CDTMesoscale DiscussionSPCChatham83 min
Apr 20, 2:16 PM CDTSevere Thunderstorm WatchSPCBryan, Chatham, Effingham, Liberty, Long, McIntosh6 hr
Apr 20, 3:55 PM CDTMesoscale DiscussionSPCBryan, Bulloch, Chatham, Effingham, Evans, Liberty and 1 more95 min
Apr 20, 6:36 PM CDTMesoscale DiscussionSPCChatham84 min

Nearby

Mesoscale Discussions in Georgia, 2009Mesoscale Discussions in Alabama, 2009Every mesoscale discussion in 2009

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.