Alert archive / Virginia / Mesoscale Discussions in 2013

Mesoscale Discussion 993

June 7, 2013Somerset County, Wicomico County, Maryland; 9 counties in North Carolina; 22 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jun 7, 2013, 6:40 PM EDT for Somerset County, Wicomico County, Maryland; 9 counties in North Carolina; 22 counties in Virginia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 7, 2013, 6:40 PM EDT (22:40 UTC)
Expired: Jun 7, 2013, 8:45 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 33 counties

Somerset County, MD, Wicomico County, MD, Bertie County, NC, Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Hertford County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Accomack County, VA, City of Chesapeake, VA, City of Franklin, VA, City of Hampton, VA, City of Newport News, VA, City of Norfolk, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Gloucester County, VA, Isle of Wight County, VA, James City County, VA, Lancaster County, VA, Mathews County, VA, Middlesex County, VA, Northampton County, VA, Northumberland County, VA, Southampton County, VA, Surry County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 66 km from the middle of the area, began a volume at 22:39 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.7 hours before the alert went out and 116 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: 45 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 596 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

<!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
Jun 7, 1:00 PM EDT	Tornado Watch	SPC	Somerset, Wicomico, Worcester	7 hr
Jun 7, 3:32 PM EDT	Mesoscale Discussion	SPC	Somerset, Wicomico, Worcester	58 min
Jun 7, 12:49 AM EDT	Mesoscale Discussion	SPC	Brunswick, New Hanover	56 min
Jun 7, 3:34 AM EDT	Mesoscale Discussion	SPC	Beaufort, Carteret, Craven, Dare, Hyde, Jones and 4 more	2 hr
Jun 7, 5:37 AM EDT	Tornado Watch	SPC	Beaufort, Bertie, Camden, Carteret, Chowan, Craven and 23 more	7 hr
Jun 7, 8:35 AM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Camden, Carteret, Chowan, Craven and 23 more	85 min
Jun 7, 11:26 AM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Camden, Carteret, Chowan and 22 more	64 min

Nearby

Mesoscale Discussions in Virginia, 2013 Mesoscale Discussions in North Carolina, 2013 Mesoscale Discussions in Maryland, 2013 Every mesoscale discussion in 2013

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.