Alert archive / Virginia / Mesoscale Discussions in 2013

Mesoscale Discussion 101

January 30, 2013Charles County, Prince George's County, Maryland; 12 counties in North Carolina; 48 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jan 30, 2013, 4:06 PM EST for Charles County, Prince George's County, Maryland; 12 counties in North Carolina; 48 counties in Virginia. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Jan 30, 2013, 4:06 PM EST (21:06 UTC)
Expired: Jan 30, 2013, 6:00 PM EST
In force: 114 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 62 counties

Charles County, MD, Prince George's County, MD, Alamance County, NC, Chatham County, NC, Davidson County, NC, Durham County, NC, Franklin County, NC, Granville County, NC, Guilford County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Vance County, NC, Warren County, NC, Albemarle County, VA, Amelia County, VA, Arlington County, VA, Augusta County, VA, Brunswick County, VA, Caroline County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Manassas, VA, City of Manassas Park, VA, City of Petersburg, VA, City of Richmond, VA, City of Staunton, VA, City of Waynesboro, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Henrico County, VA, King George County, VA, King William County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mecklenburg County, VA, Nelson County, VA, Nottoway County, VA, Orange County, VA, Page County, VA, Powhatan County, VA, Prince Edward County, VA, Prince William County, VA, Rappahannock County, VA, Rockingham County, VA, Spotsylvania County, VA, Stafford County, VA

The radar

The Roanoke radar (KFCX), 133 km from the middle of the area, began a volume at 21:07 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.

Tornado Watch 24Jan 30, 6:30 PM EST

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 9.1 hours before the alert went out and 65 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: 5 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 561 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 299 m²/s²
0-3 km storm-relative helicity: 488 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
Jan 30, 8:31 AM EST	Severe Thunderstorm Watch	SPC	Garrett	4 hr
Jan 30, 10:19 AM EST	Mesoscale Discussion	SPC	Allegany, Frederick, Garrett, Washington	86 min
Jan 30, 12:54 PM EST	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Baltimore, Carroll, Charles, Frederick and 6 more	96 min
Jan 30, 6:31 PM EST	Tornado Watch	SPC	Anne Arundel, Baltimore, Calvert, Carroll, Charles, Harford and 5 more	8 hr
Jan 30, 5:51 AM EST	Tornado Watch	SPC	Cherokee, Clay	7 hr
Jan 30, 7:38 AM EST	Mesoscale Discussion	SPC	Swain	97 min
Jan 30, 8:11 AM EST	Tornado Watch	SPC	Graham, Jackson, Macon, Swain	7 hr
Jan 30, 12:50 PM EST	Mesoscale Discussion	SPC	Alexander, Avery, Buncombe, Burke, Caldwell, Catawba and 21 more	85 min
Jan 30, 1:19 PM EST	Tornado Watch	SPC	Alexander, Avery, Buncombe, Burke, Cabarrus, Caldwell and 22 more	9 hr
Jan 30, 3:21 PM EST	Mesoscale Discussion	SPC	Alleghany, Rockingham, Stokes, Surry, Wilkes, Yadkin	84 min
Jan 30, 3:42 PM EST	Severe Thunderstorm Watch	SPC	Alleghany, Ashe, Caswell, Rockingham, Stokes, Surry and 3 more	5 hr
Jan 30, 4:13 PM EST	Mesoscale Discussion	SPC	Gaston, Mecklenburg	2 hr

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.