Alert archive / Virginia / Mesoscale Discussions in 2009

Mesoscale Discussion 563

April 25, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2009, 2:46 PM EDT for 4 states. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Apr 25, 2009, 2:46 PM EDT (18:46 UTC)
Expired: Apr 25, 2009, 3:45 PM EDT
In force: 59 min
Issued by: the Storm Prediction Center

All 51 counties

Alleghany County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Jackson County, NC, Macon County, NC, Madison County, NC, Mitchell County, NC, Swain County, NC, Watauga County, NC, Yancey County, NC, Carter County, TN, Cocke County, TN, Johnson County, TN, Sevier County, TN, Unicoi County, TN, Washington County, TN, Alleghany County, VA, Augusta County, VA, Bath County, VA, Bland County, VA, Botetourt County, VA, Carroll County, VA, City of Buena Vista, VA, City of Covington, VA, City of Galax, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, Craig County, VA, Floyd County, VA, Giles County, VA, Grayson County, VA, Highland County, VA, Montgomery County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Smyth County, VA, Wythe County, VA, Hardy County, WV, Monroe County, WV, Pendleton County, WV

The radar

The Roanoke radar (KFCX), 124 km from the middle of the area, began a volume at 18:49 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

Cncnati-Daytn, OH (KILN), launched 12:00Z, 6.8 hours before the alert went out and 371 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: 156 J/kg
Mixed-layer CIN: -217 J/kg
Mixed-layer LCL: 1506 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: 75 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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>

Nearby

Mesoscale Discussions in Virginia, 2009 Mesoscale Discussions in North Carolina, 2009 Mesoscale Discussions in Tennessee, 2009 Every mesoscale discussion in 2009

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.