Alert archive / Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 318

March 21, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Mar 21, 2012, 1:22 PM EDT for 4 states. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: Mar 21, 2012, 1:22 PM EDT (17:22 UTC)
Expired: Mar 21, 2012, 3:15 PM EDT
In force: 113 min
Issued by: the Storm Prediction Center

All 119 counties

Alamance County, NC, Alexander County, NC, Alleghany County, NC, Ashe County, NC, Cabarrus County, NC, Caldwell County, NC, Caswell County, NC, Catawba County, NC, Chatham County, NC, Cumberland County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hoke County, NC, Iredell County, NC, Johnston County, NC, Lee County, NC, Lenoir County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Richmond County, NC, Rockingham County, NC, Rowan County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Stokes County, NC, Surry County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Watauga County, NC, Wayne County, NC, Wilkes County, NC, Wilson County, NC, Yadkin County, NC, Johnson County, TN, Albemarle County, VA, Alleghany County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Carroll County, VA, Charlotte County, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Covington, VA, City of Danville, VA, City of Emporia, VA, City of Galax, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, Craig County, VA, Cumberland County, VA, Dinwiddie County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Giles County, VA, Grayson County, VA, Greensville County, VA, Halifax County, VA, Henry County, VA, Highland County, VA, Lunenburg County, VA, Mecklenburg County, VA, Montgomery County, VA, Nelson County, VA, Nottoway County, VA, Patrick County, VA, Pittsylvania County, VA, Prince Edward County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Smyth County, VA, Tazewell County, VA, Wythe County, VA, Fayette County, WV, Greenbrier County, WV, McDowell County, WV, Mercer County, WV, Monroe County, WV, Nicholas County, WV, Pendleton County, WV, Pocahontas County, WV, Raleigh County, WV, Randolph County, WV, Summers County, WV, Webster County, WV, Wyoming County, WV

The radar

The Roanoke radar (KFCX), 58 km from the middle of the area, began a volume at 17:22 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

Roanoke, VA (KRNK), launched 12:00Z, 5.4 hours before the alert went out and 38 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: 197 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 743 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 33 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>

Nearby

Mesoscale Discussions in Virginia, 2012 Mesoscale Discussions in North Carolina, 2012 Mesoscale Discussions in West Virginia, 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.