Alert archive / Maryland / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 214, NWS Baltimore/Washington

August 12, 2017Allegany County, Washington County, Maryland; Morgan County, West Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Aug 12, 2017, 1:45 PM EDT for Allegany County, Washington County, Maryland; Morgan County, West Virginia. It was in force for 28 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: Aug 12, 2017, 1:45 PM EDT (17:45 UTC)
Expired: Aug 12, 2017, 2:13 PM EDT
In force: 28 min
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Allegany County, MD, Washington County, MD, Morgan County, WV

The radar

The Sterling radar (KLWX), 96 km from the middle of the area, began a volume at 17:47 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.8 hours before the alert went out and 103 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: 248 J/kg
Mixed-layer CIN: -78 J/kg
Mixed-layer LCL: 772 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 78 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Baltimore/Washington wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 12, 10:38 AM EDT, 3 hours 7 minutes earlier.

Area forecast discussion, Aug 12, 10:38 AM EDT, 3 hours 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>

Hazardous weather outlook, Aug 12, 9:13 AM EDT, 4 hours 32 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, Aug 12, 8:08 AM EDT, 5 hours 37 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, Aug 12, 8:23 AM EDT, 5 hours 22 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, Aug 12, 12:09 PM EDT, 1 hour 36 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, Aug 12, 12:28 PM EDT, 1 hour 17 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 Baltimore/Washington issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 11, 8:11 PM EDT	Flash Flood Warning	LWX	Fauquier	3 hr
Aug 11, 8:47 PM EDT	Flash Flood Warning	LWX	Fairfax, Prince William, City of Manassas Park	3 hr
Aug 11, 9:51 PM EDT	Special Marine Warning	LWX		114 min
Aug 11, 9:52 PM EDT	Small Craft Advisory	LWX		4 hr
Aug 11, 10:18 PM EDT	Areal Flood Warning	LWX	Fairfax, Prince William, City of Manassas, City of Manassas Park	6 hr
Aug 11, 11:24 PM EDT	Special Marine Warning	LWX		96 min
Aug 11, 11:40 PM EDT	Special Marine Warning	LWX		65 min
Aug 12, 12:57 AM EDT	Special Marine Warning	LWX		63 min
Aug 12, 4:27 AM EDT	Areal Flood Warning	LWX	Prince William, City of Manassas, City of Manassas Park	5 hr
Aug 12, 6:58 AM EDT	Special Marine Warning	LWX		92 min
Aug 12, 9:25 AM EDT	Areal Flood Warning	LWX	Prince William, City of Manassas, City of Manassas Park	6 hr
Aug 12, 5:58 PM EDT	Severe Thunderstorm Warning	LWX	Loudoun	47 min
Aug 12, 6:25 PM EDT	Special Marine Warning	LWX		2 hr
Aug 12, 6:30 PM EDT	Severe Thunderstorm Warning	LWX	Loudoun	17 min
Aug 12, 6:34 PM EDT	Special Marine Warning	LWX		116 min
Aug 12, 7:32 PM EDT	Severe Thunderstorm Warning	LWX	Arlington, Fairfax, City of Alexandria, City of Falls Church	43 min
Aug 12, 7:43 PM EDT	Special Marine Warning	LWX		2 hr
Aug 11, 9:18 PM EDT	Flash Flood Warning	LWX	Prince George's	3 hr
Aug 11, 10:48 PM EDT	Flash Flood Warning	LWX	Calvert, Charles, Prince George's, Saint Mary's	3 hr
Aug 11, 11:55 PM EDT	Areal Flood Warning	LWX	Prince George's	6 hr
Aug 12, 2:51 PM EDT	Coastal Flood Advisory	LWX	Saint Mary's	5 hr
Aug 12, 3:26 PM EDT	Severe Thunderstorm Warning	LWX	Allegany, Washington	39 min
Aug 12, 3:50 PM EDT	Severe Thunderstorm Warning	LWX	Washington	40 min
Aug 12, 5:00 PM EDT	Severe Thunderstorm Warning	LWX	Frederick, Washington	45 min
Aug 12, 5:56 PM EDT	Severe Thunderstorm Warning	LWX	Carroll, Frederick, Howard, Montgomery	49 min
Aug 12, 7:19 PM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel, Baltimore, Howard, City of Baltimore	41 min
Aug 12, 7:56 PM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel	49 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2017 Severe Thunderstorm Warnings in West Virginia, 2017 Every severe thunderstorm warning in 2017

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.