Alert archive / Maryland / Mesoscale Discussions in 2003

Mesoscale Discussion 827

May 7, 20034 states

The Storm Prediction Center issued this mesoscale discussion at May 7, 2003, 6:07 PM EDT for 4 states. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: May 7, 2003, 6:07 PM EDT (22:07 UTC)
Expired: May 7, 2003, 7:00 PM EDT
In force: 53 min
Issued by: the Storm Prediction Center

All 48 counties

New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Berks County, PA, Chester County, PA, Columbia County, PA, Dauphin County, PA, Lancaster County, PA, Lebanon County, PA, Northumberland County, PA, Schuylkill County, PA, York County, PA, Arlington County, VA, Caroline County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Manassas, VA, City of Manassas Park, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Greene County, VA, King George County, VA, Madison County, VA, Orange County, VA, Prince William County, VA, Spotsylvania County, VA, Stafford County, VA, Westmoreland County, VA

The radar

The Sterling radar (KLWX), 50 km from the middle of the area, began a volume at 22:07 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 nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.1 hours before the alert went out and 84 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: 11 J/kg
Mixed-layer CIN: -276 J/kg
Mixed-layer LCL: 815 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 8 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
May 7, 12:49 PM EDT	Mesoscale Discussion	SPC	Allegany, Baltimore, Carroll, Cecil, Frederick, Garrett and 5 more	116 min
May 7, 1:20 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 7 more	6 hr
May 7, 3:21 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Carroll, Charles, Frederick and 6 more	114 min
May 7, 3:40 AM EDT	Severe Thunderstorm Watch	SPC	Lee	5 hr
May 7, 5:26 AM EDT	Mesoscale Discussion	SPC	Lee	2 hr

Nearby

Mesoscale Discussions in Maryland, 2003 Mesoscale Discussions in Virginia, 2003 Mesoscale Discussions in Pennsylvania, 2003 Every mesoscale discussion in 2003

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.