Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 201, NWS Norman, OK

April 28, 2020Johnston County, Murray County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 28, 2020, 9:06 PM CDT for Johnston County, Murray County, Oklahoma. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 28, 2020, 9:06 PM CDT (02:06 UTC)
Expired: Apr 28, 2020, 9:45 PM CDT
In force: 39 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Johnston County, OK, Murray County, OK

The radar

The Norman radar (KTLX), 110 km from the middle of the area, began a volume at 02:08 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 28, 3:30 PM CDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 2.1 hours before the alert went out and 104 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: 4384 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 1364 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 11.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Norman, OK wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 28, 6:15 PM CDT, 2 hours 51 minutes earlier.

Area forecast discussion, Apr 28, 6:15 PM CDT, 2 hours 51 minutes before

<!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>

Hazardous weather outlook, Apr 28, 6:27 PM CDT, 2 hours 39 minutes before

<!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>

In the hours before

Local storm report, Apr 28, 8:23 PM CDT, 43 minutes before

<!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>

Local storm report, Apr 28, 8:27 PM CDT, 39 minutes before

<!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>

Local storm report, Apr 28, 8:28 PM CDT, 38 minutes before

<!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>

Local storm report, Apr 28, 8:32 PM CDT, 34 minutes before

<!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>

Local storm report, Apr 28, 8:57 PM CDT, 9 minutes before

<!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>

Local storm report, Apr 28, 8:58 PM CDT, 8 minutes before

<!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>

The office that day

Everything else NWS Norman, OK issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 28, 7:06 PM CDT	Severe Thunderstorm Warning	OUN	Grady, Stephens	39 min
Apr 28, 7:19 PM CDT	Severe Thunderstorm Warning	OUN	Lincoln, Pottawatomie, Seminole	41 min
Apr 28, 7:30 PM CDT	Severe Thunderstorm Warning	OUN	Garvin, McClain	30 min
Apr 28, 7:31 PM CDT	Severe Thunderstorm Warning	OUN	Lincoln, Pottawatomie, Seminole	44 min
Apr 28, 7:41 PM CDT	Special Weather Statement	OUN	Atoka	34 min
Apr 28, 7:43 PM CDT	Severe Thunderstorm Warning	OUN	Grady, Stephens	47 min
Apr 28, 7:47 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Pottawatomie, Seminole	43 min
Apr 28, 7:52 PM CDT	Severe Thunderstorm Warning	OUN	Cotton, Jefferson, Stephens	38 min
Apr 28, 7:57 PM CDT	Severe Thunderstorm Warning	OUN	Hughes, Seminole	33 min
Apr 28, 8:11 PM CDT	Severe Thunderstorm Warning	OUN	Hughes, Pontotoc, Seminole	34 min
Apr 28, 8:25 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Cotton, Jefferson, Stephens	50 min
Apr 28, 8:29 PM CDT	Severe Thunderstorm Warning	OUN	Coal, Hughes, Pontotoc, Seminole	46 min
Apr 28, 8:47 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Love, Murray	43 min
Apr 28, 8:50 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Jefferson, Love, Stephens	55 min
Apr 28, 9:04 PM CDT	Severe Thunderstorm Warning	OUN	Atoka, Coal, Hughes, Johnston, Pontotoc	41 min
Apr 28, 9:29 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Love, Marshall	46 min
Apr 28, 9:43 PM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan, Coal, Johnston, Marshall	62 min
Apr 29, 10:16 AM CDT	Wind Advisory	OUN	Alfalfa, Blaine, Canadian, Custer, Dewey, Ellis and 10 more	3 hr
Apr 28, 8:45 PM CDT	Severe Thunderstorm Warning	OUN	Clay	45 min
Apr 28, 9:03 PM CDT	Severe Thunderstorm Warning	OUN	Clay	27 min
Apr 28, 9:27 PM CDT	Severe Thunderstorm Warning	OUN	Archer, Clay	48 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2020 Every severe thunderstorm warning 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.