Alert archive / Kentucky / Mesoscale Discussions in 2012

Mesoscale Discussion 1918

September 7, 20126 states

The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2012, 3:44 PM CDT for 6 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 7, 2012, 3:44 PM CDT (20:44 UTC)
Expired
Sep 7, 2012, 5:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 50 counties

Clay County, AR, Greene County, AR, Mississippi County, AR, Alexander County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Johnson County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, White County, IL, Williamson County, IL, Posey County, IN, Vanderburgh County, IN, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Henderson County, KY, Hickman County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Ripley County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO, Dyer County, TN, Lake County, TN, Lauderdale County, TN, Obion County, TN, Weakley County, TN

The radar

The Paducah radar (KPAH), 50 km from the middle of the area, began a volume at 20:46 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

Little Rock, AR (KLZK), launched 12:00Z, 8.7 hours before the alert went out and 273 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, Little Rock, AR at 12:00Z on 2012-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2161 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, Little Rock, AR at 12:00Z on 2012-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 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
2161 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
1014 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
30 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.7

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
Sep 7, 2:35 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more6 hr
Sep 7, 3:09 PM CDTMesoscale DiscussionSPCBaxter, Cleburne, Conway, Craighead, Cross, Faulkner and 28 more66 min
Sep 7, 5:15 PM CDTSevere Thunderstorm WatchSPCArkansas, Baxter, Boone, Clay, Cleburne, Conway and 40 more7 hr
Sep 7, 6:06 PM CDTMesoscale DiscussionSPCBaxter, Boone, Carroll, Crawford, Franklin, Fulton and 9 more84 min
Sep 7, 10:09 AM CDTMesoscale DiscussionSPCClark, Coles, Crawford, Cumberland, Douglas, Edgar and 5 more2 hr
Sep 7, 3:22 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Clark, Coles, Crawford and 23 more53 min
Sep 7, 3:41 PM CDTSevere Thunderstorm WatchSPCChristian, Clark, Clay, Coles, Crawford, Cumberland and 8 more6 hr
Sep 7, 10:36 AM CDTSevere Thunderstorm WatchSPCAdams, Allen, Blackford, Boone, Carroll, Cass and 38 more6 hr
Sep 7, 12:16 PM CDTMesoscale DiscussionSPCAdams, Delaware, Fayette, Hancock, Henry, Jay and 4 more59 min
Sep 7, 1:16 PM CDTMesoscale DiscussionSPCFayette, Henry, Randolph, Rush, Union, Wayne59 min
Sep 7, 2:39 PM CDTMesoscale DiscussionSPCDearborn, Franklin, Union66 min
Sep 7, 1:41 PM CDTMesoscale DiscussionSPCAudrain, Barry, Barton, Bates, Benton, Boone and 47 more94 min

Nearby

Mesoscale Discussions in Kentucky, 2012Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Missouri, 2012Every mesoscale discussion in 2012

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.