Alert archive / Virginia / Mesoscale Discussions in 2018

Mesoscale Discussion 417

May 14, 20187 counties in Maryland; 36 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at May 14, 2018, 7:22 PM EDT for 7 counties in Maryland; 36 counties in Virginia. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: May 14, 2018, 7:22 PM EDT (23:22 UTC)
Expired: May 14, 2018, 8:15 PM EDT
In force: 53 min
Issued by: the Storm Prediction Center

All 43 counties

Anne Arundel County, MD, Calvert County, MD, Charles County, MD, Howard County, MD, Prince George's County, MD, Saint Mary's County, MD, Talbot County, MD, Amelia County, VA, Amherst County, VA, Arlington County, VA, Buckingham County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Colonial Heights, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Hopewell, VA, City of Richmond, VA, Cumberland County, VA, Essex County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland County, VA, Hanover County, VA, Henrico County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northumberland County, VA, Powhatan County, VA, Prince Edward County, VA, Richmond County, VA, Spotsylvania County, VA, Stafford County, VA, Westmoreland County, VA

The radar

The Sterling radar (KLWX), 102 km from the middle of the area, began a volume at 23:21 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, 11.4 hours before the alert went out and 102 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 828 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 138 m²/s²
0-3 km storm-relative helicity: 136 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
May 14, 11:56 AM EDT	Mesoscale Discussion	SPC	Allegany, Carroll, Frederick, Garrett, Howard, Montgomery and 1 more	64 min
May 14, 12:29 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 9 more	9 hr
May 14, 3:26 PM EDT	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 10 more	2 hr
May 14, 5:37 PM EDT	Mesoscale Discussion	SPC	Somerset	53 min
May 14, 6:11 PM EDT	Severe Thunderstorm Watch	SPC	Dorchester, Somerset, Wicomico, Worcester	4 hr

Nearby

Mesoscale Discussions in Virginia, 2018 Mesoscale Discussions in Maryland, 2018 Every mesoscale discussion in 2018

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.