Alert archive / Pennsylvania / Mesoscale Discussions in 2013
Mesoscale Discussion 556
The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2013, 3:36 PM EDT for Carroll County, Frederick County, Washington County, Maryland; 30 counties in Pennsylvania; Berkeley County, Jefferson County, Morgan County, West Virginia. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Apr 24, 2013, 3:36 PM EDT (19:36 UTC)
- Expired
- Apr 24, 2013, 5:00 PM EDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 36 counties
Carroll County, MD, Frederick County, MD, Washington County, MD, Adams County, PA, Bedford County, PA, Blair County, PA, Bradford County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Lycoming County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA, York County, PA, Berkeley County, WV, Jefferson County, WV, Morgan County, WV
The radar
The State College radar (KCCX), 54 km from the middle of the area, began a volume at 19:39 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.
The nearest sounding before it
Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.6 hours before the alert went out and 175 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 615 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 224 m²/s²
- 0-3 km storm-relative helicity
- 231 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 |
|---|---|---|---|---|
| Apr 24, 6:59 PM EDT | Mesoscale Discussion | SPC | Anne Arundel, Baltimore, Carroll, Cecil, Charles, Frederick and 7 more | 2 hr |
| Apr 24, 4:55 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Berks, Carbon, Chester, Columbia, Cumberland and 23 more | 3 hr |
Nearby
Mesoscale Discussions in Pennsylvania, 2013Mesoscale Discussions in Maryland, 2013Mesoscale Discussions in West Virginia, 2013Every 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.