Alert archive / Arkansas / Mesoscale Discussions in 2020

Mesoscale Discussion 498

April 28, 20206 states

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2020, 11:12 PM CDT for 6 states. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Apr 28, 2020, 11:12 PM CDT (04:12 UTC)
Expired: Apr 29, 2020, 12:15 AM CDT
In force: 63 min
Issued by: the Storm Prediction Center

All 51 counties

Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Cleveland County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, Prairie County, AR, St. Francis County, AR, Hardin County, IL, Johnson County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Ballard County, KY, Carlisle County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, Livingston County, KY, Marshall County, KY, McCracken County, KY, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Coahoma County, MS, DeSoto County, MS, Quitman County, MS, Tate County, MS, Tunica County, MS, Crockett County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Haywood County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 75 km from the middle of the area, began a volume at 04:14 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 nearest sounding before it

Little Rock, AR (KLZK), launched 00:00Z, 4.2 hours before the alert went out and 86 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: 457 J/kg
Mixed-layer CIN: -179 J/kg
Mixed-layer LCL: 1081 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 164 m²/s²
0-3 km storm-relative helicity: 227 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.2

Open this sounding in Storm Lab

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 28, 7:35 PM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Baxter, Boone, Bradley, Calhoun, Clark and 51 more	7 hr
Apr 28, 8:06 PM CDT	Mesoscale Discussion	SPC	Lafayette, Little River, Miller, Sevier	54 min
Apr 28, 8:25 PM CDT	Severe Thunderstorm Watch	SPC	Columbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more	9 hr
Apr 28, 10:08 PM CDT	Mesoscale Discussion	SPC	Clark, Cleburne, Conway, Craighead, Faulkner, Garland and 15 more	97 min
Apr 28, 11:57 PM CDT	Mesoscale Discussion	SPC	Ashley, Chicot	63 min
Apr 29, 12:48 AM CDT	Severe Thunderstorm Watch	SPC	Ashley, Chicot	4 hr
Apr 28, 9:06 PM CDT	Mesoscale Discussion	SPC	Bond, Christian, Clinton, Coles, Cumberland, Douglas and 15 more	84 min
Apr 29, 2:40 AM CDT	Severe Thunderstorm Watch	SPC	Amite, Wilkinson	6 hr
Apr 28, 7:20 PM CDT	Mesoscale Discussion	SPC	Greene, Webster, Wright	25 min

Nearby

Mesoscale Discussions in Arkansas, 2020 Mesoscale Discussions in Tennessee, 2020 Mesoscale Discussions in Kentucky, 2020 Every 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.