Alert archive / Texas / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 28, NWS Houston/Galveston, TX

April 18, 2020Liberty County, Texas

NWS Houston/Galveston, TX issued this severe thunderstorm warning at Apr 18, 2020, 5:50 PM CDT for Liberty County, Texas. It was in force for 40 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 18, 2020, 5:50 PM CDT (22:50 UTC)
Expired: Apr 18, 2020, 6:30 PM CDT
In force: 40 min
Issued by: NWS Houston/Galveston, TX
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

County Liberty County, TX

The radar

The Houston radar (KHGX), 80 km from the middle of the area, began a volume at 22:50 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 10.8 hours before the alert went out and 155 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: 334 J/kg
Mixed-layer CIN: -142 J/kg
Mixed-layer LCL: 519 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 171 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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 Houston/Galveston, TX wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 18, 3:40 PM CDT, 2 hours 10 minutes earlier.

Area forecast discussion, Apr 18, 3:40 PM CDT, 2 hours 10 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 18, 4:42 PM CDT, 1 hour 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>

Special weather statement, Apr 18, 4:43 PM CDT, 1 hour 7 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 18, 4:44 PM CDT, 1 hour 6 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>

Special weather statement, Apr 18, 4:47 PM CDT, 1 hour 3 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 18, 4:54 PM CDT, 56 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>

Special weather statement, Apr 18, 5:32 PM CDT, 18 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 Houston/Galveston, TX issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 17, 7:18 PM CDT	Special Marine Warning	HGX		42 min
Apr 17, 8:00 PM CDT	Special Marine Warning	HGX		60 min
Apr 17, 9:02 PM CDT	Special Marine Warning	HGX		28 min
Apr 17, 11:20 PM CDT	Special Marine Warning	HGX		40 min
Apr 18, 2:50 PM CDT	Special Weather Statement	HGX	Austin, Waller	25 min
Apr 18, 3:22 PM CDT	Special Weather Statement	HGX	Waller	38 min
Apr 18, 3:35 PM CDT	Severe Thunderstorm Warning	HGX	Fort Bend, Harris, Waller	25 min
Apr 18, 3:40 PM CDT	Severe Thunderstorm Warning	HGX	Grimes, Montgomery, Waller	35 min
Apr 18, 3:42 PM CDT	Special Weather Statement	HGX	Chambers	48 min
Apr 18, 3:54 PM CDT	Severe Thunderstorm Warning	HGX	Harris	36 min
Apr 18, 4:06 PM CDT	Severe Thunderstorm Warning	HGX	Grimes, Montgomery, Walker	39 min
Apr 18, 4:35 PM CDT	Severe Thunderstorm Warning	HGX	Polk, San Jacinto, Trinity, Walker	55 min
Apr 18, 4:43 PM CDT	Special Weather Statement	HGX	Washington	47 min
Apr 18, 4:47 PM CDT	Special Weather Statement	HGX	Harris	43 min
Apr 18, 5:03 PM CDT	Areal Flood Advisory	HGX	Harris, Montgomery	57 min
Apr 18, 5:18 PM CDT	Severe Thunderstorm Warning	HGX	Harris, Liberty, Montgomery	30 min
Apr 18, 5:27 PM CDT	Severe Thunderstorm Warning	HGX	Chambers, Harris, Liberty	33 min
Apr 18, 5:32 PM CDT	Special Weather Statement	HGX	Montgomery	28 min
Apr 18, 5:59 PM CDT	Severe Thunderstorm Warning	HGX	Liberty, Montgomery, San Jacinto	46 min
Apr 18, 6:31 PM CDT	Special Weather Statement	HGX	Liberty	44 min

Nearby

Severe Thunderstorm Warnings in Texas, 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.