Alert archive / Virginia / Mesoscale Discussions in 2007

Mesoscale Discussion 1778

August 17, 200727 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 17, 2007, 2:39 PM EDT for 27 counties in Virginia. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: Aug 17, 2007, 2:39 PM EDT (18:39 UTC)
Expired: Aug 17, 2007, 3:45 PM EDT
In force: 66 min
Issued by: the Storm Prediction Center

All 27 counties

Albemarle County, VA, Buckingham County, VA, Caroline County, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Fredericksburg, VA, City of Manassas, VA, City of Manassas Park, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, King George County, VA, Louisa County, VA, Madison County, VA, Nelson County, VA, Orange County, VA, Powhatan County, VA, Prince William County, VA, Rappahannock County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.7 hours before the alert went out and 75 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: 352 J/kg
Mixed-layer CIN: -115 J/kg
Mixed-layer LCL: 1022 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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
Aug 16, 10:04 PM EDT	Mesoscale Discussion	SPC	Albemarle, Alleghany, Amelia, Amherst, Appomattox, Augusta and 69 more	56 min
Aug 16, 11:07 PM EDT	Severe Thunderstorm Watch	SPC	Accomack, Arlington, Caroline, Clarke, Culpeper, Essex and 36 more	4 hr

Nearby

Mesoscale Discussions in Virginia, 2007 Every mesoscale discussion in 2007

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.