Alert archive / Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 1270

June 25, 2012Sussex County, Delaware; 12 counties in Maryland; 37 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jun 25, 2012, 10:44 AM EDT for Sussex County, Delaware; 12 counties in Maryland; 37 counties in Virginia. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: Jun 25, 2012, 10:44 AM EDT (14:44 UTC)
Expired: Jun 25, 2012, 11:45 AM EDT
In force: 61 min
Issued by: the Storm Prediction Center

All 50 counties

Sussex County, DE, Anne Arundel County, MD, Calvert County, MD, Caroline County, MD, Charles County, MD, Dorchester County, MD, Kent County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Accomack County, VA, Amelia County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Hampton, VA, City of Hopewell, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Williamsburg, VA, Essex County, VA, Gloucester County, VA, Hanover County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Powhatan County, VA, Prince George County, VA, Richmond County, VA, Surry County, VA, Westmoreland County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 102 km from the middle of the area, began a volume at 14:43 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 426Jun 25, 12:55 PM EDT

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 2.7 hours before the alert went out and 115 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: 851 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 1274 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 60 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

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 25, 6:39 AM EDT	Severe Thunderstorm Watch	SPC	New Castle	7 hr
Jun 25, 12:55 PM EDT	Severe Thunderstorm Watch	SPC	Dorchester, Saint Mary's, Somerset, Wicomico, Worcester	6 hr
Jun 25, 3:57 PM EDT	Mesoscale Discussion	SPC	Saint Mary's, Somerset, Wicomico, Worcester	63 min

Nearby

Mesoscale Discussions in Virginia, 2012 Mesoscale Discussions in Maryland, 2012 Mesoscale Discussions in Delaware, 2012 Every mesoscale discussion in 2012

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.